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THE 
 
 MICROSCOPE 
 
 Made Eafy : 
 
 O R, 
 
 I. The Nature, Ufes, and Magnifying Powers. 
 of the beft Kinds of Microscopes 
 
 Defcribed, Calculated, and Explained: 
 
 FOR THE 
 
 Inftruction of fuch, particularly, as defire to fearch 
 
 into the Wonde r s of the Minute Creation, 
 
 tho' they are not acquainted with Optics. 
 
 Together with 
 
 Full Directions how to prepare, apply, examine, and prefcrvt 
 
 all Sorts of Objects, and proper Cautions 
 
 to be obfcrved in viewing them. 
 
 II. An Account of what furprizing Difccveries 
 have been already made by the A'Iicroscope : 
 
 With uferul Reflections on them. 
 
 AND ALSO 
 
 A great Variety of new Experiments and Obfervations, 
 
 pointing out many uncommon Subjeds ior the 
 
 Examination of the Curious. 
 
 By HE NET BAKEP, Fellow of the Royal Society, 
 and Member of the Society of Antiquaries , in London. 
 
 Illuftrated with Copper Plates. 
 
 Return Natura nufquam magis quam in Minimis tota eft. 
 Plin. Hift. Nat. Lib. XI. c. 2. 
 
 LONDON: 
 
 Printed for R. Dodsley, at Tull/s Head in Pall-Mall. 
 
 • «- . . 
 
 M, DCC. XUJ, 
 
At a Meeting of the Royal Society \ 
 OElob. 28. 1742. 
 
 IMPRIMATUR. 
 
 M. Folkes, Pr. R. S. 
 
i • « 
 
 busty 
 
 C.2- 
 
 T O 
 
 /> 
 
 Martin Folkes, £/^; 
 
 PRESIDENT, 
 
 And to the 
 
 COUNCIL and FELLOWS 
 
 OF THE 
 
 Royal Society of London. 
 
 Gentlemen, 
 
 N Attempt to excite in 
 Mankind a general Defire 
 of fearching into the Won- 
 ders of Nature, will, I 
 pcrfuade myfelf, be accepted favour- 
 ably by You, whofe Endeavours for 
 the Advancement of Natural Know- 
 ledge, according to the Purpofe of 
 your Institution, are efteem'd by all 
 the World. 
 
 A It 
 
ii DEDICATION. 
 
 It is fomething more than an 
 hundred and twenty Years fince the 
 Microscope was happily invented; 
 and to the valuable Difcoveries made 
 thereby, we ftand indebted, as the 
 following Sheets will mew, for a 
 great part of our prefent Philofophy. 
 In fuch a length of Time, it is how- 
 ever probable, many more Advanta- 
 ges might have been reaped from it, 
 had not fome Difficulties and Difcou- 
 ragements prevented its general Ufe. 
 
 At the beginning it was confined 
 to very few ; who, making a Secret 
 of it, endeavoured all they could to 
 keep it to themfelves^ and, when it 
 became a little more publick, the 
 Price was fixt fo high, that the moft 
 Curious and Industrious, who have 
 not always the greater!: Share of 
 Money, could not conveniently get 
 at it. Of late Years, indeed, the 
 Expence has been much lefs ; but 
 then newDifcouragements have Start- 
 ed up from Miftake and Prejudice. 
 
 For 
 
DEDICATION. iii 
 
 For many have been frighted from 
 the Uie or it, by imagining it re- 
 quired great Skill in Optics, and 
 abundance of other Learning, to 
 comprehend it to any Purpofe : 
 whereas nothing is really needful but 
 good Glaffes, good Eyes, a little 
 Practice, and a common Underftand- 
 ing, to diftinguifli what is feen ; and 
 a Love of Truth, to give a faithful 
 Account thereof. Others have con- 
 fider'd it as a nicer Play- thing, a 
 matter of Amufement and Fancy 
 only, that raifes our Wonder for a 
 Moment, but is of no farther Ser- 
 vice : which Miftake they have fall- 
 en into from being unacquainted 
 with any Principles whereby to form 
 a right Judgment of what they fee. 
 Many, again, have laid the Micro- 
 fcope afide, after a little Ufe, for 
 want of knowing what Objects to 
 examine, where to find, how to 
 prepare, and in what manner to ap- 
 ply them. The Trouble of manag- 
 ing it has alfo frighted fome. 
 
iv DEDICATION. 
 
 But we are now fo fortunate to 
 have this Inftxument greatly improv- 
 ed amongft ourfelves, the Apparatus 
 made much eafier as well as more 
 ufeful, and the Price confiderably 
 reduced. The Solar or Camera Ob- 
 fcura Microfcope, and the Micro- 
 fcope for viewing Objects that have 
 no Transparency, by throwing a 
 ftrong reflected Light upon them, 
 are alfo new Inventions, from whence 
 great Things may be expecled. 
 
 Nothing therefore is now want- 
 ing, but a general Inclination to 
 employ thefe Inftruments, for a far- 
 ther Difcovery of the Minute Won- 
 ders of the Creation ; which may not, 
 perhaps, improve our Knowledge 
 lefs than the grander Parts thereof. 
 Bears, Tigers, Lions, Crocodiles and 
 Whales, Oaks and Cedars, Seas and 
 Mountains, Comets, Stars, Worlds 
 and Sims, are the Capitals in 
 Nature's mighty Volume, and of 
 them we fhould not be ignorant : 
 
 but 
 
DEDICATION. v 
 
 but whoever would read there with 
 Understanding, muft make himfelf 
 Mafter of the little Letters likewife, 
 which occur a thoufmd times more 
 frequently, and, if he does not know 
 them, will flop him fhort at every 
 Syllable. 
 
 The likeliefl: Method of difcover- 
 ing Truth, is, by the Experiments 
 of Many upon the fame Subject ; and 
 the moft probable Way of engaging 
 People in fuch Experiments, is, by 
 rendring them ealy, intelligible and 
 pleafant. To effect this is my En- 
 deavour in the following Treatife, 
 which may ferve as the Reprefenta- 
 tion of an Object for the Inftrument 
 I am recommending ; fmall, indeed, 
 and feemingly of no Confequence ; 
 but what, upon Examination, will 
 be found, perhaps, to contain as 
 many ufeful Parts as thofe that are 
 much bulkier : for, to drop the AI- 
 lufion here, I am certain, that with 
 half the Pains I could have made it 
 twice as large. A 3 
 
vi DEDICATION. 
 
 Think me not fo prefumptuous to 
 dream of inftrudling you in Matters 
 you are much better acquainted with 
 than I can pretend to be; but give 
 me leave to requeft the Favour of 
 your Concurrence, in my Defire of 
 explaining, to thofe that are igno- 
 rant, a Science that may prove of 
 the moft eminent Service towards the 
 Advancement of True Knowledge, 
 and in which every body that has 
 Inclination and Opportunity may be 
 able to do fomething. ' 
 
 Excufe my Miftakes, forgive my 
 detaining you thus long, and permit 
 me the Honour to be, with all pofli- 
 ble Refpect and Veneration, 
 
 Gentlemen, 
 
 Your moft Obedient 
 
 and devoted Humble Serv c , 
 
 Henry Baker. 
 
( vii ) 
 
 Contents of the Chapters, 
 
 PART the FIRST. 
 INTRODUCTION, p. xi. 
 
 CHap. I. Of Micro fcopes in general, p. i 
 Chap. II. Of the Kinds of Mi cr of copes, 7 
 
 Chap. III. Mr. Wi lson'j Single Pocket- 
 Microfcope, 9 
 
 Chap. IV. A new Invention for fxing the 
 Pocket- Microfcope, and giving Light to it 
 by a Speculum, 1 4 
 
 Chap. V. Of the Double Reflecting Micro- 
 fcope, 1 6 
 
 Chap. VI. The Solar or Camera Obfcura 
 Microfcope, 2 2 
 
 Chap. VII. The Microfcope for Opake Ob- 
 jects, 2 6 
 
 Chap. VIII. Toflnd the magnifying Power of 
 Glaffes employed in Single Microfcopes, 3 1 
 
 Chap. IX. The magnifying Power of Glaffes 
 
 in the Double Microfcope ', 3 9 
 
 A 4 Chap. 
 
viii Contents of the Chapters. 
 
 Chap. X. To find out the real Size of Objects 
 '■ view d. by Micro/copes, 40 
 
 Chap. XL The Area, or Portion of an Ob- 
 ject feen, 48 
 Chap. XII. Of Obj eels in general, 50 
 Chap. XIII. Of examining Objects, 52 
 Chap. XIV. Of preparing and applying Ob- 
 jects, 56 
 Chap. XV. Cautions in viewing Objects, 62 
 
 PART the SECOND. 
 
 ^Hap. I. Of the Animalcules in Fluids, 68 
 ^ Chap. II. To make Pepper-Water, 7 1 
 Chap. III. Of Hay-Water, 76 
 
 Chap. IV. Of Eels in Pajle, 81 
 
 Chap. V. Of Rain-Water and other Wa- 
 ters, 83 
 Chap. VI. An Examination of the Blood in 
 Animals, 102 
 Chap. VII. Some Account of the Blood, as 
 examined by the Microfcope, 103 
 Chap. VIII. Of viewing the Blood with the 
 Microfcope, 1 1 2 
 Chap, IX. The Circulation of the Blood, 1 \j 
 Chap. X. Of viewing the Current and Cir- 
 culation of the Blood, 120 
 Chap. XL The Pulfation of the Heart, 1 %y 
 Chap. XII. Of the mujcular orfefiy Fibres 
 of Animals 3 130 
 
 Chap, 
 
Contents of the Chapter?. ix 
 
 Chap. XIII. Of Bones, 143 
 
 Chap. XIV. OfYhe'Nerues; 145 
 
 Chap. XV. Of the Generation of Animate 
 and Vegetables, 148 
 
 Chap. XVI. Of the Animalcules in Scmine 
 Mafculino, 152 
 
 Chap. XVII. Animalcules in the Teeth, i6y 
 Chap. XVIII. Of the Itch, 169 
 
 Chap. XIX. Of Scales on the Human Skin, 172 
 Chap. XX. Of the Pores of the Shin, 174 
 Chap. XXI. Of the Lou/e, j 7? 
 
 Chap. XXII. Of the Wood-Loufe, 185 
 
 Chap. XXIII. Of Mites, 186 
 
 Chap. XXIV. Of the Flea, 1 9 1 
 
 Chap. XXV. Of Spiders, 196 
 
 Chap. XXVI. Of the Gnat, 203 
 
 Chap. XXVII. Of the Ox-Fly, or Gad- 
 Bee, 207 
 Chap. XXVIII. Of the Stings oflnfe&s, 20 > 
 Chap. XXIX. Of a Bees Sting, 2*10 
 Chap. XXX. Of the Sting of a Scorpion, 2 1 2 
 Chap. XXXI. OfthePovfon of a Viper, 215 
 Chap. XXXII. Of the Snail, 217 
 Chap. XXXIII. Of the common FU, 219 
 Chap. XXXIV. Of the Weevil, " or Corn- 
 Beetle, 221 
 Chap. XXXV. Of the Wolf, 223 
 Chap. XXXVI. Of the pearled Eyes of In- 
 fers, 226 
 Chap. XXXVII. Of the Antenna?, Feelers, 
 or Horns of Injects, 230 
 Chap. XXXVIII. Of the Wings of Infers, 
 
 2;2 
 
 ■•>■ 
 
x Contents of the Chapters. 
 
 Chap. XXXIX. Of the Balances or Poifes 
 bflnfeBs, . 235 
 
 Chap. XL . Of the Scales of Fifies, 236 
 
 Chap.XLI. OftheOyfter, 239 
 
 Chap. XLII. Of the Light on Oyfters, 241 
 Chap.XLIII. OftheMuJcle i 242 
 
 Chap.XLIV. Of Hairs, 245 
 
 Chap. XLV. Of the Farina of Flowers, 247 
 Chap.XLVI. Of Seeds, 251 
 
 Chap. XLVII. Of Leaves, 256 
 
 Chap. XL VIII. Of Salts in general, 259 
 Chap. XLIX. Of Salts in Mineral Waters, 
 
 262 
 
 Chap. L. Mifcellaneous D if cover ies and Ob- 
 
 fervations, 265 
 
 Chap. LI. The Works of Art and Nature 
 
 compared and confiderd, 292 
 
 Chap. LII. Some reafonable Refections on 
 
 Difcoveries made by the Micro/cope, 300 
 
 THE 
 
( * ) 
 
 THE 
 
 INTRODUCTION. 
 
 N tills inquifitive Age, when the 
 Defire of Knowledge has fpread 
 itfclf far and wide, and we fit 
 not down contented, as hereto- 
 fore, with the Opinions of ancient Times, 
 but refolve to examine for Ourfelves, and 
 judge from our own Experience ; it may 
 not, perhaps, prove unacceptable, to point 
 out fome proper Subjects of Enquiry. 
 
 The Works of Nature are the only Source 
 of true Knowledge, and the Study of them 
 the moft noble Employment of the Mind of 
 Man. Every Part of the Creation demands 
 his Attention, and proclaims the Power and 
 Wifdom of its Almighty Author. The 
 fmalleft Seed, the minuteil InfecT: mews the 
 
 Skill 
 
xii The INTRODUCTION. 
 
 Skill of Providence in the Aptnefs of its 
 Contrivance for the Purpofes it is to ferve, 
 and difplays an Elegance of Beauty beyond 
 the utmoft Stretch of Art. 
 
 The Wife in all Ages have been fenfible 
 of this Truth ; and, as far as they were able, 
 have ftudied and enquired into the RecelTes 
 of Nature ; but for want of proper Helps 
 have frequently been miftaken. As certain 
 Principles muft firfl be learn'd e'er we can 
 become Matters of any Science, fo in the 
 School of Nature, we mufl begin with the 
 Minutice, the fmallefr. and moil uncom- 
 pounded Parts, e'er we can underftand the 
 larger and more confiderable. 
 
 The Ancients, having only their naked 
 Eyes to trufr. to, were uncapable of any 
 great Difcoveries of this Sort : but we are fo 
 happy, that, by the Help of GlalTes, we can 
 diftinguiih and examine Objects many thou- 
 fands of times lefs than what the fharp- 
 eft Eye, unafiifted, can difcern. In fhort, 
 Microscopes furnifh us as it were with a 
 new Senle, unfold the amazing Operations 
 of Nature, and prefent us with Wonders un- 
 thought of by former Ages. 
 
 Who, a thoufand Years ago, would have 
 
 imagined it poffible,. to diftinguiih Myriads 
 
 2 of 
 
The INTRODUCTION. .\iii 
 of living Creatures in a fingle Drop of Wa- 
 ter ? Or that the purple Tide of Life, and 
 even the Globules of the Blood fhould be 
 ken diftinclly, rolling thro' Veins and Arteries 
 fmaller than the fined; Hair ? That Millions 
 of Millions of Animalcules fhould be difco- 
 vered in the Semen Mafculimtm of all Crea- 
 tures ? That not only the exterior Form, 
 but even the internal Structure of the Bowels, 
 and the Motion of the Fluids in a Gnat or 
 Loufe, (hould be render'd Objects of Sight ? 
 Or that numberlefs Species of Creatures 
 fhould be made viiible, tho' fo minute that 
 a Million of them are lefs than a Grain of 
 Sand ? 
 
 Thefe are noble Dz'fcovcries, whereon a 
 new Philofophy has been raifed, that enlar- 
 ges the Capacity of the human Soul, and 
 furnifhes a more jufl and iublime Idea than 
 Mankind had before, of the Grandeur and 
 Magnificence of Nature, and the infinite 
 Power, Wifdom, and Goodnefs of Nature's 
 Almighty Parent. 
 
 That Man is certainly the happiefr., who 
 is able to find out the greateft Number of 
 reafonable and ufeful Amufements, eafily 
 attainable and within his Power : and, if fo, 
 he that is delighted with the Works of Na- 
 ture, and makes them his Study, mull: un- 
 doubtedly 
 
xiv The INTRODUCTION. 
 doubtedly be happy ; fince every Animal, 
 Flower, Fruit, or Infect, nay, almoft every 
 Particle of Matter, affords him an Enter- 
 tainment. Such a Man never can feel his 
 Time hang heavy on his Hands, or be weary 
 of himfelf, for want of knowing how to em- 
 ploy his Thoughts : each Garden or Field is 
 to him a Cabinet of Curiofities, every one 
 of which he longs to examine fully j and 
 he confiders the whole Univerfe as a Maga- 
 zine of Wonders, which infinite Ages are 
 fcarce fufTicient to contemplate and admire 
 enough. 
 
 The Invention of GlafTes has brought 
 under our Examination the two Extreams of 
 the Creation, if I may be allowed to call 
 them fo, which were out of the Reach of 
 former Ages : I mean, thofe van: and diftant 
 Bodies of our Syftem, the Sun and Planets ; 
 whofe Dimenfions, Diftances, Motions, Re- 
 gularity, and Order we are become acquaint- 
 ed with by the Help of Telescopes, and 
 thofe exceedingly minute, and to them in- 
 vifible, and unknown (tho* every where at 
 hand) Species of Animals, Plants, Gfc. which 
 the Microscope has difcover'd to us. I 
 leave the Telescope to others, who are 
 better able to do it JuiKce : my Intent in 
 this Difcourfe is to treat of the M i c r o- 
 scope, and encourage its more general Ufe, 
 2 by 
 
Tie INTRODUCTION. xv 
 
 by mewing the Pleafure and Inftru&ion it 
 can afford us. 
 
 Mr. Boyle fays, in his Difcourfe of the 
 Ufejuhiefs of Experime?ital Philofopby J that 
 his Wonder dwells not fo much on Nature's 
 Clocks as on her Watches ; and, indeed, up- 
 on comparing the Structure of a Mite with 
 that of an Elephant ; , I believe we mall con- 
 cur in the fame Opinion. The Largenefs 
 and Strength of the One may ftrike us with 
 Wonder and Terror, but we iliall find our- 
 felves quite loft in Amazement, if we atten- 
 tively examine the feveral minute Parts of 
 the Other. For the Mite has more Limbs 
 than the Elephant, each of which is furnim- 
 ed with Veins and Arteries, Nerves, Mufcles, 
 Tendons and Bones : it has Eyes, a Mouth, 
 and a Probofcis too (as well as the Elephant) 
 to take in its Food ; it has a Stomach to 
 digeft it, and Inteftines to carry off what is 
 not retained for Nourishment : it has an 
 Heart to propel the Circulation of its Blood, 
 a Brain to fupply Nerves every where, and 
 Parts of Generation as perfect as the largeft 
 Animal. Let us now Hop, look back, and 
 confider, as far as our Abilities can reach, 
 the exceffive Minutenefs of all thefe Parts ; 
 and if we find thorn fo furprizing and be- 
 yond our Ideas, what mall we fay of thofe 
 
 many 
 
xvi <tbe INTRODUCTION. 
 
 many Species of Animalcules^ to whom a 
 Mite itielf, in Size, is as it were an Ele- 
 phant ? 
 
 All thefe, and numberlefs Wonders more, 
 the Microscope can exhibit to us. I {hall 
 therefore proceed to defcribe this noble In- 
 vention, mew how far it is improved at pre- 
 fent, give a brief Account of what Difcove- 
 ries have been made, and point out fome 
 Objects for the Curious to examine by it. 
 In doing this I mall avoid as much as porli- 
 ble all Affectation of Learning, or Expref- 
 fions that are not in common Speech, being 
 derlrous that every body may understand me. 
 
 THE 
 
( t ) 
 
 > < P W\^^> -72 
 
 gym 
 
 - 
 
 THE 
 
 MICROSCOPE 
 
 Made Eafy, &fc. 
 
 CHAP. I. 
 
 Of Microscopes in General. 
 
 Y Microscopes we are under- 
 itood to mean, lnjiruments of 
 whatever Stru&ure or Contri- 
 vance, that can make jmall Ob- 
 
 jecls appear larger than they do to the naked 
 
 Eye. 
 
 This is effected by Glaffes formed con- 
 vex. 
 
 B When 
 
2 (^Microscopes in general. 
 
 When only one fuch convex Glafs or 
 * Lens is ufed for this intent, the Inftrument 
 it is fixt in, however famioned, is called a 
 Single Micro/cope : but if two or more Glaf- 
 ies are employed, conjoyntly, to magnify 
 Objects more, it is then called a Double or 
 Compound Micro/cope. 
 
 One remarkable Difference in the Effect 
 of thefe two Inftruments is, that an Object 
 view'd through a iingle convex Glafs, appears 
 magnified, in the fame Pofition exactly as 
 when {ten by the naked Eye; but when 
 view'd through a Double Microfcope, com- 
 pofed of three convex Glaffes, all Parts of it 
 become inverted : that is, the Top of the 
 Object appears at Bottom, the Right-fide on 
 the Left, and every Part in the Place mod 
 oppofite to its natural and true Pofition : 
 The Lights and Shades being alfo inverted, 
 the finking parts appear to rife, and the riling 
 parts to fink in. 
 
 To what Accident, to what Country, or 
 to whom we are obliged for the Invention 
 
 * The Word Lens properly fignifies a fmal! Glafs in figure 
 ©f a Lentil ; but is extended to any Optic Glafa nut very 
 thick, which either colie&s the Rays of Light into a Point 
 in their Tallage thro' it, or difperfes them apart, according 
 to the Laws of Re fra cl ion. If convex on both Sides, it is 
 cdUd a Convex Lens ; but if one Side be flat, a Plano- 
 Convex : If concave en both Sides, it is term'd a Concave 
 L . j if flat on one Side, a Plano-Concmje ; if convex on 
 oae Side and conc&ve on the other, a Convexs -Concave, or 
 Concavo' L onvex. 
 
 1 of 
 
0/ M I c R o s c o P e s in general. 3 
 
 of Microfcopes, i; not in me to determine : 
 the Honour has been given by fome to 
 Dkeebel a Dutchman, by others to Fox- 
 tana a Neapolitan, su .: I y others Aill to 
 different People. The firft Appearance of 
 them however was about the Year 162 1 5 
 fince when they have been improving down 
 to the prefent i'ime. 
 
 As my Defile is to make People fenfible 
 of the Pleafnre and Information the Micro- 
 icope can afford, and inflruct them how to 
 manage and undcrftand it, rather than how 
 ; • m: ke it, I (hall take up none of their 
 
 ne with the Manner of melting, griud- 
 ing, polishing, or letting of glafles 5 a Work 
 very few of mv Readers will ever trouble 
 themfelves about. But, infread thereof, Khali 
 endeavour, with all the Brevity and Clear- 
 I am able, to explain the Effects of 
 Glaffes on the Sightj and lead them gradu- 
 ally into the Nature, \Jfc$ y and magnifying 
 Powers of Microfcopes. 
 
 When Obje£tS are feen through a per- 
 fectly fiat Glafs, the Rays of Light pafs 
 through it from them to the Eye in a (trait 
 Direction, and parallel to each other j and, 
 confequentlv, the Objects appear very little 
 either niminifhed, or enlarged, or nearer, or 
 farther off, than to the naked Eye. But if 
 the Glafs they are feen through has any De- 
 gree of Convexity, the Rays of Light are 
 directed from the Circumference towards 
 
 B 2 the 
 
4 Of Microscopes in general. 
 the Center, in an Angle proportionable to 
 the Convexity of the Glafs, and meet in a 
 Point, at a greater or lefs Diftance from the 
 Glafs, as it is lefs or more convex. This 
 Point, where the Rays meet, is called the 
 Focus j and this Focus is nearer or farther 
 off, according to the Convexity of the Glafs: 
 for as a little Convexity throws it to a con- 
 iiderable Diftance, when the Convexity is 
 much, the Focus is very near. Its magni- 
 fying Power is alfo in the fame Proportion 
 to the Convexity : for as a flat Glafs magni- 
 fies fcarce at all, the lefs a Glafs departs 
 from Flatnefs, the lefs of courfe it magni- 
 fies ; and the more it approaches towards a 
 globular Figure, the nearer its Focus is, and 
 the more its magnifying Power. 
 
 People's different Length of Sight depends 
 on the fame Principle, and arifes from a 
 more or lefs Convexity of the Cornea and 
 Cryjialline Humour of the Eye : the round- 
 er thefe are, the nearer will the Focus or 
 Point of meeting Rays be, and the nearer 
 an Object muft be brought to fee it well. 
 The Cafe of fhort-fighted People is only an 
 over Roundnefs of the Eye, which makes a 
 very near Focus ; and that of old People is 
 a finking or flattening of the Eye, whereby 
 the Focus is thrown to a great Diftance : 
 ib that the former may properly be called 
 Eyes of too fliort, and the latter Eyes of too 
 long a Focus. Hence too, the Remedy for 
 
 the 
 
Of M i c p o s c o p e s * « general. 5 
 the lair, is a convex Glafs, to fupply the 
 want of Convexity in the Eye itfelf, and 
 bring the Rays to a fhorter Focus ; whereas 
 a concave Glafs is needful for the firit, to 
 fcatter the Rays, and prevent their coming 
 to a Point too foon. 
 
 Nothing is more common than to obferve 
 old People holding Objects they would ex- 
 amine at a great Diftance from them, for 
 the Reafon above-mentioned ; and every 
 body knows, fhort- lighted People cannot 
 diftinguifli any thing without bringing it 
 very near their Eyes. Both Extremes are 
 inconvenient j but thofe whofe Eyes are flat 
 by Age, mould remember with Satisfaction, 
 that they have enjoy'd the Pleafure of them 
 for many Years ; and the fhort-iightcd may 
 comfort themfclves, that they can difTin- 
 gui(h much fmallcr Objects than long right- 
 ed People; for the Object is magnify 'd in 
 Proportion to the Roundnefs of the Eye and 
 the Nearnefs of the Focus, and confequent- 
 ly appears four times as big to an Eye whofe 
 Focus is but four Inches off, as it does to 
 one whofe focal Diftance is at eight Inches. 
 They have alfo this farther Advantage, that 
 Age improves their Eyes, by the fame means 
 it impairs other People's, that is, by mak- 
 ing them more flat. 
 
 The nearer any Object can be brought to 
 
 the Eye, the larger will be the Angle under 
 
 which it appears, and the more it will be 
 
 B 3 mag- 
 
6 Of Microscopes in general. 
 magnified. Now, that Diftance from the 
 naked Eye, where the generality of People 
 are fuppoied to fee fmall Objects bed:, is, at 
 about eight Inches ; consequently, when fuch 
 Objects are brought neater than eight Inches, 
 (fuppofe to fix) they'll become iefs diftinct \ 
 and if nearer ftili, on to four or three, they 
 will fcarce be feen at all. But by the help 
 of convex Glaffes we are enabled to view 
 things clearly at much fhorter Diftances 
 than thefe : for the Nature of a convex Lens 
 is, to render an Object diftinctly vifrble to 
 the Eye at the Diftance of its Focus; 
 wherefore the fmaller a Lens is, and the 
 more its Convexity, the nearer is its Focus, 
 and the more its magnifying Power. 
 
 As it is an eafy matter to melt a Glafs 
 Drop or Globule of a much fmaller Dia- 
 meter than any Lens can poiTibly be ground, 
 and as the Focus of a Globule is no farther 
 off than one quarter of its own Diameter, 
 and confequently it mud: magnify to a pro- 
 digious Degree, fome Years ago People were 
 extremely fond of fuch Globules, and ima- 
 gin'd no good Microfcope could be without 
 them : but Experience has iince taught, that 
 they admit fo little Light, can fliew fuch an 
 exceedingly minute part only of any Ob- 
 ject, are fo difficult to make ufe of, and 
 itram the Eyes fo much, that their Power of 
 magnifying, for want of due Diftinctnefs, 
 is rather apt to produce Error than discover 
 
 Truth ; 
 
Of the Kinds of Microscopes. 7 
 Truth : and therefore now they are very 
 rarely employed. 
 
 C II A P. II. 
 
 Of the Ki?ids of Microscopes. 
 
 MIcroscopf.s are either Single or 
 Double : the Single have but one 
 Lens ; the Double are a Combination of 
 two or more. Each of thefe two Kinds has 
 its particular Advantage : for a iingle Glafs 
 mews the Object nearer at hand, and rather 
 more diltinct ; and a Combination of Glaf- 
 fes prefents a larger Fluid, or, in other 
 Words, exhibits more of an Object, equally 
 magnified, at one View. It fa difficult to 
 determine which of thefe to recommend, 
 frncc each affords a different Kind of Pica* 
 fare. Each of them too can produce con- 
 fiderable Authorities m its Favour ; for Mr. 
 L e e u w enhcek never ufed any but * fingle 
 
 * Several Writers reprefent the Glailes Mr.L.E eu wen ho ek 
 
 rm-de ufe of in his Microfcopcs to be little Globules or 
 
 Spheres of Glafs, which Miftake moll probably arifes from 
 
 weir undertaking to defcribe what they had never feen : 
 
 at iheTime f am writing this, the Cabinet of Micro- 
 
 iVopcs left by that famous rvhn, at his Death, to the Royal 
 
 .», as a Legacy, is Handing upon my Table ; and I can 
 
 ■ the World, that every one of the twenty-fix Micro- 
 
 1 d therein is a double convexXens, and not a 
 
 re 01 Globule. 
 
 B 4 Micro- 
 
8 Of the Kinds of Microscopes. 
 Microfcopes j and, on the contrary, Mr. 
 Hooke made all his Obfervations with 
 double ones. 
 
 The famous Microfcopes of Mr. Leeu- 
 wenhoek are the moft fi tuple pofiible, be- 
 ing only a fingle Lens, fet between two Plates 
 of Silver perforated with a fmall Hole, with a 
 moveable Pin before it to place the Object 
 on, and adjufl: it to the Eye of the Beholder. 
 By thefe he made thofe wonderful Difcove- 
 ries which furprized the World fo much, 
 and introduced a new Syftem of Philofophy 
 andReafoning, as in theCourfe of thisTrea- 
 tife I fhall find occafion more at large to 
 mention. 
 
 There are many pretty little Contrivances 
 fold at the Shops for the viewing of fmall 
 Objects, which are entertaining as far as can 
 reafonably be expected from them : but to 
 enumerate all thefe would be a tedious Tafk. 
 It would alfo be a matter more of Curiofity 
 than Profit, to defcribe the Forms and Ap- 
 paratus of the feveral Kinds of Microfcopes 
 that have been contrived fince the firft In- 
 vention of them. I mail therefore confine 
 my felf to give an account of fuch only in 
 ufe among ourfelves at prefenr, as by having 
 a proper Set of GlafTes, gradually magnifying 
 one above another, are fit to make Diicove- 
 ries of Confequence. 
 
 CHAP. 
 
( 9 ) 
 
 CHAP. III. 
 
 Of Mr, Wilson'j Single Pocket - 
 Micro/cope. 
 
 r l n HE fir ft: that I fliall mention, L>, 
 Mr. Wilson's Jingle Pocket Micro- 
 fcope; the Body whereof made either of 
 Brafs, Ivory, or Silver, is reprefented (Plate I.) 
 by A A. BB. 
 
 CC. is a long fine-threaded male Screw, 
 that turns into the Body of the Microfcope. 
 
 D. a convex Glafs at the End of the faid 
 Screw. 
 
 * Two concave round Pieces of thin Brafs, 
 with Holes of different Diameters in the 
 middle of them, to cover the faid Glafs, and 
 thereby diminifh the Aperture when the 
 grentefl Magnifiers are employed. 
 
 EE. three thin Plates of Brafs within the 
 Body of the Microfcope, one whereof is bent 
 icmicircularly in the middle, fo as to form 
 an arched Cavity for the Reception of a Tube 
 of Glafs, whereas the two flat Plates are to 
 receive and hold the Sliders between them. 
 
 F. a piece of Wood or Ivory, arched in 
 the Manner of the femicircular Plate, and 
 cemented thereto, 
 
 G. the other End of the Body of the- 
 Microfcope, where a hollow female Screw 
 is adapted to receive the different Magnifiers. 
 
 l H. 
 
io W i l s o n ' j jingle "Pocket Micro/cope. 
 
 H. a fpiral Spring of Steel, between the 
 faid End G and the Plates of Brafs ; intended 
 to keep the Plates in a right Polition, and 
 counteract againfl the long Screw CC. 
 
 I. a fmall turn'd Handle, for the better 
 holding of the Inilrument, to fcrew on or 
 off at pleafure. 
 
 To this Microfcope belong ftven different 
 magnifying GlaiTes : fix of them are fet in 
 Silver, Brafs, or Ivory, as in the Figure K, 
 and marked 1.2. 3. 4. 5. 6. the [owe ft 
 Numbers being the greateit Magnifiers. 
 
 L. is the feventh Magnifier, let in the 
 Manner of a little Barrel, to be held in the 
 Hand for the viewing any larger Object. 
 
 M. is a flat Slip of Ivory, called a Slider, 
 with four round Holes through it, where- 
 in to place Objects between two Glaffes or 
 Pieces of Mujcovy Talc, as they appear 
 d d d d. 
 
 Eight fuch Ivory Sliders, and one of Brafs, 
 are ufually fold with this Microfcope ; fome 
 with Objects placed in them, and others 
 empty, for viewing any thing that may of- 
 fer : but whoever pleafes to make a large 
 Collection of Objects, may have as many as 
 he defires, 
 
 The Brafs Slider is to confine any fmall 
 Object, that it may be viewed without 
 cradling; >r deftroving it. 
 
 N. is a Forceps, or Pair of Plyers, for the 
 taking up of Infects or other Objects, and 
 adjufting them to the GlafTes. 
 
\V 1 1. s o n 's jingle Pocuct Microfcope. 1 1 
 
 O. a little Hair-Brufh or Pencil, where-' 
 with to wipe any Dull from off the Glades, 
 or to take up any fmall Drop of Liquid one 
 Would examine, and put it Upon the Talcs 
 or Ifinglafs. 
 
 P. is a Tube of Gl.ifs, contrived to confine 
 living Objects, fuch as Frogs, Fifties, £ 
 in order to difcover the Blood, as it lire 
 a] >ng the Veins and Arteries. 
 
 All thefe Particulars are contained in a 
 little neat Box, very convenient for carrying 
 in tlie Pocket. 
 
 When an Object is to be view'd, thru ft 
 the Ivory Slider, in which the faid Object is 
 placed, between the two flat Brafs Plates 
 : obferving always to put that fide of the 
 Slider where the Brafs Rings are, fartheir 
 from your Eye. Then fcrew on the mag- 
 nifying Glafs you intend to ufe, at the End 
 of the Inflxumcnt G ; and looking through 
 it againft the Light, turn the long Screw 
 CC, till your Object be brought to fit your 
 Eye; which you will know by its appearing 
 
 then perfectly diltindt and clear. 'Tis bell 
 
 to look at it firft through a Magnifies thai 
 cm Ihew the Whole thereof at once, and 
 afterward^ to iufpeel: the feveral Parts more 
 particularly with one of the greatcil 
 firs : for thus you will gain a true Idea of 
 the Whole, and of all its Parts. And I 
 the greatcfr Magnifiers can {hew but a mi- 
 nute Portion of any Object at or.ee, iuch as 
 
 trie 
 
12 W I l s o n 's Jingle Pocket Microjcope: 
 the Claw of a Flea, the Horn of a Loufe, 
 or the like j yet by gently moving the Slider 
 that contains your Object, the Eye will gra- 
 dually overlook it all : and if any Part fhould 
 be out of Diftance, the Screw CC will eafily 
 bring it to the true Focus. 
 
 As Objects mufr be brought very near the 
 GlafTes when the greateit Magnifiers are 
 ufed, be particularly careful not to fcratch 
 them, by rubbing the Slider againft them, 
 as you move it in or out. A few Turns of 
 the Screw CC will eafily prevent this Mif- 
 chief, by giving them Room enough. 
 
 You may change the Objects in your 
 Sliders, for what others you think proper, 
 by taking out the Brafs Rings with the Point 
 of a Pen-knife ; the Ifinplafs will then fall 
 out, if you but turn the Sliders ; and after 
 putting what you pleafe between them, by 
 replacing the Brafs Rings, you will fatten 
 them as they were before. 'Tis proper to 
 have fome Sliders furnifhed with Talcs, but 
 without any Objects between them, to be 
 always in Readinefs for the Examination of 
 Fluids, Salts, Sands, Powders, the Farina 
 of Flowers, or any other cafual Objects of 
 fuch fort as need only be apply'd to the Out- 
 fide of the Talc. 
 
 The Circulation of the Blood may eafieft 
 be feen in the Tails or Fins of Fifties, in the 
 fine Membrane between a Frog's Toes, or, 
 beft of all, in the Tail of a Water-Newt. 
 
 If 
 
' Wilson's flngle Pocket Micro/cope. 13 
 
 If your Object be a fmall Fifh, place it with- 
 in the Tube, and ipread its Tail or Fin a- 
 gainit the Side thereof: if a Frog, chufe 
 fuch an one as can but jufl be got into your 
 Tube, and with a Pen or Stick expand the 
 tranfparent Membrane between the Toes of 
 the Frog's hind Foot as wide as you are able. 
 When your Object is fo adjured, that no 
 part thereof can intercept the Light from 
 the Place you intend to view, unicrcw the 
 long Screw CC, and thruft your Tube into 
 the arched Cavity, quite thro' the Body of 
 the Microfcope ; then (crew it to the true 
 focal Diftance, and you'll fee the Blood pall- 
 ing along its VelTels with a rapid Motion, 
 and in a moft furprizing Manner. 
 
 Make ufe of the third or fourth Magnifier 
 for Frogs, or Fifties ; but for the Tails of 
 Water-Newts, the fifth or fixth will do ; 
 becaufe the Globules of their Blood are twice 
 as large as thofe of Frogs or Fifh. The firft 
 or fecond Magnifier cannot well be employ- 
 ed to this Purpofe, for the Thicknefs of the 
 Tube wherein the Object lies, will fcarce 
 admit its being brought fo near as the focal 
 Distance of the Magnifier. 
 
 The Single Microfcope above defcribed, 
 may be formed into a Double One, by fere vy- 
 ing it to a Tube with an Eye-Glafs at the 
 End thereof: it is alio made to anfwer 
 nearly the Purpofes of the large Double Re- 
 flecting Microjcope by the Contrivance fol- 
 lowing. CHAP. 
 
1 4 Of the Pocket Microfcope 
 
 CHAP. IV. 
 
 A new Invention for fixing the Pocket Mi- 
 crofcope, and giving Light to it by a 
 Speculum. Plate 11. 
 
 IN this Plate, A is a Scroll of Brafs, nx'd 
 upright on a round Pedeflal of Wood, 
 B. fo as to (land perfectly tirrh and (leady, 
 
 C. is a Brafs Screw, that panes through a 
 Hole in the upper Limb of the Scroll, into 
 the Side of the Microfcope D, and fcrcws 
 it fa ft to the faid Scroll. 
 
 E. a concave Looking-glafs or Speculum, 
 fet in a Box of Brafs, which hangs in the 
 Arch G, by two fmall Screws ff that fcrew 
 into the eppofite Sides thereof. 
 
 At the Bottom of the faid Arch is a Pin 
 of the fame Metal, exactly fitted to a Hole 
 h, in the wooden Pedeflal, made for the 
 Reception of the faid Pin. 
 
 As the Arch turns on this Pin, and the 
 Speculum turns on the Ends of the Arch, it 
 may, by this twofold Motion, be eahly ad- 
 jufted, in fuch a Manner, as to reflect the 
 Light of the Sky, the Sun, or a Candle, 
 directly upwards, through the Microfcope 
 that is fixed perpendicularly over i ! : ; and 
 by fo doing, may be made to anfwer almoil 
 all the Ends of the large Double Reflecting 
 MitroJcope> which I {hall prefemly delcribe. 
 
 The 
 
fUZ. 
 
 r ' Ilijht'Jcu/p 
 
<with a Speculum. 15 
 
 The Body of the Microfcope may alfo be 
 fixt horizontally, and Objects may be view'd 
 in that Pofition, by any Light you chufe ; 
 which is an Advantage the Reflecting Micro- 
 fcope has not. 
 
 It may alio be rendered farther ufeful, 
 by means of a Slip of Glafs, one End of 
 which being thruil between the Plates where 
 the Sliders go, and the other extending to 
 fome Distance, fuch Objects may be placed 
 thereon, as cannot be applied in the Sliders : 
 and then, having a Limb of Brafs that may 
 fallen to the Body of the Microfcope, and 
 extend over the projecting Glafs a hollow 
 Rinc?; wherein to fcrew the Magnifiers, nil 
 forts of Subjects maybe examined with great 
 Conveniency, if a Hole be made in the Pe- 
 deftal, to place the Speculum exactly under- 
 neath, to throw up the Rays of Light. 
 
 The Pocket Microfcope thus fixt, is, if I 
 may prcfume to judge, as eafy and pleafant 
 in its L^fe, and as fit for the moft curious 
 Examination of the Animalcules and Salts in 
 Fluids, of the Farina. 1 in Vegetables, of the 
 Circulations in fmall Creatures : in fhort, it 
 is as likely to make confiderabie Difcovcries 
 in Objects that have fome Degree of Tranf- 
 parency, as any Microfcope I have ever feen 
 or heard of. It is alfo a material Part of the 
 Sola?' or Camera Obfcura Microfcope , which 
 I ilia 11 by and by defer ibe. 
 
 C II A P. 
 
1 6 The Double Reflecting Microfcope, 
 
 CHAP. V. 
 
 Of the Double Reflecting Microscope. 
 
 TH E Double Reflecting Microfcope in 
 ufe at prefent, (whofe Picture with 
 its Apparatus is feen Plate III.) is an Altera- 
 tion and Improvement by Mr. Culpeper 
 and Mr. Scarlet, of Mr. Marshall's 
 large Double Microfcope -, than which . it is 
 lefs cumberfome, may be managed with 
 much more Eafe, and by means of a re- 
 flected Light, is capable of fhewing Objects 
 in a clearer and more pleafing Manner. 
 
 The Body of this Microfcope A A A A, 
 being a large Tube, is fupported by three 
 Brais Pillars bbb, riling from a wooden Pe- 
 deftal C; in which Pedeftal is a Drawer D, 
 to hold the Object-Glanes and other Parts 
 of the Apparatus. 
 
 A leffer Tube e e, Aides into the greater, 
 and fends from its Bottom another Tube 
 much fmaller than itfelf, f with a male 
 Screw g y at the End thereof, whereon to 
 fcrew the Object-Glafs or Magnifier. 
 
 There are rive of thefe Magnifiers, num- 
 ber'd i, 2, 3, 4, 5, which Numbers are alfo 
 marked on the inner Tube, to direct where- 
 about to place it according to the Magnifier 
 made ufe of : but if then it fits not the Eye 
 exactly, Hide the inner Tube gently higher 
 
 or 
 
Paa. //> 
 
 /V., A ■///. 
 
The Double RefleSting Micro /cope, ij 
 
 or lower, or turn the Screw of the Magni- 
 fier gradually, till the Object appears dif- 
 tinct. Take notice, that the greateit Mag- 
 nifiers have the fmalleft Apertures and the 
 lowed Numbers. 
 
 L. is a circular Plate of Brafs, fixt hori- 
 zontally between the three Brafs Pillars, and 
 in the Center thereof a round Hole M. is 
 adapted to receive a proper Contrivance N. 
 for holding Ivory Sliders wherein Objects 
 are placed : which Contrivance confifts of 
 a fpiral Steel Wire confined between three 
 Brafs Circles, one whereof is moveable for 
 the Admiffion of a Slider. 
 
 O. is a round Brafs Plate, with feveral 
 Holes for placing Objects in, fome of which 
 are ufually furnilh'd with them at the Shops: 
 but two Holes are commonly referved for 
 fmall concave GlafTes, whereon to place a 
 Drop of any Liquid, in order to view the 
 Animalcules, &c. There is alfo a piece of 
 white Ivory, and a piece of black Ebony, 
 of the fame Size and Shape as the Holes for 
 Objects : the Ivory is to put opake Objects 
 on that are black, and the Ebony is to re- 
 ceive fuch as are white j by which Contra- 
 riety of Colours they will be fecn more 
 clearly.— At the Bottom of this Object- Plate 
 is a Button, to flip into a Slit P. that fits it, 
 on the circular Plate of Brafs : and by turn- 
 ing it round on this Pin, all the Objects 
 C may 
 
1 8 The Double RefcBing Micro/cope. 
 may be examin'd fucceflively with very little 
 Trouble. 
 
 Q^_is a concave Looking-glafs, fet in a 
 Box of Brafs, and turning in an Arch R. 
 upon two fmall Screws s s. From the Bot- 
 tom of the Arch comes a Pin, which by 
 letting down into a Hole /. in the Center of 
 the Pedeftal, enables it to turn vertically, or 
 horizontally, and reflect the Light, either of 
 a Candle, or the Sky, directly upwards on 
 the Object to be viewed. 
 
 V.- is a Plano-convex Lens, which by 
 turning on two Screws **, when the Pin at 
 the Bottom of it is placed in the Hole W. 
 for its Reception in the circular Plate L. will 
 tranfmit the Light of a Candle, to illuminate 
 any opake Object that is put on the round 
 Piece of Ivory, or on the Ebony, for Exami- 
 nation : and it may be moved higher or low- 
 er as the Light requires. This Glafs is of 
 good fervice to point the Sunmine, or the 
 Light of a Candle upon any opake Object; 
 but in plain Day-light it is of no great ufe. 
 
 X. a Cone of black Ivory, to fatten on a 
 Shank underneath the Brafs circular Plate L. 
 principally, when the firft or fecond Magni- 
 fier is made ufe of, and the Object very 
 tranfparent : for Experience teaches, that 
 fuch Objects are render'd much more dif- 
 tinctly vifible, by intercepting fome part of 
 the oblique Rays reflected from the concave 
 Looking-glafs. 
 
 The 
 
The Double Reflecting Micro/cope. i 9 
 The Brafs Fifh-pan Y. is, to faften a Smelt, 
 GudgCbfl, or any fuch fmall Filh upon, i ■ 
 fee the Blood circulate in its Tail. 1 
 which purpofe, the Tail of the Fiih rnuft 
 be fpread acrofs the oblong Hole at the 
 fmalleft End of the Pan : then, by flipping 
 the Button on the Eaeklide of the Pan into 
 the Slit P. through the circular Plate L. the 
 Spring that comes from the Button will make 
 it fteadv, and pfefeflt it well to View. • 
 
 But if it be a Frog, a Newt, or Eel, in 
 which the Circulation is defired to be (hewn, 
 a Glafs-Tube 1. is fitted for the purpofe. 
 The Tail of a Newt, or Eel, or, in a Frog, 
 the Web between the Toes of the Hind- 
 Feet, are the Parts where it may be feen 
 belt. When the Object is well expanded on 
 the Infide of the Tube, Hide theTube along 
 under the circular Brafs Plate L. (where there 
 are two Springs and a Cavity made in the 
 Shank to hold it) and bring your Object di- 
 rectly under the Magnifier. 
 
 There are three of thefc Glafs Tubes, 
 fmaller one than another, and the Size of 
 the Object: rnuft direct; which to life ; but in 
 general, the lefs Room the Creature has' to 
 move about in, the eafier it may be manag- 
 ed, and the quieter it will lye to be exa- 
 mined. 
 
 The Cell 2. with a concave and a plain 
 
 Glafs in it, is intended to confine Fleas, 
 
 Lice, Mites, or any fmall living Objects, 
 
 C 2 dklrin^ 
 
20 'The Double Reflecting Microfcope. 
 during pleafure ; and by placing it over the 
 Hole M. in the middle of the circular Brafs 
 Plate, they may be viewed with much Con- 
 
 veniency. Three loofe GlafTes, viz. one 
 
 plain, and two concave, belong alfo to this 
 Microfcope, and are deflgned to confine 
 Objects, or place them upon occafionally. 
 
 The long Steel Wire 3. with a pair of 
 Plyers at one End, and a Point at the other, 
 to hold fail, or flick Objects on, flips back- 
 wards or forwards in a Brafs fhort Tube, 
 whereto a Button is fattened, which fits in- 
 to the little Hole z y near the Edge of the 
 Brafs Plate L : and, then, the Object may be 
 readily brought to a right Pofition, and a 
 Light be caff upon it, either by the Looking- 
 glafs underneath, or, if it be opake, by the 
 Plano-convex Lens V. 
 
 4. is a flat Piece of Ivory called a Slider, 
 with four round Holes through it, and Ob- 
 jects placed in them, between Mufcovy Talcs 
 or Ifinglafs, kept in by Brafs Wires. 
 
 It is proper to have a Number of thefe 
 Sliders filled with curious Objects, always 
 ready, as well as fome empty ones, for any 
 new thing that offers. When made ufe of, 
 thruft them between the Brafs Rings of the 
 Contrivance on purpofe for them, N. which 
 moots into the round Hole M. in the Center 
 of the Brafs Plate L. This keeps them 
 fteady, and at the fame time permits them 
 1 1 be moved to and fro for a thorough Exa- 
 n nation. A 
 
The Double Reflecting Micro fcope. 2 r 
 A little Ivory round Box 5. to hold pieces 
 of Ifinglais for the Sliders. 
 
 6. a fmall Hair Brufh, to wipe any Duft 
 off the GlafTes, or to apply a Drop of any 
 Liquid. 
 
 7. a pair of Nippers, to take up any Ob- 
 ject to be examined. 
 
 The twoMicrofcopes I /hall defcribe next, 
 viz. the Solar, or Camera Obfcura Micro- 
 fcope, and the Micro/cope for Opake Objects, 
 are of a foreign Invention, and but lately 
 known to us. We are, indeed, obliged for 
 them both to a Gentleman of Prufjia, the 
 ingenious Dr. Liberkhun, who when he 
 was in England, about two Years ago, Shew- 
 ed an Apparatus for each of thefe Purpofes, 
 of his own Contrivance and Workmanfhip, 
 to feveral Gentlemen of the Royal Society, 
 and alio to fome Opticians j amongfl whom, 
 Mr. Cuff, againft Serjeants-Inn Gate, in 
 Flcetjlreet, has taken great Pains to improve 
 and bring them to Perfection : and therefore 
 I fhall give a Defcription of them, as made 
 and fold by him. 
 
 C 3 CHAP. 
 
22 Of the Solar y or 
 
 CHAP. VI. 
 
 The Solar ', or Camera Obfcura Microfcope. 
 
 THIS Microfcope depends on the Sun- 
 mine, and mult be made ufeof in a. 
 darken'd Chamber, as its Name implies. 
 
 It is compofed of a Tube, a Looking- 
 glafs, a convex Lens, and Wilson's fingle 
 Pocket Microfcope before defcribed, p. 9. 
 
 The Tube is of Brafs, near two Inches 
 in Diameter, fixed in a circular Collar of 
 Mahogany : which, turning round at plea- 
 fure, in a fquare Frame of the fame Wood a 
 may be adjufled eafily to a circular Hole in; 
 the Shutter of a Window whereon the Sun 
 comes ; in fuch a manner, that no Light 
 can pafs into the Room but through the 
 aforefaid Tube. 
 
 Fattened to the Frame, by Hinges, on 
 the Side that goes without the Window, is 
 a Looking-glafs : which (by means of a 
 jointed Wire coming thro' the Frame, to- 
 gether with a Brafs Pulley, that by the 
 crofiing of a Cat-gut ferves to turn it round) 
 may be moved, either vertically, or horizon- 
 tally, as the Situation of the Sun mall re- 
 quire, to throw its Rays through the Brafs 
 Tube into the darken'd Room. 
 
 The End of the Tube without the Window 
 
 has a convex Lens, to collect the Rays, and 
 
 1 ' bring 
 
Camera Obscura Mkrq/cope. 2 3 
 bring them to a Focus ; and, on the End 
 within the Room, Wilson'* Sitigle Pocket 
 Microfcope mult be (brewed, with the Ob- 
 ject to be examined, applied to it in a 
 Slider. 
 
 The Sun's Rays being directed by the 
 Looking-glafs through the Tube upon the 
 Object, the Image or Picture of the Object 
 will be thrown, distinctly and beautifully, 
 upon a Screen of white Paper, or a white 
 Linen Sheet, placed at fome Diftance to 
 receive the fame ; and may be magnified, to 
 a Size beyond the Imagination of thofe who 
 have not feen it : for the farther off the 
 Screen is removed, the larger will the Ob- 
 ject appear ; inibmuch, that a Loufe may 
 be magnified to the Length of five or fix 
 Feet, or even a great deal more : but it is, 
 indeed, more diitinct, when not enlarged 
 to above half that Size. 
 
 When this Microfcope is employed, the 
 Room mull be render'd as dark as poiTible : 
 for on the Darknefs of the Room, and the 
 Brightnefsof the Sunfhine, depend theSharp- 
 nefs and Beauty of your Image. The Tube 
 and Looking-glais mould alfo be fettled right, 
 before you put on the Microfcope ; the way 
 of doing which is, by turning them about, 
 until the Light becomes reflected in a direct 
 Line through the Tube, and forms upon the 
 Screen a bright Spot exactly round : for the 
 Roundneis of this Spot proves the true Po- 
 C 4 fition 
 
24 Of the Solar, or 
 
 fition of the Inftrument, and that the Mi- 
 crofcope and Object may be then apply'd. 
 
 Within the Tube is a Aiding Drawer, 
 that pulls out more or lefs, as the Object is 
 able to endure the Sun's Heat. Dead Ob- 
 jects may be brought within about an Inch 
 of the Focus of the convex Lens at the End 
 of the Tube without the Window j but the 
 Diftance muft be fhorten'd for living Crea- 
 tures, or they will foon be killed. 
 
 The Body of the Microfcope (after taking 
 out the Lens at the End thereof) muft be 
 fcrewed to a fhort Tube of about one Inch 
 and a half in length, made to flip over the 
 fmall End of the Aiding Drawer ; by which 
 means, the Objects may be brought to their 
 true focal Diftance, which will be known 
 by the Clearnefs and Sharpnefs of their Ap- 
 pearance : they may alfo be turn'd round, 
 without being at all diforder'd. 
 
 The Magnifiers are to be fcrewed to the 
 End of the Microfcope, and the Sliders ap- 
 ply'd in the ufual manner; and, generally 
 fpeaking, the fourth, fifth, or fixth Glafs 
 exhibits the Object beft. 
 
 This Microfcope is the moft entertaining 
 of any, and, perhaps, the moft capable of 
 making Difcoveries, in Objects that are not 
 too opake: as it thews them much larger 
 than can be done any other way. There 
 are alfo feveral Conveniencies attending it, 
 which no other Microfcope can have : for 
 
 the 
 
Camera Obscura Microfcope. 2$ 
 the weakeft Eyes may ufe it without the 
 lead Straining or Fatigue : Numbers of Peo- 
 ple may view any Object together at the 
 fame Time, and, by pointing to the parti- 
 cular Parts thereof, and diicourling on what 
 lies before them, may be able better to un- 
 derftand one another, and more likely to 
 find out the Truth, than when, in other 
 Microfcopes, they muft peep one after an- 
 other, and perhaps fee the Object neither in 
 the fame Light, nor the fame Pofition. Such 
 too as have no Skill in Drawing, may, by this 
 Contrivance, ealily fketch out the exact Fi- 
 gure of any Object they have a mind to pre- 
 ferve a Picture of ; fince they need only faft- 
 ew a Paper upon the Screen, and trace it out 
 thereon either with a Pen or Pencil, as it 
 appears before them. 
 
 It is worth their while, who are defirous 
 to take many Draughts this way, to get a 
 Frame, wherein a Sheet of Paper may be 
 put or taken out at pleafure ; for if the 
 Paper be fingle, the Image of an Object will 
 be ken as plainly almoft on the back as on 
 the fore Side, and by {landing behind the 
 Screen, the Shade of the Hand will not ob- 
 flruct the Light in Drawing, as it muft in 
 fome degree when one ftands before it. 
 
 I mult obferve, that Dr. Liberkhun's 
 Solar Microfcope had no Looking-glafs be- 
 longing to it, and therefore was of ufe a few 
 Hours only in a Day, when the Tube could be 
 I placed 
 
26 • Of the Micro/cope 
 
 placed directly againft the Body of the Sun, 
 and even then not without a good deal of 
 Trouble ; but by this lucky Contrivance of 
 a Looking-glais, the Sun's Rays may be re- 
 flected thro' the Tube, whatever its Height 
 or Situation be, provided it mines at all upon 
 the Window, and that too with much Eafe 
 and Advantage. 
 
 CHAP. VII. 
 
 Of the Micro/cope for Opake Objctfs. 
 
 THIS Microfcope remedies the Inconve- 
 nience of having the dark Side of an 
 Object next the Eye, which has hitherto been 
 an unfurmountable Obstruction to the mak- 
 ing Obfervations on opake Objects with any 
 considerable Degree of Exactnefs or Satis- 
 faction : for in all other Contrivances com- 
 monly known, the Nearnefs of the Inftru- 
 ment to the Object (when GlafTes that mag- 
 nify much are uied) unavoidably overfhadows 
 it fo much as to render its Appearance ob- 
 fcure and undiftinct. And, notwithstanding 
 Ways have been tried to point Light upon 
 an Object, from the Sun, or a Candle, by a 
 convex Glafs placed on the fide thereof : the 
 Rays from either can be thrown upon it in 
 luch an acute Angle only, that they ferve to 
 give a confufed Glare, but are infugicient to 
 
 afford 
 
for Opake Objects. 27 
 
 afford a clear and perfect View of the Ob- 
 ject 
 
 But In this new Microfcope, by means of 
 a concave Speculum of Silver, highly polifh- 
 ed, in whole Center a magnifying Lens is 
 placed, fo direct and ttrong a Light is re- 
 flected upon the Object, that it may be ex- 
 amined with all imaginable Eafe and Plea- 
 fure. 
 
 The Apparatus for this Purpofe (as in the 
 Plate, Numb. IV.) has afforded me more 
 Delight and Satisfaction than I am able to 
 defcribe j and whoever trys it, will I believe 
 join in my Opinion, that he never before 
 (aw an opake Object with fo much Clear- 
 nefs, and in fo perfect and true a manner. 
 
 The feveral Parts o( this Inttrument made 
 cither of Brafs or Silver, are as follows. 
 
 Through the firft fide, A. paffes a fine 
 Screw B. the other End whereof is fattened 
 to the moveable fide C. 
 
 D. is a Nut adapted to the faid Screw, 
 by the turning of which the two fides A. C. 
 are gradually brought together. 
 
 E. is a Spring of Steel, that feparates the 
 faid two fides when the Nut is unferewed. 
 
 F. a piece, of Brafs turning round in a. 
 Socket, whence proceeds a fmall Spring Tube 
 moving upon a Rivet, through which Tube 
 there runs a Steel Wire, one End whereof 
 terminates in a fharp Point G. and the other 
 hath a pair of Flyers H. fattened to it. — The 
 
 Point 
 
28 Of the Micro/cope 
 
 Point and Plyers are to thru ft into or take 
 up and hold any Infect or Object : and either 
 of them may be turned upwards, as fuits 
 your Purpofe be ft, 
 
 I. a Ring of Brafs with a female Screw 
 within it, mounted on an upright piece of 
 the fame Metal, which turns round on a 
 Rivet, that it may be fet at a due Diftance 
 when the leaft Magnifiers are employed. 
 
 This Ring receives the Screws of all the 
 
 Magnifiers. 
 
 K. a concave Speculum of Silver, polim'd 
 as bright as poffible, in the Center of which 
 a double convex Lens is placed, with a pro- 
 per Aperture to look through it. On the 
 Back of this Speculum a male Screw L. is 
 made fit to the Brafs Ring I. to fcrew into 
 the faid Ring at pleafure. 
 
 There are four of thefe concave Specula, 
 of different Depths, adapted to four GlarTes 
 of different magnifying Powers, to be ufed 
 as Objects to be examined may require. The 
 greateft Magnifiers are known by having the 
 leaft Apertures. 
 
 M. a round Obj eel:- Plate, one fide white 
 and the other black, intended to render Ob- 
 jects the more vifible, by placing them, if 
 black on the white, and if white on the 
 black fide. A Steel Spring N. turns down 
 on each fide to make any Object faft : and 
 iffuing from the Object-Plate is a hollow 
 Pipe to fcrew it on the Needle's Point G. 
 
 o. 
 
for Opake ObjcBs. 29 
 
 O. a fmall Box of Brafs, with a Glafs on 
 each fide, contrived to confine any living 
 Object, in order to examine it : this alfo has 
 a Pipe to fcrew upon the End of the Needle 
 G. 
 
 P. a turned Handle of Wood, to fcrew 
 into the Inftrument when it is made ufe 
 of. 
 
 Q^a pair of Brafs Plyers, to take up any 
 Object, or manage it with Convcniency. 
 
 R. a foft Hair Bruih, to clean the GlafTes 
 or Specula, or apply a Drop of any Liquid 
 to the Iiindafs of the Box O. in order to 
 
 o 
 
 view the Animalcula. 
 
 S. a fmall Ivory Box for IfinglafTes, to be 
 placed when wanted in the fmall Braf> Box 
 O. 
 
 When you would view any Object, fcrew 
 the Speculum, with the Magnifier you think 
 beft to ufe, into the Brafs Ring I. Place your 
 Object either on the Needle G. in the Plyers 
 H. on the Object-Plate M. or in the Brafs 
 hollow Box O. as may be mod convenient, 
 according to the Nature and Condition of it: 
 then holding up your Inftrument by the 
 Handle P. look again ft the Light, through 
 the magnifying Lens, and by means of the 
 Nut D. together with the Motion of the 
 Needle, by managing its lower End, the 
 Object may be turn'd about, raifed, or de- 
 prelled, brought nearer the Glafs, or put 
 farther from it, till you hit the true focal 
 
 Distance, 
 
30 Of the Micro/cope 
 
 Diftance, and the Light be feen reflected 
 from the Speculum flrongly upon the Ob- 
 ject : by which means, it will be {hewn in 
 a manner furprizingly diflinct and clear. 
 And for this purpofe, the Light of the Sky, 
 or of a Candle, will anfwer to your Satis- 
 faction. 
 
 This Microfcope is principally intended 
 for opake Objects, but tranfparent ones may 
 alio be viewed by it : obferving only, that 
 when fuch come under Examination, it will 
 not always be proper to throw on them the 
 Light reflected from the Speculum : for the 
 Light tranfmitted through them meeting 
 the reflected Light, may together produce 
 too great a Glare. A little Practice will 
 teach how to regulate both thefe Lights to 
 good Advantage. 
 
 There is F^eafon to expect great Difcove- 
 ries may be made by the Apparatus above 
 defcribed, as Opake Objects are a large Field, 
 but little hitherto examined, by reafon of 
 the great Difficulty in doing it. 
 
 Having given a Defcription of the feveral 
 forts of Microfcopes in ufe amongfl us at 
 prefent, and fhewn what particular Advan- 
 tages may be expected from each, I fhall 
 proceed to inftruct the Ignorant in thefe 
 Things, with all the Clearnefs I can, to find 
 out the magnifying Powers of the GlafTes 
 they make ufe of, and calculate how many 
 
 times > 
 
for Opa&e Objects. 3 1 
 
 times they enlarge the Diameter, the Super- 
 ficies, and the * Cube or folid Square of anv 
 Object under Examination. And this, I 
 perfuade my felf, will be highly fatisfa&orv, ' 
 and induce many People to be fond of this 
 mod delightful and inltructive Study, when 
 the Difficulties they imagined in it are re- 
 moved, and they perceive it to be as eafy as 
 it is pleafant i when they find themfelves 
 able to judge of what they fee, not by meer 
 random Guefs, but by certain and plain- 
 Principles. 
 
 CHAP. VIII. 
 
 To find the Magnifying Power of Glajfes 
 employed in Single Micro/copes. 
 
 TH E Appearance of any Object, as to 
 Magnitude, is according to the Angle 
 it is feen under ; or, in other Words, ac- 
 cording to the Nearnefs it can be brought 
 to the Eye : for the lefs the Diftance it can 
 be viewed at is, the more it will appear en- 
 larged. 
 
 * Some, perhaps, may diflike my fuppofing the Cube of 
 ah Object to be magnified, fince in reality the Superficies 
 only can be feen : but the Neceflity of fuch a Suppofuion will 
 appear plainly in the Progrefs of this Work, when we come 
 to confider the true Size of Microfcopical Objects, by com- 
 paring them with larger Bodies. 
 
 The 
 
32 The Magnifying Power of Glajfes. 
 
 The naked Eye is unable to diftingui/h 
 any Object brought exceedingly near it : 
 but looking through a convex Lens, how- 
 ever near the Focus of that Lens be, there 
 an Object may be diftinctly feen : and the 
 fmaller the Lens is, the nearer will be its 
 Focus, and in the fame Proportion the great- 
 er mud be its magnifying Power. 
 
 From thefe Principles, it is eafy to find 
 the Reafon, why the firft or greater!: Mag- 
 nifiers are fo extremely minute - y and alfo to 
 calculate the magnifying Power of any con- 
 vex Lens employed fingly in a Microfcope. 
 For fuch as the Proportion of the natural 
 Sight to the Focus of the Lens is, fuch will 
 be its Power of magnifying. If the Focus 
 of a convex Lens (for Example) be at one 
 Inch, and the natural Sight at eight Inches, 
 which is the common Standard, an Object 
 may be {ten through that Lens at one Inch 
 diftant from the Eye : and will appear, in its 
 Diameter, eight times larger than to the 
 naked Eye. But as the Object is magnified 
 every way equally, in Length as well as 
 Breadth, we muft fquare this Diameter to 
 know really how much it appears enlarged j 
 and we mall then find, that its Superficies is 
 indeed magnified fixty-four times. 
 
 Again : Suppofe a convex Lens whofe 
 Focus is at one Tenth of an Inch diftant 
 from its Center : In eight Inches there are 
 eighty fuch Tenths of an Inch j and there- 
 fore 
 
The magnifying Power of Glaffes. 3 3 
 fore an Object may be feen through this 
 Lens eighty times nearer than it can diftinct- 
 ly by the naked Eye. It will confequently 
 appear eighty times longer, and eighty times 
 broader, than it does to common Sight ; and 
 as eighty multiplied by eighty makes fix 
 thoufand and four hundred, fo many times 
 it really appears magnified. 
 
 To go one ftep firther : If a convex Glafs 
 be fo fmall, 'that its Focus is no more 
 than one twentieth of an Inch diftant j we 
 (hall find, that eight Inches, the common 
 Distance of Sight, contains an hundred and 
 fixty of thefe twentieth Parts ; and, in con- 
 fequence, the Length and Breadth of an 
 Object, when ken through fuch Lens, will 
 each be magnified an hundred and fixty 
 times ; which, multiplied by an hundred 
 and fixty, to give the Square, will amount 
 to twenty-five thoufand fix hundred : and 
 fo many times, it is plain, the Superficies of 
 the Object mult appear larger than it does 
 to the naked Eye at the Diflance of eight 
 Inches. 
 
 Therefore, in a fingle Microfcope, to 
 learn the magnifying Power of any Glafs, 
 no more is neceffary than to bring it to its 
 true Focus j the exact Place whereof will 
 be known, by an Object's appearing perfect- 
 ly diitinct and fharp when placed there. 
 Then with a Pair of fmall Compaffes, mea- 
 
 D fure, 
 
> 4 The Magnifying Power of Glafj'es. 
 Cure, as nearly as y )u can, the Dil ranee from 
 the Center of the Glafs to the Object you 
 was viewing, and afterwards applying the 
 CompalTes to any Ruler with a Diagonal 
 Scale of the Parts of an Inch marked on it, 
 you will eafily find how many Parts of an 
 Inch the faid Diftance is : When that is 
 known, compute how many times thofe 
 Parts of an Inch are contained in eight 
 Inches, the common Standard of Sight, and 
 that will give you the Number of times the 
 Diameter is magnified : fquaring the Dia- 
 meter will give you the Superficies ; and if 
 it be an Object whofe Depth or whole Con- 
 tents you would learn, multiplying the Su- 
 perficies by the Diameter will mew the 
 Cube or Bulk. 
 
 The Superficies of one Side only of an 
 Object can be feen at one View ; and to 
 compute how much that is magnified is 
 moft commonly fufficient. But fometimes 
 it is fatisfadtory to know how many minute 
 Objects are contained in a larger : as, fup- 
 pofe, for Inftance, I defire to know, how 
 many Animalcules would make up the Big- 
 nefs of a Grain of Sand : To aniwer this, 
 the Cube as well as the Superficies of the 
 Animalcules muft be taken into the Ac- 
 count ; as will be (hewn in the next Chap- 
 ter. 
 
 As 
 
To be placed after Page 34. 
 
 *A TABLE of the MAGNIFYING POWERS of CONVEX GLASSES 
 
 employed in Single Microscopes, according to the Diftance of their Focus : 
 
 Calculated by the Scale of an Inch divided into an Hundred Parts : 
 
 Shewing how many times the Diameter, the Superficies, and the Cube of an Object is magnified, 
 
 when viewed through fuch Glajfes, to an Eye whofe natural Sight is at Eight Inches, 
 
 or Eight Hundred of the Hundredth Parts of an Inch. 
 
 Magnifies 
 the Dia- 
 meter , 
 
 Magfiifies 
 the Super- 
 ficies, 
 
 Magnifies the 
 Q\xbtof anOb- 
 
 
 r r> or so ' 
 
 16 
 
 256 
 
 4,096 
 
 
 X 
 
 };> or 40 
 -hi or 3° 
 
 20 
 26 
 
 400 
 676 
 
 8,000 
 
 *7>57 6 
 
 . 
 
 
 j, or 20 
 
 40 
 
 1,600 
 
 64,000 
 
 
 
 15 
 
 53 
 
 2,809 
 
 148,877 
 
 
 
 14 
 
 57 
 
 3> 2 49 
 
 l8 5> 1 93 
 
 
 
 *3 
 
 •3 61 
 
 3>7 21 
 
 226,981 
 
 
 
 1 2 
 
 ~ 66 
 
 4>35° 
 
 287,496 
 
 
 The Focus of 
 a Glafs at ^ 
 
 1 1 
 
 io, or 10 
 9 
 
 •8 72 
 
 CO 80 
 
 1 88 
 
 5> l8 4 
 6,400 
 
 7>744 
 
 373> 2 4 8 
 
 512,000 
 
 681,472 ! 
 
 > Times. 
 
 
 8 
 
 13 1 00 
 
 10,000 
 
 1,000,000 
 
 
 
 7 
 
 1 ,J 4- 
 
 1 2,996 
 
 1,481,544 
 
 
 
 6 
 
 K ^33 
 
 17,689 
 
 2 >35 2 > 6 37 
 
 » 
 
 
 L X or 5 
 
 1 60 
 
 25,600 
 
 4,096,000 
 
 
 
 4 
 
 200 
 
 40,000 
 
 8,000,000 
 
 
 
 3 
 
 266 
 
 70,756 
 
 18,821,096 
 
 
 
 fo 3 or 2 
 
 400 
 
 160,000 
 
 64,000,000 
 
 
 ~ 
 
 1 . 
 
 8co 
 
 640,000 
 
 I 512,000,000. 
 
 
 % The grea tell Magnifier in Mr. Leeuw en hoek's Cabinet of Microfcopes, prefented to the Royal Society, has its 
 Focus, as nearly as can well be meafured, at one Twentieth of an Inch Diftance from its Center, and confequentl/ 
 magnifies the Dia?neter of an Objecl 160 times, and the Superficies 25,600. But the greateft Magnifier in Mr, Wi l son's 
 Single Microfcopes, as they are now made, has ufually its Focus at no farther Diftance than about the Fiftieth Part of 
 «a Inch ; whereby it has a Power of enlarging the Diameter of an Object 400, and its Superficies j 60,000 times. 
 

 
 
 
 
 
 
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 3gnifier in Mr. L 
 can well be mea 
 ter of an Objecl 1 
 as they are now 
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 J The greateft 
 Focus, as nearly a 
 magnifies the Dia 
 Single Microfcope 
 est Inch ; whereb 
 
TV//// 
 
Tbe Magnifying Power o/G/affes. 35 
 
 As this Treatife is chiefly intended for 
 thofe who underftand but little of fuch Mat- 
 ters, it may neither be needlefs, nor unac- 
 ceptable, to give a Table of the magnifying 
 Powers of the convex Glades commonly 
 ufed in fingle Microfcopes, according to their 
 different Focus : whereby, upon meafuring 
 what the belt. Diftance from the Glafs to 
 view the Objecl is, its Power of magnifying 
 the Diameter, the Superficies, and the Cube 
 of an Object will be found in one Line. 
 
 See the Table *. 
 
 As this Table is given in round Num- 
 bers, it is fo clear and eafy, that I believe 
 whoever can but divide and multiply a few 
 Figures will readily underftand it. 
 
 I have taken no Notice of any Magnifier 
 whole Focus is at a greater Diftance than the 
 half of an Inch ; becaufe Glades that mag- 
 nify lefs than that, may very eafily be calcu- 
 lated by the Rules above laid down : Nor, 
 when I come to the greateft Magnifiers, have 
 I mentioned any of a fhorter Focus than 
 the one hundredth part of an Inch j fince it 
 is fo difficult to grind a Lens to a Smallnefs 
 beyond, or even fo minute as this, that per- 
 haps few of my Readers may ever meet with 
 fuch an one. And though Globules of Glafs 
 may be melted fo extreamly little, as to 
 have their Focus at not half this Diftance, 
 D 2 and 
 
36 The Magnifying Power o/G/aJJes. 
 
 and confequently their magnifying Powers 
 prodigioufly greater ; the ufe of them is fo 
 troublefome, and attended with fuch want 
 of Light, fuch Undiftinclnefs and Uncertain- 
 ty, that indeed they are of very little Ser- 
 vice. 
 
 The magnifying Powers of the Glafles 
 employed in Wilson's Pocket Micro/cope, 
 and alfo of thofe belonging to the opake Mi- 
 crolcope, are to be calculated in the forego- 
 ing Manner. And as People will, no doubt, 
 be pleafed to know certainly what the Pow- 
 ers of their Glafles are, and confequently 
 what may be expected from them, it would 
 be much better if the Micro/cope -Makers 
 would grind their Glafles according to fome 
 fettled Standard, and not work by guefs, as 
 they ufually do at prefent, whereby no two 
 Sets of Magnifiers can be fuppofed exactly 
 alike. Such a Standard, which would afford 
 a very ufeful Set of Glafles, magnifying one 
 more than another in due Degrees, is, I 
 think, as follows. 
 
 
 
 %%$£ 
 
 The 
 
The Magnifying Powers ofGlafes. 37 
 
 The FOCAL DISTANCES of 
 
 Six Magnifiers for Mr. Wilson's 
 Pocket Microfcopc. 
 
 * 
 
 Magnifies [ Magnifies the 
 the Diam. Superficies, 
 
 "\ 
 
 ;" j'o» or 2 1 #\ — 400^ 
 
 c 
 
 > 
 
 Dift. of 
 the Fo-j 
 
 t'o> or 5 
 
 •= — 160 
 
 c 
 
 <tr ICO 
 
 cusat--- 16 I 
 
 tV, or 3° 
 L h or 5° J 
 
 ■50 
 -26 
 
 
 — 160,000'' 
 
 2J, 60O 
 
 — I0,000 
 
 -i6j 
 
 — 2,500 
 
 - 676 
 
 — 256J 
 
 X§ 
 
 flfe FOCAL DISTANCES 
 Four Magnifiers yor /Z?^ Micro/cope 
 for Opake Objects. 
 
 Magnifies the 
 Superficies, 
 
 of 
 
 $ 
 1 
 
 2 
 3 
 
 4 
 
 ico pts. of 
 an Inch, 
 
 Dirt, of 
 the Fo- 
 cus at— 
 
 Magnifies 
 the Diam. 
 
 The magnifying Power of the Solar Mi- 
 crofcope mud be calculated in fomewhat a 
 different Manner. For here, the Difference 
 between the Focus of the Magnifier, and 
 the Diftance of the Skreen, or Sheet where- 
 on the Image of an Object is caft, is the Pro- 
 portion of its being magnified. Suppofe, for 
 inftance, the Lens made ufe of has its Focus 
 D 3 as 
 
38 The Magnifying Power of Glajfes. 
 
 at half an Inch, and the Skreen he placed 
 at the Diftance of five Feet : The Object 
 will then appear enlarged in the Proportion 
 of five Feet to half an Inch : And as in five 
 Feet there are one hundred and twenty half 
 Inches, the Diameter will be magnified one 
 hundred and twenty Times, which multi- 
 plied by one hundred and twenty, (hews the 
 Superficies to be magnified fourteen thou- 
 fand and four hundred Times : and by put- 
 ting the Skreen at farther Diftances you 
 may magnify your Objects to almoft what 
 Size you pleafe. But I would advife all 
 who ufe this Sort of Microfcope, to re- 
 gard Diftinctnefs more than Bignefs, and 
 place the Skreen juft at that Diftance 
 where the Object is fctn moft fharp and 
 clear. 
 
 #% 
 
 CHAP, 
 
[ 39 ] 
 
 CHAP. IX. 
 
 Of the magnifying Power of GJafes in the 
 double Microfcope. 
 
 I Should now (hew the Method of com- 
 puting the magnifying Power of our 
 double Microfcope, as I have done of the 
 fingle ones : but a Calculation of the Powers 
 of three combined GlafTes, would appear fo 
 intricate and unintelligible to People unac- 
 quainted with Optics, ( for whofe Service 
 chiefly I intend this Treatife) that I believe 
 they will readily excufe my perplexing them 
 with it : and as for the learned in that Sci- 
 ence, they probably will be better pleated to 
 calculate for themielves. 
 
 The double reflecting Microfcope, defcri- 
 bed p. 1 6. is the only Inftrument at prefent 
 made amongft us for this Purpofe, wherein 
 fuch a Combination of GlafTes is employed. 
 Here, indeed, the magnifying Power of the 
 Object- Lens is greatly increafed by the Ad- 
 dition of two Eye-glafles ; but as no Object- 
 Lens can be ufed with them of fo minute a 
 Diameter, or that magnifies of itfelf near fo 
 much as the Lcnfes we can ufe alone, upon 
 the whole, the Glafles of this double Micro- 
 fcope magnify little or nothing more than 
 thofe of Mr. Wi lson's fingle one. And 
 tlie fame Table which (hews the Powers of 
 D 4 the 
 
40 The Size of ObjecJs 
 
 l he GlaiTes belonging to that Microfcope, 
 may ferve for thefe alio. For the fir/l Glafs, 
 JctCndGlaJs, Sec. of either Microfcope mag- 
 nify pretty much alike ; and the chief Ad- 
 vantage arifing from a Combination of Glaf- 
 fes, is, the fight of a larger Field or Portion 
 of an Object, magnified in the fame Degree. 
 
 CHAP. X. 
 
 To find cut the real Size of Objects feen 
 by Microfcopes. 
 
 r T"^ H O' by the preceding Directions the 
 JL magnifying Powers of Microfcope- 
 Glaffes may eafily be underflood, it will flill 
 remain uncertain, (if the Objects we examine 
 are exceedingly minute) what the real Big- 
 nefs of them is. For though we may know 
 they are magnified fo many thoufand Times, 
 we can make by that Knowledge but a very 
 imperfect Computation of their natural and 
 true Size ; nor can we, indeed, come to any 
 certain Conclufion as to that, but by the 
 Mediation of fome larger Object, whole 
 Dimennons we really know. For as Bulk 
 itfelf is meerly comparative, the only Way 
 we can judge of theBignefs of any thing, is, 
 by comparing it with fomething elfe : and 
 finding out how many times the leffer is 
 contained in the larger Body. To do this 
 
 in 
 
view 1 J by Microfcopcs. 41 
 
 in Microfcopical Objects, feveral ingenious 
 Methods have been contrived ; of which, 
 fuch as are come to my Knowledge, and 
 are plain and practicable, I (hall lay before 
 the Reader. 
 
 Mr. Leeuwenhoek's Way of comput- 
 ing the Size of Salts in Fluids, of the Ani- 
 malcules in Semine ma/culino, in Pepper- 
 Water y &c. was by comparing them with 
 the Bignefs of a J Grain of Sand j and his 
 Calculations were made in the following 
 Manner. 
 
 He viewed through his Microfcope a An- 
 gle -j- Grain of Sand, which we'll fuppofe to 
 be magnified as the round Figure ABCD. 
 Then obferving an Animalcule fwimming, 
 or running acrofs it, or coming near it, 
 (which we'll imagine to be of the Size 1.) 
 coniidering and meafuring this bv his Eye, 
 he concludes, that the Diameter of this Ani- 
 malcule is lefs, by a twelfth Part, than the 
 Diameter of the Grain of Sand : confe- 
 
 \ N. B. It is proper to inform the Reader, that where - 
 ever, in this Treatife, Microfcopical Objects are compared 
 with a Grain of Sand, which commonly was the Meafurc 
 Mr. Leeu \v en hoek made ufe of, we muft underftand it to 
 mean a Grain of coarfe Sea-Sand (ufually called Scout ing- 
 Sand) which is equal in Bignefs to feveral Grains of our 
 common Inland Houfe-Sand, or Writing-Sand : But to make 
 our Calculations ftill more certain, we muft fuppofe them of 
 fuch a Size, that an Hundred of them, placed in a Row, 
 fhall extend an Inch in Length. 
 
 f Vide Leeu wen. Experim. & Contcmpl. Tom. IV. 
 pag. 23. 
 
 quently 
 
42 The Size of Objetts 
 
 quently, according to the common Rules, 
 the Superficies of the Grain of Sand is one 
 hundred forty four times, and the whole 
 Contents thereof one thoufand feven hun- 
 dred and twenty eight times larger than this 
 Animalcule. 
 
 Suppofe, again, that he fees among thefe 
 another and fmaller Species of Animalcules ; 
 one of which [2.] he likewife meafures with 
 his Eye, by the help of a good Microfcope ; 
 and computes its Diameter to be five times, 
 but, to be within compafs, he reckons it 
 only four times lefs than the former Animal- 
 cule 1. According then to the foregoing 
 Rules, the Diameter of this will be lixteen, 
 and the whole Bulk fixty-four times lefs 
 than the Animalcule 1. 
 
 If farther, upon a nicer View, he difco- 
 vers a third Sort of Animalcule [3.] fo ex- 
 ceedingly minute, that, examining it in the 
 former Manner, he concludes that the Dia- 
 meter thereof is ten times fmaller than the 
 fecond fort : it will then follow, that a 
 thoufand of thefe are but equal in Bignefs 
 to one of that fecond fort. 
 
 The firft fort multiplied by the fecond, 
 and the fecond by the third, will plainly de- 
 rnonftrate how many of this third and mi- 
 nuteft fort are requifite to make up the 
 Bulk of a (ingle Grain of Sand: the Procefs 
 ei which is as follows. 
 
 Firft 
 
Pag. 4/. 
 
 jPlatoK 
 
 / . Trvelvt rim&f fejj 6/uz>n t/isJ^uvme&r B. C 
 
 ^ 1- 
 
 H 1- 
 
 -I 1- 
 
 JFiM>r ti/m&f Ids tAafi £/ieJ)ia,meter<7f3f°f. 
 
 • Ten tvm&f k$ t/uwi (AeJ)uwneter cfjRF.2. 
 
. 
 
viewed by Micro/copes. 43 
 
 pirft fort, 1. whofe Diameter is lefs 
 than that of a Grain of Sand. 
 
 12 times 
 12 
 
 144 
 
 Of the firft fort, 1,728 in a Grain of Sand. 
 
 Second fort, 2. whofe Diameter is lefs than 
 that of the firft fort. 
 
 4 times 
 
 4 
 16 
 _4 
 64 in one of the firft fort. 
 
 Third fort, 3. whofe Diameter is lefs than 
 that of the fecond fort, 
 
 10 times 
 10 
 
 100 
 10 
 
 1000 in one of the 2d fort. 
 
 1728 
 
44 ¥be Size of Objefis 
 
 1728 of the firft fort in a Gj*. of Sand. 
 64 of the 2d fort in one of the ift. 
 
 h »i 1 — 
 
 69I2 
 IO368 
 
 1 10,592 of the 2d fort in a Gr. of Sand. 
 1000 of the 3d fort in 1 of the 2d. 
 
 1 10,592,000 of the 3d fort in a Grain of Sand. 
 
 After this manner, the comparative Size 
 of all forts of Objects may very eafily be 
 computed, only fubftituting (for fuch as are 
 lefs minute) a fmall Seed, or fome other 
 Body whofe Size we are well acquainted 
 with, in the room of a Grain of Sand. 
 And, particularly, by the Solar Microfcope, 
 our Calculations may be made with great 
 Certainty ; fmce the Image of the Object 
 enquired after, and of the Grain of Sand, 
 the fmall Seed, or whatever elfe is thought 
 proper to compare with it, may be really 
 meafured by a Ruler, or a Pair of CompafTes, 
 and the Difference of their Diameters moil 
 exactly found. 
 
 The Method Mr. Hooke made ufe of, to 
 know how much an Object appears magni- 
 fied, I fhall give in his own Words. 
 
 tl Having (fays he) rectified the Microfcope, 
 " to fee the defired Object through it very 
 u diftinctly j at the fame time that I look 
 
 " upon 
 
viewed by Microfcopes. 45 
 
 t( upon the Object through the Glafs with 
 " one Eye, I look upon other Objects at 
 " the fame Diftance with my other bare 
 tc Eye : by which means I am able, by the 
 " Help of a Ruler divided into Inches and 
 il fmall Parts, and laid on the Pedeftal of 
 " the Microfcope, to cart: as it were the 
 t{ magnified Appearance of the Object upon 
 " the Ruler, and thereby exactly to mea- 
 " fure the Diameter it appears of through 
 " the Glafs ; which being compared with 
 " the Diameter it appears of to the naked 
 M Eye, will eafily afford the Quantity of its 
 11 being magnified." — 'This, for Multitudes 
 of Objects, is a ready and good Way ; and I 
 can declare from my own Experience, that 
 a little Practice will render it exceeding eafy 
 and pleafant. 
 
 Another very curious Way for this Pur- 
 pofe,is defcribed by the ingenious Dr. Jurin, 
 in the 45th Page of his Pbyfico-mathematical 
 Differtations ; the Manner whereof is thus: 
 Wind a piece of the fineil Silver Wire you 
 can get a great many times about a Pin, or 
 fome other fuch (lender Body, fo clofely as 
 to leave no Interval between the Wire- 
 Threads ; to be certain of which they mufh 
 be carefully examined with a Glafs. Then, 
 with the Points of a fmall Pair of CompafTes, 
 meafure exactly what Length of the Pin the 
 Wire covers : and applying the Companies 
 with that Meafure to a diagonal Scale of 
 
 Inches, 
 
46 The Size of ObjeSfi 
 
 Inches, you'll find how much it is : after 
 which, by counting the Number of Wire- 
 Rounds contain'd in that Length, you'll ea- 
 fily difcover the real Thicknefs of the fingle 
 Wire. This being known, cut it into very 
 fmall Pieces, and when you examine an 
 Object, if it be opake, ftrew fome of thefe 
 Wires upon it ; if tranfparent, under it ; 
 and with your Eye compare the Parts of the 
 Object with the Thicknefs of fuch Bits of 
 Wire as lye faired: to your View. 
 
 By this Method Dr. Jur in obferved, that 
 four Globules of human Blood would gene- 
 rally cover the breadth of a Wire, which 
 he had found to be T £ T th part of an Inch ; 
 and confequently that the Diameter of a fin- 
 ele Globule was wfestk part of an Inch. 
 Which was alfo confirmed by Mr. Leeu- 
 wenhoek's Obfervations upon human 
 Blood, made with a piece of the fame Wire, 
 fent to him by Dr. Jur in. Vide Philofoph. 
 Tranf. N°' 377. 
 
 Mr. Martin, in his Optics, gives ano- 
 ther way, fufficiently eafy and ready on all 
 Occafions. On a circular Piece of Glafs, 
 let a Number of parallel Lines be drawn t 
 carefully with the tine Point of a Diamond, 
 at the Diftance of one fortieth Part of an 
 Inch from each other. If this be placed in 
 the Focus of the Eye-glafs of a Microfcope, 
 the Image of the Object will be fctn upon 
 thule Lines, and the Parts thereof may be 
 
 compared 
 
"oieivd by Micro/copes. 47 
 
 compared with the Intervals, whereby its 
 true Magnitude, or Dimenfions, may be ve- 
 ry nearly known : for the Intervals of thefe 
 Lines, though fcarce difcernible to the naked 
 Eye, appear very large through the Micro- 
 fcope. A Contrivance of this Kind mav 
 alio be invented for fueh Micro fcopes, as a 
 Glafs cannot be apply'd to in the above man- 
 ner, by placing it under or behind the Ob- 
 ject, which will anfwer the fame Purpofe. 
 
 Hereby it will be eafy to find what pro- 
 portion an Object, or any Part thereof, bears 
 to an Interval between two Lines, and then 
 determine it in Parts of an Inch : for if the 
 Width of an Object appears juft one Inter- 
 val, we (hall know it to be Jul! one fortieth 
 Part of an Inch ; if half an Interval, the 
 eightieth ; if a quarter of an Interval, the 
 one hundred and lixtieth ; if one fifth, only 
 the two hundredth Part of an Inch. 
 
 Dr. Smith has an Invention akin to 
 this, for taking exact Draughts of Objects, 
 viewed in double Microfcopes : for he ad- 
 vifes, to get a Lattice made with fmall fil- 
 ver Wires, or fmall Squares drawn upon a 
 plain Glafs by the Strokes of a Diamond, 
 and to put it into the Place of the Image 
 form'd by the Object-Glafs. Then, by 
 transferring the Parts of the Object feen in 
 the Squares of the Glafs or Lattice upon h- 
 milar correfponding Squares drawn on Pa- 
 per, the Picture thereof may be exactly taken. 
 1 There 
 
48 The Area of ObjeSfs. 
 
 There are fome other forts of Microme- 
 ters, or Inventions for meafuring the fmall 
 Objects feen in Micro fcopes ; but as they are 
 more complex and difficult, I mall not fwell 
 this Volume with them. 
 
 CHAP. XI. 
 
 Of the Area or Portion of an Otyz&feen. 
 
 HPH E vifible Area, Field of View, or 
 JL Portion of any Object feen through a 
 Microfcope, is in Proportion to the Diame- 
 ter and Area of the Lens made ufe of, and 
 its Power of magnifying, and may be there- 
 by determined : fince, if the Lens is ex- 
 treamly fmall, it magnifies a great deal, and, 
 confequently, a very minute Portion only of 
 an Object can be diflinguimed through it. 
 For which reafon the greateft Magnifiers 
 never fhould be employed but for the moft 
 
 minute Objects. This Confederation will 
 
 direct how to fuit the Magnifiers to the Size 
 of the Objects to be examined, which is of 
 the utmoil: Confequence in Microfcopical 
 Obfervations ; and may ferve to rectify the 
 Miffake of abundance of People unexperi- 
 enced in Glaffcs, who, upon feeing a Mite 
 or a Louie greatly magnified, are apt to cry 
 out, with much Surprize, O that we had a 
 
 Cricket, 
 
I'he Area of ObjeZs. 49 
 
 Cricket, a Frog, or fome fuch Creature j 
 how finely that would appear ! Whereas, 
 in truth, fuch large Objects would intirely 
 cover the Lens, and could not be feen at all. 
 
 Microfcopes very happily ailifr. us when 
 Objects are fo {mall as to evade our Sight ; 
 but it would be trifling and unneceffary to 
 employ theru on fuch large Things as we 
 can fee without their Help. 
 
 I mall not trouble the Unfkijful with per- 
 plexing Calculations about the Area or Field 
 of Objects iecn by each Magnifier, but give 
 this fiiort Rule in general, that it differs not 
 greatly from the Size of the Lens made ufe 
 of, and that the Whole of any Object, much 
 beyond that Size, cannot conveniently be 
 viewed through it. 
 
 There is fome Difference, as to the vifible 
 Area of an Object, between fingle and dou- 
 ble Microfcopes ; for the double /Lew a lar- 
 ger Portion of it than the (ingle, tho' mag- 
 nify 'd as much. 
 
 Having (hewn the Structure and Towers 
 of Microfcopes, I proceed now to defcribe 
 the Manner of chufing, preparing, and ap- 
 plying Objects to tnem. 
 
 E C II A P. 
 
[ 5° ] 
 
 C II A P. XII. 
 
 Of Oh; efts In general. 
 
 P Roper Objects to be examined by ML 
 crofcopes, are, (as Mr. Hoc ice very ju- 
 dicioufly diftinguimes) " exceeding fmall Bo- 
 '* dies, exceeding fmall Pores, or exceeding 
 " jmall Motions ." 
 
 Exceeding fmall Bodies, muft either be 
 the Parts of larger Bodies, or Things the 
 Whole whereof is exceedingly Minute ; fuch 
 as fmall Seeds, Infects, Sands, Salts, &c. 
 
 Exceeding fmall Pores, are the Interfa- 
 ces between the folid Parts of Bodies, as in 
 Stones, Minerals, Shells, &e. or the Mouths 
 of minute VefTels, fuch as the Air-VefTels 
 in Vegetables, the Pores in the Skin, Bones, 
 cV. of Animals. 
 
 Exceeding fmall Motions, are the Move-" 
 ments of the feveral Parts or Members of 
 minute Animals, or the Motion of the Fluids 
 contained either in animal or vegetable 
 Bodies. 
 
 Under one or other of thefe three Heads 
 alnftof! every thing around us affords Matter 
 of Examination, and may conduce both to 
 our Amufement and Inftruction j as I hope 
 more particularly to fhew. 
 
 Many 
 
Of Objects in general. 5 1 
 
 Many, even of thofe who have purchas'd 
 Microfcopes, are fo little acquainted with 
 their general and cxtenfive LJferulnefs, and To 
 much at a Lois for Objects to examine by 
 them ; that after diverting thcmfelves and 
 their Friends, fome few time?, with what 
 they find in the Sliders bought with them, 
 or two or three more common Things, the 
 Microfcopes are hid alide as of little farther 
 Value: and, a Suppofition that this mud be 
 the Cafe, prevents many Others from buying 
 them ; whereas, among all the Inventions 
 that ever rppeared in the World, none can 
 perhaps be found {o conftantly capable of en- 
 tertaining, improving, and fatisfving the Mind 
 of Man.— To evince this, and excite thofe 
 whole Time and Circum fiances permit, to 
 this delightful Study, is the Intention of my 
 Writing ; and, as Curiofity, the univerfal Paf- 
 fion of Mankind, may this way continually 
 be gratified, I hope I mall not write in vain. 
 And if I can hereby induce any to pafs thofe 
 leifure Hours agreeably and ufefully, in con- 
 templating the Wonders of the Creation, 
 which otherwife would be fpent in tirefome 
 Idlenefs, or, perhaps, fome fimionable and 
 expenlive Vice, I ihall think thefe Sheets 
 very happily bellowed. 
 
 E 2 CHAP, 
 
[ 5^ I 
 
 CHAP. XIII. 
 
 Of examining Objects. 
 
 A N Examination of Objects, in order to 
 j, 1l di!cover Truth, requires a great deal 
 of Attention, Care, and Patience, together 
 with fome confiderable Skill and Dexterity 
 (to be acquired by Practice chiefly) in the 
 preparing, managing, and applying them to 
 the Microfcope. What little Knowledge in 
 thefe Matters I may have gained, either 
 from the Accounts of others, or my own 
 Experience, after being converfant many 
 Years therein, I (hall readily communicate : 
 in hopes my Pains may clear the Way to 
 Dil'coveries that will prove of Confequence 
 to the World, and render this Study both 
 deiirable and eafy. 
 
 When any Object comes to be examined, 
 the Size, the Contexture, and Nature of it 
 fhould be duly confidered j in order to apply it 
 to fuch GlafTes and in fuch a Manner as may 
 fhew it beft. The nrfl Step towards this, 
 conrtanvly mould be, to view it through a 
 Magnifier that can take in the Whole at 
 once : for by oblerving how the Parts lie as 
 to one another, we (hall find it much eafier 
 to examine and judge of them feparately, if 
 there be occaiion.— - After having made our- 
 felves acquainted with the Form of the Whole, 
 
 we 
 
Of examining Objects. 53 
 
 wc may divide it as we pleafe, and the 
 fmaller the Parts into which it is divided, 
 the greater muft be the Magnifiers where- 
 with to view them. 
 
 The Traniparency or Opakencfs of an 
 Object mull: alio be well regarded, and the 
 GlafTes made ufe of, mud be accordingly 
 fuited thereto ; for a tranfparent Object wiil 
 bear a much greater Magnifier than one that 
 is opake ; iince the Nearnefs a Glafs that 
 magnifies much mud: be placed at, una- 
 voidably darkens an opake Object, and pre- 
 vents its being feen, unlets by the Microlcopc 
 on Purpofeforfuch Subjects, defcribedpag. 26. 
 IV loft Objects, however, become tranfparent 
 by being divided into extrcamly thin or mi- 
 nute Parts. Contrivance therefore is necef- 
 fary, to reduce them into fuch Thinnefs or 
 Smallnefs, as may render them molt fit for 
 Examination. 
 
 The Nature of the Object, whether it be 
 alive or dead, a Solid or a Fluid, an Ani- 
 mal, a Vegetable, or a mineral Subftance, 
 mull likewife be confidered, and all the 
 Circumftances of it attended to, that we may 
 apply it in the mod: convenient Manner. If 
 it be a living Animal, care mult be taken to 
 fqueeze, hurt, or difcompofe it as little as 
 pofTible, that its right Form, Pofture and 
 Temper may be difcovered. If a Fluid, and 
 too thick, it muft be thinned with Water : 
 if too thin, we fhould let lbme of its watery 
 E 3 Parts 
 
^4 Of examining Objects. 
 
 Parts evaporate. Some Subftances are fitted: 
 for Qbfervation when dry, others ae;ain when 
 moiftened •, ibme when frefh, and ibme after 
 being kept a while. 
 
 Light is the next Thing to be taken care 
 of, for on this the Truth of all our Exami- 
 nation depends ; and a very little Experience 
 will fhew, how different Objects appear in 
 one Polition and Kind of it, to what they 
 do in another. So that we mould turn them 
 every Way, and view them in every Degree 
 of Light, from Brightnefs even to Obfcurity; 
 and in all Pofitions to each Degree ; till we 
 are certain of their true Form, and that we 
 are not deceived. For, as Mr. Hooke 
 fays, in many Objects it is very difficult to 
 diftinguifh between a Prominency and a 
 Depreffion ; between a Shadow and a black 
 Stain ; and in Colour, between a Reflection 
 and a Whitenefs. The Eye of a Fiy, for 
 Example, in one kind of Light appears like 
 a Lattice drilled through with Abundance 
 of Holes: in the Sun-fhine, like a Surface 
 covered with golden Nails : in one Pofuion, 
 like a Surface covered with Pyramids, in 
 another with Cones, and in other Poikions of 
 quite other Shapes. 
 
 The Degree of Light mud be duly fuit- 
 ed to the Object ; which, if dark, will be 
 feen Deft in a full and ftrong Light ; but if 
 very tranfparent, the Light ihould be prop-or- 
 tionably weak : for which ReaJbn there's a 
 
 Contri- 
 
Of examining Objects. 55 
 
 Contrivance, both in the fingle and double 
 Microlcope, to cut off abundance of its Rays, 
 when fuch transparent Objects are examin'd 
 by the greateft Magnifiers. 
 
 The Light of a Candle, for many Objects, 
 and efpecially fuch as are exceedingly minute 
 and tranfparent, is preferable to Day-light ■> 
 and for others Day-light is beft : I mean the 
 Light of a bright Cloud. As for $uh-{hine. 
 
 DO [ 
 
 it is reflected from Objects with fo much 
 Glare, and exhibits fuch gaudy Colours, 
 that nothing can be determined by it with 
 Certainty : and therefore it's to be account- 
 ed the worll: Light that can be had. 
 
 This Opinion of Sun-ihine muft nor, 
 however, be extended to the Solar Micro- 
 lcope, which cannot be ufed to Advantage 
 without its brighteft Light ; for, in that 
 Way, we fee not the Object itielf whereon 
 the Sun-fhine is cait, but only the Image or 
 Shadow of it exhibited upon a Skreen ; and, 
 therefore, no Confufion can arife by the 
 glaring Reflection of the Sun's Rays from 
 the Object to the Eve, which is the Cwic 1:1 
 other Microfcopes. But then, in that So- 
 lar Way, we muft reft contented with view- 
 ing the true Form and Shape of an Object, 
 without expecting to find its natural Colour, 
 fmee no Shadow can pofiibly wear the Co- 
 ]'Mir< of the Body it reprefents. 
 
 E 4 C H A P 
 
[ 56 ] 
 
 CHAP. XIV. 
 
 Of preparing and applying Objects. 
 
 MOST Objects require fome Manage- 
 ment, in order to bring them proper- 
 ly before the GlaiTes. If they are flat and 
 
 transparent, and fuch as will not be injured 
 by Prefllire, the belt. Method is to inclofe 
 them in Sliders, between two Mufcovy Talcs 
 or Ifiu^lafs. This Way the Feathers of 
 Butterflies, the Scales of Fifties, the Farina; 
 of Flowers, &c. the feveral Parts, and even 
 whole Bodies of minute Infects, and a 
 thoufand other Things, may very conveni- 
 ently be preferv'd. Every curious Obferver 
 will therefore have them always ready to 
 receive any accidental Object, and fecure it 
 for future Examination ; and a Dozen or 
 two of thefe Sliders, judiciouily furnimed, 
 are a fine natural Hiflory, where we may 
 read delightful LefTons of the high Perfecti- 
 on of God's Works, and his Wifdom in 
 their Contrivance. 
 
 In making a Collection of Objects, the 
 Sliders fhoulcl not be filled promifcuoufly, 
 but Care taken to fort the Objects according 
 to their Size and Tranfparency: in fuch man- 
 ner, that none be put together in the 
 fame Slider, but what may properly be ex- 
 amined by the fame Magnifier: and then 
 2 the 
 
Of preparing and applying Objects. 57 
 
 the Slider mould be mark'd with the Num- 
 ber of the Magnifier its Objects are fitteft 
 for : that is, the moft tranfparent, or mi- 
 nuted Objects of all, which require the firft 
 Magnifier to view them by, mould be pla- 
 ced in a Slider, or Sliders mark'd with Num- 
 ber I. Thofe of the next Degree in Sliders 
 mark'd with Number II. and fo of the reft. 
 This Method will lave abundance of Time 
 and Trouble in (Lifting the Magnifiers, 
 which, without fuch Sortment, muft perhaps 
 be done two or three Times in overlooking 
 a fingle Slider*. The Numbers mark'd up- 
 on the Sliders will likewife prevent our be- 
 ing at any Lofs what Glafs to apply to each. 
 Small living objects, fuch as Lice, Fleas, 
 Gnats, fmall Bugs, minute Spiders, Mites, 
 &c. may be placed between thefe Talcs, 
 without killing or hurting them, if care be 
 taken not to prefs down the brafs Rings 
 that keep in the Talcs : and will remain a- 
 live even Weeks in this Manner. But if 
 they are larger than to be treated thus, either 
 put them in a Slider with concave GlafTes, 
 intended for that ufe, and defcribed pag. 10. 
 or in the Cell pag. 19. or elfe examine them 
 
 * In placing your Objects in Sliders, a convex Glafs of 
 about an Inch Focus, to hold in the Hand, and thereby 
 .adjull them properly between the Talcs, before you fefteh 
 them down with the B.afs Rings will be found very con- 
 venient. 
 
 fluck 
 
58 Of preparing and applying Objects. 
 
 ftuck on the Pin, or held between the Ply- 
 ers; either of which Ways they may be 
 view'd at Dleafure. 
 
 If Fluids come under Examination, to 
 difcover the Animalcules that may be in them, 
 take up a fmall Drop with your Pen or Hair- 
 pencil, and place it on a iingle Ifinglafs, 
 (which you fhould have in a Slider ready) 
 or elfe in one of the little concave GlalTes, 
 and fo apply it. But in cafe, upon viewing 
 it, you find, as often happens, the Animal- 
 cules fwarming together, and lb exceedingly 
 numerous, that running continually over one 
 another, their Kinds and real Form cannot be 
 known ; fome part of the Drop muft be 
 taken off the Glafs, and then a little fair 
 Water put to the reft, will make them fe- 
 parate, and ihew them diilinct and well. 
 And this Mixture of Water is particularly 
 requifite in viewing the Semen Mafcnlinwn 
 of all Creatures : for the Animalcules therein 
 contained are fo unconceiveably minute, and 
 yet crowded together in fuch infinite Num- 
 bers, that unlefs it be diluted a great deal, 
 they cannot be fufficiently feparated to di- 
 ftinguifh their true Shape. 
 
 But, if we view a Fluid, to find what 
 Salts it may have in it, a Method quite con- 
 trary to the foregoing muft be employed : 
 for, then, the Fluid muft be fuffer'd to e- 
 vaporate, that the Salts being left behind up- 
 on the Glafs, may more eafily be examined. 
 
 Another, 
 

 Of preparing and applying Objects. 59 
 
 Another, and indeed the moil curious 
 Way of examining Fluids, is, by applying 
 them to the Microfcope, in exceedingly 
 fmall capillary Tubes made of the thinned 
 Glafs poiiible. This was Mr. L e e u w e n - 
 hoek's Method for difcovering the Shapes 
 of Salts floating in Vinegar, Wine, and fe- 
 veral other Liquors ; and fuch Tubes (hou'd 
 be always ready to ufe as occaMon requires. 
 
 For the Circulation of the Blood, Frogs, 
 Newts, or Fifhes are commonly made ufe 
 of; and there are Glafs Tubes in the fingle 
 Microfcope, and a FinVpan as well as Tubes 
 in the double one, on purpofe to confine 
 thefe Creatures, and bring the proper Parts 
 of them to view : which, in Newts and 
 Fidics, are the Tails, and in Frogs the tine 
 filmy Membrane between the Toes of the 
 hinder Legs. Though, if we can contrive 
 to fallen down the Creature, and bring our 
 Object to the Magnifier, the Circulation can- 
 not poffibly be (ten fo plainly any where, as 
 in the Mefentery, or thin transparent Mem- 
 brane that joins the Guts together ; and this 
 Part, by pulling out the Gut a little, may 
 eafily be adjutled to the Magnifier. 
 
 To diffect minute Infects, as Fleas, Lice, 
 Gnats, Mites, &c. and view their internal 
 Structure, requires a great deal of Patience 
 and Dexterity : yet even this may be done, 
 in a very iatisfactory Manner, by means of 
 a fine Lancet and Needle, if they are placed 
 
 in 
 
6o Of preparing and afphing Objects. 
 
 in a Drop of Water : for their Parts will 
 then be feparated with Eafe, and lie fair be- 
 fore the Microfcope, fo that the Stomach 
 and other Bowels may plainly be diftinguifli- 
 ed and examined. 
 
 We fhould always have ready for this 
 Purpofe little Slips of Glafs about the Big- 
 nefs of a Slider, to place Objects on, oc- 
 cafionally j fome of which Slips fhou'd be 
 made of green, blew, and other different co- 
 lour'd Glafs ; many Objects being much 
 more diftinguifriable when placed on one 
 Colour than on another. We fhould like- 
 wife be provided with Glafs-Tubes, of all 
 Sizes, from the fined Capillaries that can be 
 blown, to a Bore of half an Inch Diameter. 
 
 I believe there is no better Way of pre- 
 fcrving tranfparent Objects iri general, than 
 by placing them between clear Ifinglafs in 
 Sliders: But opake Bodies, fuch as Seeds, 
 Sands, Woods, &c. require different Ma- 
 nagement -, and a Collection of them mould 
 be pre ared in the following Manner. 
 
 Cut Cards into fmall Slips, about half an 
 Inch in Length, and the Tenth of an Inch 
 broad : wet them half their Length with a 
 itrong but very tranfparent Gum-water, and 
 with that flick on your Object. As the Spots 
 of Cards are red and black, by making your 
 Slips of fuch Spots you will obtain a Contran: 
 to Objects ofalmoft any Colour: and by 
 fixing black Things on the white, white on 
 
 the 
 
J><UJ. fii 
 
 n 
 
 
 
 [1 
 
 
 j 
 
 
 1 
 
 
 1 ! 
 
 • 
 
 
 ' 
 
 
 r 
 
 i 
 
 i ' i 
 
 ] 
 
 1 
 
 
 
 
 
 
 1 
 
 1 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 1 j 
 
 ii 
 
 ^^*^*^ !!S **"'™™^ ! ^ 2 Z2^&Z^^^^ 
 
Of preparing and applying Objects. 6 r 
 
 the black, blew or green on the red or white, 
 and nil other coloured Objects on Slips mod 
 contrary to themfelves, they will be fliewn 
 to the beft Advantage. Thele Si ids are in- 
 tended chiefly for the new- invented Micro- 
 scope for opake Objects, to be applied between 
 the Nippers : but they will be alio proper 
 for any other Microfcope that can (hew opake 
 Bodies. A little iquare Box flioulJ be con- 
 trived to keep thele Slips in, with a Num- 
 ber of very lliallow Holes jutt big enough 
 to hold them. If fuch Holes were cut 
 through Pieces of that Pattboard Covers of 
 Books are made of, exactly fitted to the Box, 
 and a Paper was patted on one Side of each 
 to fervc for a Bottom to it, three or four 
 fuch Pattboards ftorcd with Objects might 
 lye upon one another in the fame Box, and 
 contain an hundred or more of Slips with Ob- 
 jects fattened on them, always ready for Ex- 
 amination. It will not be found amifs to 
 provide fome Slips larger than others, for 
 the Reception of different fized Objects : 
 But the Pattern hereto annexed (Plate VI.) 
 will better explain my Meaning *. The Box 
 fhould likewise be furniihed with a Pair of 
 Plyers, to take up and adjuft the Slip.-. 
 
 * Mr.. Cuff, in fleilflrett, has ilrc^dy nv' 
 Boxes after this Pattern, which pru've ver convenient 
 Jikewife makes and fells a 11 the AH ■ hir\ :: ; i 
 
 ratus mentioned in t V > i - 'i - 
 
 CHAP 
 
[ 62] 
 
 CHAP. XV. 
 Cautions in viewing Objecls. 
 
 Tl Eware of determining and declaring your 
 ■*-* Opinion fuddenly on any Object ; for 
 Imagination often gets the Start of Judg- 
 ment, and makes People believe they fee 
 Things, which better Obfervations will con- 
 vince them could not pofllbly befeen : there- 
 fore affert nothing till after repeated Experi- 
 ments and Examinations in all Lights and in 
 all Portions. 
 
 When you employ the Microfcopc, (hake 
 off all Prejudice, nor harbour any favourite 
 Opinions j for, if you do, 'tis not unlikely 
 Fancv will betray you into Error, and make 
 you think you lee what you would wifh to 
 fee. 
 
 Remember that Truth alone is the Mat- 
 ter you are in fearch after ; and if you have 
 been miftaken, let not Vanity ieduce you to 
 perliit in your Miftake. 
 
 Pafs no Judgment upon Things over-ex- 
 tended by Force, or contracted by Drynefs, 
 or in any Manner out of their natural State, 
 without making fuitable Allowances. 
 
 There is no Advantage in examining any 
 Object with a greater Magnifier, than what 
 fhews the fame diftinclly ; and therefore, if 
 you can fee it well with the third or fourth 
 
 Glafs, 
 
Cautions in viewing Objects. 63 
 
 Glafs, never ufe tl:e firft or fecond; for the 
 lefs a Glafs magnifies, the better Ligiit you'll 
 have, the eailer yon can manage the Object, 
 and the clearer it will appear. 
 
 It is much to be doubted, whether the 
 true Colours of Objects are to be judged of, 
 when feen through the greatefr. Magnifier? : 
 for as the Pores or Interilices of an Object 
 mud be enlarged according to the magnify- 
 ing Power of the Glafs made ufe of, and the 
 component Particles of Matter muft by the 
 fame means appear feparated many Thou- 
 lands of times farther afunder than they do 
 to the naked Eye, their Reflections of the 
 Rays of Light will probably be different, and 
 exhibit different Colours. And, indeed, the 
 Variety of Colouring fome Objects appear 
 dreft in, may ferve as a Proof of this. 
 
 The Motions of living Creatures them- 
 fclves, or of the Fluids contained within 
 them, as feen through the Microfcope, are 
 likewife not to be determined without due 
 Conlideration : for as the moving Body and 
 the Space wherein it moves are magnified, the 
 Motion mult probably be fo too. And there- 
 fore, that Rapidity, wherewith the Blood 
 feems to pafs along through the VefTels of 
 fmall Animals, muft be judged of according- 
 ly. Suppofe, for Inftance, a Horfe and a 
 Moule move their Limbs exactly at the fame 
 Moment of Time : if the Horfe runs a Mile 
 while the Moule runs fifty Yards (tho* the 
 1 Number 
 
64 Cautions in viewing Objects. 
 
 Number of Steps are in both the fame) we 
 mall readily, I believe, allow the Horfe's Mo- 
 tion to be lwiftefl. The Motion of a Mite 
 viewed through a Microfcope, or feen by the 
 naked Eye, is, perhaps, not much lefs dif- 
 ferent. 
 
 6ome People have made falfe Pretences and 
 ridiculous Boafts, of feeing, by their GlaiTes, 
 the Atoms of Epicurus, the fubtile Mat- 
 ter of Des Cartes, the * Effluvia of Bodies, 
 the Emanations from the Stars, and other 
 fuch like Imporlibilities : But let no ingeni- 
 ous and honeft Obferver give Credit to thefe 
 romantic Stories, or mifpend his Time, and 
 bewilder his Brains, in following fuch idle 
 Imaginations, when there lyes before him an 
 Infinity of real Objects, that may be examin'd 
 with Eafe, Profit, and Delight. 
 
 * Dr. Hichmore pretends, that the Effluvia of the 
 Loadftone have been feen by GlafTes, iffuing from it in the 
 Form of a Mift : And all the reft of the above Extravagan- 
 ces have been boaftcd of by other?. Fid. Leeuwen. Arc. 
 Nat. Tom. ii. P. ii. pag. 54b'. 
 
 
 . 
 
 Me 
 

 
 7j&£ Microscope /##;/<? Eafy: 
 
 OR, AN 
 
 ACCOUNT 
 
 Of what furprizing 
 
 DISCOVERIES 
 
 Have been already Made by the 
 
 MICROSCOPE; 
 
 WITH 
 Ufeful Reflections on them. 
 
 TOGETHER WITH 
 
 A great Variety of new Experiments 
 and Observations, pointing out many 
 uncommon Subjects to the Enquiry of the 
 Curious. 
 
 PART II. 
 
[6 7 ] 
 
 THE 
 
 MICROSCOPE 
 Made Eafy, &c. 
 
 PART IT. 
 
 AVING defcribed the moft ufe- 
 ful Kinds of Microscopes 
 made amongft us j (hewn how to 
 calculate the magnifying Powers 
 of Glasses, and the real Size of Objf. cts; 
 taught the Ways of preparing, examining, 
 and preferring Ob J e c t s -, and given proper 
 Cautions in our judging of what we view; 
 I come now to the Second Part of my 
 Defign, which is, to (hew what Jurprizing 
 Difcoveries have been already made by the 
 Microscope, with ufeful Reflections on 
 them : and alfo to fet forth a great Variety 
 of new Experiments and Observations, point- 
 ing out many uncommon Subjects for the Ex- 
 amination of the Curious. 
 
 F 2 CHAP. 
 
[ 68 ] 
 
 CHAP. I. 
 
 Of the Animalcules in Fluids, 
 
 r T n HE fmalleft living Creatures yet known 
 JL are the Animalcules in Fluids : where- 
 of many Kinds have been difcovered by the 
 Microfcope, of fuch an exceeding Minute- 
 nefs, that a Million of them would not e- 
 qual the Bignels of a large Grain of Sand ; 
 and, it is probable, there may be numberlefs 
 Species of a Size much lefs than thefe. It is 
 alfo likely, that there are as many, or even 
 more Kinds of thefe Invifibles (if I may ufe 
 the Term) than of thofe whofe Size is difcern- 
 able by the naked Eye. Here, therefore, is 
 abundance of Scope for Enquiry and Admi- 
 ration, fince every Drop of Water, or other 
 Liquor, (excepting Oils and Spirits ) either 
 does already, or, upon ftanding expofed a 
 few Days, will be full of living Creatures, 
 of various Sizes and Forms. Some kinds of 
 thefe Animalcules feem to be really Fifh, and 
 are natural Inhabitants of the Water all 
 their Lives : others live there but occafion- 
 ally, in the manner of Gnats, which, from 
 Eggs dropped by their Parents in the Water, 
 become fwimming Animals ; but, after a 
 while, fried their Skins, appear in a Form 
 that bears noRefemblance to what they wore 
 
 before, 
 
Of the Animalcules in Fluids. 69 
 
 before, take Wing, and turn Creatures of 
 the Air. 
 
 We may thus account how Water where- 
 in Pepper \ Hay, Oats, Wheat , or other vege* 
 table Subjlartces are infufed, will foon be- 
 come full of Life : for thefe minute and in- 
 vi/ible little Flies, which are every where 
 hovering in the Air, and ieeking Places to 
 depofit their Eggs, when a Fluid offers well 
 flored with proper Nourishment for their 
 future Offspring, may be fuppofed to refort 
 to it in Swarms, and lay their Eggs there. 
 Thefe Eggs being foon hatch'd, the Infant 
 Brood fwim about and live happily in the 
 Fluid ; till grown to their ftated Size, they, 
 in due Time, change their Forms, employ 
 their Wings, and fly away. 
 
 The Truth of this I have often experien- 
 ced : for after obferving fome kinds of Ani- 
 malcules in feveral Fluids to be grown to a 
 certain Bignefs, on a fudden I have found 
 them all gone away, and only a much fmal- 
 ler, and confequently a younger Race of the 
 fame Kinds remaining ; which alfo, when 
 grown to a like Size have foon after in the 
 fame Manner been gone too. Befides, if 
 the Infufion be covered, tho' with a Muf- 
 lin or fine Lawn, I have conftantly found 
 that few Animalcules will be produced there- 
 in ; but upon taking off the Cover, in a few 
 Days it will be full of Life j which feems to 
 prove, that the Eggs whence thefe AnimaU 
 F i cules 
 
jo Of the x^nimalcules in Fluids. 
 
 cules come, muft either be depofitcd by their 
 own Parents, as I above iuppofe, or be 
 brought along with the Air. And, indeed, 
 both theie Ways may poiiibly be : for 
 as the E'js;s of fuch minute Creatures are 
 lighter than Air, Millions of them may con- 
 tinually float therein, and, being wafted 
 every where indifferently, may perifh in 
 places unfuitable to their Nature, but hatch 
 and thrive when they happen to be lodged 
 in a proper Nidus for them. Some People 
 imagine, that the Eggs of thefe little Crea- 
 tures are lodged in the Pepper, Hay, or what- 
 ever elfe is put into the Water : but were it 
 fo, I cannot think a thin Covering of Lawn, 
 which does not exclude the finer Part of the 
 Air, would prevent their being hatch'dj and 
 therefore muft conclude it a Miftake. 
 
 Tho' W T ater that ftands at reft, and ex- 
 pofed in the open Air, will, after a few Days, 
 have fome Animalcules in it, they will be 
 found in no degree fo numerous as when 
 .vegetable Bodies have been fteeped therein : 
 for no Creatures feem able to lublift on meer 
 Water only, and what little Particles befides 
 may accidentally happen in it can maintain 
 no great Number : But, v/hen, by Infufion 
 of the abovementioned Subftances, Water 
 is ftored with their proper Food, the Micro- 
 fcope can fhew iMyriads of living Creatures 
 in every little Drop. 
 
 As 
 
Pepper Water. y\ 
 
 As every curious Perfon will be defirous 
 to view thefe Wonders with his own Eyes, 
 and communicate them to his Friends, the 
 following Directions for making Pepper- 
 Water, &c. to be kept always ready for Ob- 
 fervation, may not perhaps be unacceptable. 
 
 CHAP. II. 
 
 To make Pepper-Water, and of the 
 Animalcules found therein. 
 
 PU T common black Pepper, grofsly 
 bruifed, into any open VerTel, to cover 
 the bottom of it about half an Inch in 
 Thicknefs, and pour thereon Rain or River- 
 water, till it riles above the Pepper an Inch 
 or thereabouts. Shake or ftir the Water and 
 Pepper very well together when firft you 
 mix them, but afterwards not at all. Ex- 
 pofe your VelTel to the Air uncovcr'd, and 
 in a few Days you'll perceive a little Pellicle 
 or Skin upon the Surface of the Water, re- 
 flecting Prima Colours. This Skin, exa- 
 min'd by the Microfcope, will be found to 
 contain Millions of Animalcules, fcarce dif- 
 cernable at nrft, even by the greateit Mag- 
 nifier, but continually growing bigger till 
 they come to their full Size. Their Num- 
 bers too will every Day increafe exceedingly, 
 F 4 till 
 
j2 Pepper-Water, 
 
 till at length the whole Fluid feems almoft 
 alive : tho' in reality, they lye chiefly on the 
 Surface of the Water, and go not deep 
 therein, unlefs frighted or difturb'd ; but 
 when that happens, they'll fometimes dart 
 down all at once, and not appear again for- 
 fome time. In warm Weather this Skin 
 rifes on the Surface fooner, and you'll per- 
 ceive them grow fafter than in cold : tho', 
 even in the midft of Winter, if the Water 
 be not frozen, the Experiment will fuc- 
 ceed. 
 
 About the Quantity of a Pin's Head of 
 this Scum, taken up with the Nib of anew 
 Pen, or a fmall Hair Pencil, and applied on 
 a (ingle Ifinglafs, firft to the third Magnifier, 
 then to the fecond, and then to the firft, 
 will fhew feveral Sorts of Animalcules leffer 
 each than other, and differing a great deal 
 in Shape as well as Size. 
 
 The Sorts that have been obferved in 
 Pepper-Water, are, 
 
 Firji, The largeft Sort of all, (reprefented 
 Plate VII. Fig. I.) * The Length of thefe is 
 about the Diameter of a Hair, and three or 
 four times more than their Breadth. Their 
 Bodies are very thin and tranfparent, but 
 that fide which feems the Back is darker 
 than the other. They turn themfelves in 
 
 PbUofopk.Travf. N'' 284. 
 
 the 
 
zy.y.. 
 
 I>UuW. 
 
 Fc 9 .I77 
 
 
 V vi ■■' v -^ y 
 
 Fy.TF. 
 
 F-77- 
 
 f-77- 
 
 / 
 
 Tu/. TUT. 
 
 / 
 77, JX. J\j7\f< 
 
 Fu/. 27. 
 
 Fif.jur. 
 
 — <^o 
 
 Fy.XI. 
 
 Fu?. JQII. a.. -^V- 7X771. 6. 
 p. 20S. 
 
Pepper-Water. 73 
 
 the Water often, and fhew both Back and 
 Belly, as 1.2. Their Edges are fringed, as 
 it were, with a great Number of exceeding- 
 ly minute Feet, which are chiefly feen about 
 the two Extremities : At one End there are 
 likewife fome Briftles longer than the Feet, 
 refembling a Tail. Their Motion is fwift, 
 and by their Turns, Returns, and fudden 
 Stops, they feem continually to be hunting 
 about for Prey. They can employ their 
 Feet in running as well as fwimming ; for 
 upon putting a Hair amongft them, they'll 
 often creep along it from End to End, bend- 
 ing in feveral odd Poltures. 
 
 Secondly^ A pretty common fort, whofe 
 Length is about one Third of a Hair's 
 Breadth, with Tails five or iix times as long, 
 and fometimes more. Fig. II. 1 . exhibits one 
 of them with the Tail extended. 2. repre- 
 fents another with its Tail in a Screw-like 
 Form, as they appear very frequently. Some- 
 times, when they lye (till, they thruft out 
 and pull back again a fringed or bearded 
 Tongue ; and a Current runs constantly to- 
 wards them, which is caufed probably by 
 the nimble Motion of fome minute Fins or 
 Legs too fine to be difcerned. 
 
 Thirdly, a Sort about the Size of the laft, 
 but without Tails, appearing fometimes in 
 an oval Shape, as Fig. III. 1 . and fometimes 
 a little longer, refembling a Flounder, in the 
 Manner of 2. Their little Feet may be feen 
 
 plainly 
 
j± Pepper-Water. 
 
 plainly when the Water is juft evaporating, 
 for then they move them nimbly. Now 
 and then two of them are ittw conjoyned, 
 as 3. 
 
 Fourthly, Another fort appear like (lender 
 Worms, about fifty times as long as broad, 
 and whole Thicknefs is about the one hun- 
 dredth Part of a Hair. Their Motion is 
 equable and (low, waving their Bodies ge- 
 nerally but little in their Progreflion. They 
 fwim with the fame Facility backwards 
 or forwards, and being every where of 
 the fame Thicknefs, it is difficult to di- 
 ftin^uifh which End the Head is placed at. 
 See Fig. IV. 
 
 A fifth Sort, is fo amazingly fmall, that 
 an Hundred of them in a Row would not 
 equal the Diameter of a Grain of Sand, and, 
 confequently, a Million of them are but 
 equal to a Grain of Sand in bignefs : their 
 Shape is almoft round. 
 
 A fixth Sort , are about the Thicknefs of 
 the foregoing, but almoft twice as long : 
 and, befides thefe, there are doubtlefs other 
 Sorts which have not duely been attended 
 to. 
 
 It is agreeable enough, while thefe little 
 Creatures are before theMicrofcope,to obferve 
 the different Effects feveral kinds of Mix- 
 tures produce among them. For Example, 
 putting to them the fmalleft Drop imagina- 
 ble of Spirit of Vitriol upon the Point of a 
 
 Pin, 
 
Tepper -Water. jr 
 
 Pin, they immediately fpread themfelves, 
 and appear to tumble down dead. DifTolv- 
 ed Salt kills them, but with this Difference, 
 that inftead of becoming flat as in the for- 
 mer Cafe, they (hrink into oval Forms. 
 Tincture of Salt of Tartar throws them in- 
 to convulfive Motions, after which they foon 
 grow faint and languid, and then dye without 
 any change of Shape. Ink kills them as foon 
 as Spirit of Vitriol, but feems to contract: 
 them feveral Ways. Frefh Blood, Urine, and 
 Spittle kill them in a little while. Sugar dif- 
 folved does the fame; but thereby fome dye 
 flat and others round*. 
 
 If the Water be permitted to dry away 
 without any Mixture, fome Sorts of the Ani- 
 malcules will burfl, but others not : and if 
 a frefh. Drop of Water be put to them, 
 in a 'little while many of them will revive 
 and fwim about again. 
 
 Philofoph. Tranfaft. N°. 203. 
 
 CHAP, 
 
( 76 ) 
 
 CHAP. III. 
 
 Of Hay -Water, 6cc. 
 
 HA Y, Straw, Grafs, Oats, Wheat, Bar- 
 ley, or any other vegetable Production, 
 being infufed in Water, in the Manner ad- 
 vifed before, after fome Days a fort of 
 whitifh Scum or Motherinefs will appear 
 upon the Surface, which, examined by a 
 Microfcope, will be found to contain inex- 
 premble Numbers of minute living Crea- 
 tures of various Sizes, Forms, and Kinds. 
 
 And of thefe fome are the fame exactly 
 as were juft now defcribed in Pepper-Water: 
 for it is to be obferved, that certain Kinds 
 of thefe Animalcules are met with, univer- 
 fally, in all Waters that have flood any con- 
 liderable Time expo fed to the open Air. 
 The mofl general among them is an oval 
 fort of Animalcule, fomewhat in the Shape 
 of an Emmet's Egg (See Fig. V. Plate VII.) 
 They are extreamly nimble, and in a conti- 
 nual fwift Motion backwards and forwards : 
 but fometimes they ftop on a fudden, and 
 turn round on their own Axis numberlefs 
 times with furprizing Velocity, firft one way, 
 and afterwards the contrary *. This Gyra- 
 
 * The Solar Microfcope has difcover'd, that this ftrange 
 Motion is produced by the Aftion of a great Number of 
 Legs or Fins, placed in a circular Order. 
 
 2 tion, 
 
Hay-Water, Sec. 77 
 
 tion, or twirling round as it were on a Point, 
 J have taken notice of in other Kinds alfo of 
 the Animalcules found in Fluids. 
 
 Another pretty common Sort, and in 
 Shape fomewhat refembling the foregoing, 
 js fhewn (Fig. VI.) Their Motion is very 
 fwift, and always with the (harp End fore- 
 mod, whence one may reafonably fuppofe 
 it to be the Head. Some of them are clear 
 from End to End, but curioufly ribbed in 
 the Manner of a Melon : Others are tranf^ 
 parent at their fmall Extremity only, but 
 have their Bottle-End opake. No Legs or 
 Fins can be difcerned in either. 
 
 We find another fort, as long almoft as 
 the largeft in Pepper-Water ', which are very 
 brifk and active, and have a Power of con- 
 tracting or extending themfelves as they 
 fwim along. At the End that feems to be 
 the Fore-part, feveral Feet are vifible j but 
 efpecially when the Water is almoft evapo- 
 rated : for then they fhrink into a Globular 
 Form, and their Feet {landing out may be 
 perceived to move very nimbly. Fig. VII. 
 1 . reprefents one of thefe Animalcules at its 
 full Length ; 2. fhews another of them when 
 contracted. 
 
 There's likewife a Species of Animalcules 
 whofe Bodies are Spherical, but pointed 
 fomewhat like a Pear, and refembling Blad- 
 ders fill'd with Water, wherein a vafl Num- 
 ber of dark Particles fecm in a continual 
 
 Agita- 
 
j 8 Hay-Water, &c. 
 
 Agitation. Their Motion is chiefly a revolv- 
 ing one, turning round perhaps ahove an 
 hundred times in a Minute, firft one way, 
 and then the contrary : and all this without 
 moving a Hair's Breadth out of their Place. 
 But fometimes they move forward very 
 brifkly, turn, return, and fetch a large Com- 
 pafs with feveral Deviations : keeping how- 
 ever, throughout their whole Progrefiion, 
 their pointed End always foremoft. See 
 Fig. VIII. 
 
 I once difcovered in the Scum on the Sur- 
 face of Hay -Water a kind of minute Ser- 
 pents ; for fo I call them from their Motion, 
 which was like that of a Serpent, and from 
 their coiling up themfelves in the manner 
 Serpents do. I kept this Water fome Weeks, 
 and fhewed them to leveral of my Friends, 
 but fince that time have never met with 
 them in any Infufion of the fame fort, or in 
 any other Fluid. Their manner of moving 
 forward, and alfo of coiling themfelves up, 
 is fhewn Fig. IX. 1.2. They were larger 
 than any of the Eel-kinds of Animalcules,, 
 their Motion very different, and not near fo 
 quick. The End that feemed to be the 
 Head was thicker and fomewhat more 
 opake than the other. 
 
 Animalcules in the Shape of Eels are fre- 
 quently met with in many of the Infufions 
 I am now mentioning, and likewife in fe- 
 veral other Liquors. The Bignefs of them 
 1 is 
 
Hay-Water, See. 79 
 
 is very different, fome being an hundred 
 times larger than others, and probably they 
 may differ alio very much in Kind. They 
 have in general a nimble wriggling Motion, 
 but fome Sorts of them are more aclive and 
 vigorous than others. 
 
 Vinegar after ftanding a few Days imco- 
 ver'd, and efpecially in the SummerSeafon, 
 will frequently abound with a kind of theie 
 Eels y large enough to be difcerned by the 
 naked Eye : which has encouraged fome 
 People erroneoufly to affert, that the Sharp- 
 nefs of Vinegar is owing to nothing elfe but 
 the ftriking of thefe Creatures upon the 
 Tongue and Palate with their acute Tails : 
 Whereas it is very certain, that many times 
 none of them can be difcovered even in the 
 foureft Vinegar ; and befides, MlLeeuwen- 
 hoeck has demonitrated, that its Sharpnefs 
 preceeds only from the pointed and penetra- 
 ing Figure of the Salts floating in it, as I 
 (hall find occafion to obferve more fully by 
 and by. 
 
 The Shape of thefe Eel-like Animalcules 
 is delineated Fig. X. 
 
 Dr. Power tells us, * That if Vinegar 
 wherein Eels abound, be but moderately 
 heated at the Fire, they will all be killed, 
 and fink down to the Bottom j but that Cold 
 does them no Injury. For after fuch Vine- 
 
 * Power's Micro/. Obferv. pag. 35. 
 
 gar 
 
80 Hay-Water, &c. 
 
 gar had been expofed a whole Night to the 
 fevereft Froft, and was frozen, and thawed, 
 and frozen again, and fo feveral times over, 
 they were as brifk as ever. He likewife in- 
 forms- us, that, in cold Weather, he put 
 fome Vinegar full of thefe Eels into a Glafs, 
 and poured thereon about the fame Quantity 
 of Oyl, which floating on the Vinegar, all the 
 Eels would conftantly creep up into the Oyl 
 when the Vinegar began to freeze ; but, 
 upon thawing the Vinegar, they as conftant- 
 ly return 'd to it again. Thefe are pretty 
 and curious Experiments. 
 
 A Drop of Oyl of Vitriol mixed with the 
 Vinegar kills them in the fame manner as 
 Fire does. 
 
 If fome Grains of Sand be put among the 
 Eels before the Microfcope, it will be high- 
 ly entertaining to fee them ftruggling and 
 ernbarrafTed, as it were, amongft large 
 Stones. 
 
 CHAP. 
 
[Si ] 
 
 CHAP. IV. 
 (y Eels in Past e. 
 
 WHoever is defirous to be furnifh'd 
 with minute Eels always ready for the 
 Microfcope, needs only boil together a little 
 Flour and Water, and make fuch Parte there- 
 of as Bookbinders commonly uib; or it may 
 be bought of them. It fhould neither be 
 very rtifi; nor very watery, but of a mode- 
 rate Confidence. Expofe it to the Air in an 
 open Veflelj and prevent its hardening or 
 becoming mouldy on the Surface, by beat- 
 ing it well together when you find any 
 Tendency that way ; for if it grows hard or 
 mouldy, your Expectation will be difap- 
 pointcd. After fome Days it will turn four, 
 and then if examined attentively, you'll dif- 
 cern Multitudes of exceedingly fmall, long, 
 flender, wriggling Animalcules, which grow 
 larger daily, till you'll be able to fee them 
 with the naked Eye. 
 
 To promote their coming forward, pour 
 every now and then a Drop of Vinegar on 
 your Parte : and after they are once produ- 
 ced you may keep them all the Year, by 
 putting to them fometimes a little Vinegar, 
 or Water, if the Parte becomes too dry, and 
 fometimes a little Supply of other four 
 Parte ; taking care continually to prelerve 
 G the 
 
82 Eels in Pa/le. 
 
 the Surface in a right Condition, which will 
 eafily be done when it is well ftock'd with 
 thefe Animalcules : the continual Motion of 
 them preventing any Mouldinefs thereon. 
 
 A Water-Glals, cr fome other Glafs Vef- 
 fel, is the moil convenient to keep your 
 Pafte in ; for by holding it up againft the 
 Light, you'll oftentimes perceive the Eels 
 wriggling thcmfelves above the Surface of 
 the Pafte upon the Sides of the Glafs, and 
 may be able to take feveral of them with a 
 Pen or Hair- Pencil, much more difengaged 
 from the Pafte, and confequently fitter for 
 View, than if you are obliged to examine 
 the Pafte itfelf in order to find them in it. 
 
 Apply them to your Microfcope upon a 
 fingleTalc or Iiinglafs, after having firft put 
 on it a very fmall Spot of Water for them to 
 fwim about in. The thicker your Pafte is, 
 and the more they are invelop'd in it, the 
 greater Proportion of Water will be requifite 
 to dilute it, that they may difentangle them- 
 felves, and be rendcr'd diftinclly vifible. 
 
 They are very entertaining Objects, exa- 
 min'd by any kind of Microicope, but par- 
 ticularly the Solar one, by which I have 
 magnified them fometimes to an Inch and 
 half, or two Inches in Diameter, with a 
 Length proportionable, and have found 'em 
 anfwer exactly the Appearance of fuch fiz'd 
 Eels. The internal Motion of their Bowels 
 may very plainly be diftinguifh'd, and when 
 
 the 
 
Of Rain-Water, 8ic. 2$ 
 
 the Water is dry'd almoft away, and they 
 are near expiring, their Mouths may be feen 
 opening to a confiderable Width. 
 
 CHAP. V. 
 
 Of Rain- Water and other Waters. 
 
 MR . Le e u w e n H o e k fays, that at fir ft 
 he could difcern no living Creatures 
 in Rain- Water ; but after (landing fome 
 Days, he difcover'd innumerable Animalcules 
 many thoufands of times lefs than a Grain 
 of Sand, and in Proportion to a Mite as a 
 Bee is to a Horfe. 
 
 In other Rain-Water, which had likewife 
 flood fome time, he found the fmalleft fort 
 he had ever feen ; and in a few Days more, 
 met with others eight times as big as thefe, 
 and almoft round. 
 
 In another Quantity of Rain-Water, that 
 had been expofed like the former, he difco- 
 ver'd a kind of Animalcules with two little 
 Horns, In continual Motion. The Space be- 
 tween the Horns was flat, tho' the Body was 
 roundiib, but tapering a little towards the 
 End, where a Tail appear'd, four times as 
 long as the Body, and the Thicknefs of a 
 Spider's Web. He obferved feveral Hun- 
 dreds of thefe within the Space a Grain of 
 Sand would occupy. If thev happened on 
 G 2 the 
 
84 Of Rain-Water 
 
 the leaft Filament or Stringency were en-tang.* 
 led in it, and then would extend their Bodies 
 into an oblong Round, and ftruggle hard to 
 difengage their Tails. He obferved a fecond 
 Sort of an Oval Figure, and imagin'd the 
 Head to ftand at the fharpeft End. The 
 Body was flat, with feveral fmall Feet mov- 
 ing exceeding quick, but not difceroable 
 without a great deal of Attention. Some- 
 times they changed their Shape into a per- 
 fect Round, efpecially when the Water be- 
 gan to dry away. He met alfo with a third 
 Sort, twice as long as broad, and eight times 
 fmaller than the tirft : yet in thefe he dif- 
 cerned little Feet, whereby they moved very 
 nimbly. He perceived likewife a fourth 
 Sort, a thoufand times fmaller than a Loufe's 
 Eye, and which exceeded all the reft in 
 Brifknefs : he found thefe turning them- 
 felves round, as it were upon a Point, with 
 the Celerity of a Top. And he fays, there 
 were feveral other Sorts. 
 
 It is common, in Sum-mer-time, for the 
 Water that ftands in Ditches to appear fome- 
 times of a * greenim and fometimes of a 
 reddifli Colour, which upon Examination 
 
 with 
 
 * The Infects that melt commonly difcolour the Waters 
 are of the Shrimp- Kind, called by Swammerdam Pultx 
 aquaticus arborefcens, from the branching out of their little 
 Horns : they are often fo numerous in ftagnating Waters, 
 in May or June, at which time they -copulate, as to make 
 
 them 
 

 and other Waters. 85 
 
 with the Microfcope is found in ti rely owing 
 to infinite Millions of Animalcules crowded 
 together on the Surface of it, and giving it 
 fuch Appearance. Their Bodies are oval, 
 and transparent at both Ends, but the Mid- 
 dle either green or red, according to the Co- 
 lour of the Water they are fwimming in. 
 This middle Part, viewed with the firft or 
 fecond Magnifier, feems coinpofed of Glo- 
 bules, and bears (o near a Refemblance to 
 the Rows or Spawn of Fifties, that 'tis rea- 
 fonable to believe it really may be the fame: 
 and the more fo flill, as they are found after 
 fome time perfectly clear and colourlefs, and 
 therefore may be prefumed to have ihed 
 their Spawn. 
 
 The Water that drains from Dunghills, 
 and looks of a deep brown Colour, is fo 
 thronged with Animalcules, that it fcems to 
 be all alive j and muft be diluted with Water 
 before they can be iufriciently feparated to 
 diftinguifh their various Kinds. Amongft 
 thefe one Sort is found, which I don't re- 
 member to have feen elfe where, and there- 
 fore give a Draught of (Plate VII. Fig. XI.) 
 Their middle Part appears dark, and befet 
 with Hairs, but both Ends of them trail f- 
 
 them appear of a pale or deep Red, and fometimes of a 
 Yellow Co'our, according to the Colour of themfelves. The 
 green Scum fo commonly feen on the top of Handing Wa- 
 ters in Summer-time, is nothing but innumerable green Ani- 
 malcules. Vkk Der ham's Pbjfic. Thiol, pag. 178. 
 
 G 3 parent : 
 
86 Animalcules in Waters. 
 
 parent : their Tails are tapering with a long 
 Sprig at the Extremity, and their Motion is 
 flow and waddling. This Dunghill- Water 
 abounds alfo with a fort of capillary Eels, 
 that are extreamly active. 
 
 An Infufion of any Her/?, Grain, Fruit, 
 or Flower^ made in common Water, will be 
 found after a few Days to contain fome 
 Kinds of Animalcules peculiar to itfelf ; and 
 this, tho' aftoniiiiing, may be accounted for 
 in a very reafonable manner ; for a little Ob- 
 fervaticn will mew, that every Fieri?, Grain, 
 Fruit, or Flower is allotted by Providence to 
 be the Food of fome particular fort of Bird, 
 Bcaft, or In feci of the vifible and larger Kinds; 
 and we may iuppofe it, in like manner, 
 when infufed in Water, to afford alfo a pro- 
 per Nourimment for fome or other of thofe 
 numberlefs Species of minute Creatures, 
 which are iircifible to the naked Eye, and 
 not to be difcovered without a good Micro- 
 fcope. And as to this Particularity of Ani- 
 malcules, I refer the Curious (who have not 
 yet been convinced by Trials of their own) 
 to the Obfervations of Monfieur Job lot, 
 (ProfeJJ'or Royal of the Mathematicks, and 
 of the Royal Academy of Painting and Scul- 
 pture at Paris) on the various Kinds difco- 
 ver'd by him in the fevcral Infufions follow- 
 ing : the Pictures of which Animalcules he 
 has given, as well as a Defcription o[ them. 
 He examined the Infe lions of Pepper, black, 
 i white 
 
Animalcules in Waters. %j 
 
 white and long : of Senna, of Pinks, of 
 Cyanus or Blewbottle, of Ro/es, Jeffamin, 
 Rasberry- Stalks, Tea, Barberries, Fennel, 
 and Sage, Marigold- Flowers, four G 'rapes , 
 and Melon-Rind, and found different Ani- 
 malcules in them all. Hay, new and old, 
 abounded with many Kinds ; Rhubarb, 
 MuJJjrocms, facet Bafil, • Gtron- Flowers, 
 had their particular Animalcules. The Ane- 
 mony afforded ibme very wonderful % ; Ce- 
 lery produced many Kinds : JFheat-Ears and 
 Straw, many Kinds : Straw of Barley, Rye, 
 Oats, and Turki/l: Corn, many Kinds : Oak- 
 Bark, new and old, afforded great Variety. 
 Some of thefe Infufions he kept a whole 
 Year round, and obferved, not only that 
 each Infufion had Animalcules of Shapes 
 quite different from thofe in others ; but, 
 likewife, that in the fame Infufion different 
 Kinds of Animalcules appear'd at different 
 times. 
 
 N. B. It is highly probable, that the Place 
 where Infufions are made, in a City, or in 
 the Country, expofed to the open Air, or 
 fhut up within a Houfe, as alio the Seafon 
 of the Year, and its Temper as to Heat or 
 Cold, may occafion great Differences in the 
 
 * Mr. Joblot's Draught of the Animalcules in this In- 
 fufion reprefents an exaft Satyr's Face upon their Backs : I 
 jecommend the Tryal to the Curious. 
 
 Kinds 
 
88 Animalcules in Waters. 
 
 Kinds of Animalcules to be found in the 
 fame Infufions. 
 
 We fometimes find in our Infufions of 
 vegetable Productions, and in other Waters 
 that have ftood a while uncover'd, an Ani- 
 mal much larger than any before defcribed, ' 
 of a very (insular and furprizing Form, as 
 pictured 'Plate VII. Fig. XII. This little 
 Creature is in its middle State ; it lately was 
 a Worm, and will foon become a Gnat. 
 For X Gnats depofit their Eggs in a kind of 
 flimy Matter on the Surface of the Water, 
 and fatten them to fomething that may pre- 
 vent their being waflied away or feparated 
 too foon. From thefe Eggs proceed a num- 
 ber of minute Worms, which finking to the 
 Bottom of the Water, make for themfelves 
 Cafes or Coverings of fine Sand or Earth ce- 
 mented together with a fort of Glew, but 
 open at both Ends, for them to come out of 
 or retire into, as they find occafion. After 
 a time, quitting thefe Habitations, and the 
 Figure of Worms, they re-afcend to the top 
 of the Water in the Shape now before us, 
 /helled all over, with a large Flead and 
 Mouth, a Couple of black Eyes, two Horns, 
 feveral Tufts of Hairs or Briftles on different 
 Parts of the Body, and a Tail with a Brum 
 of Hair at the End of it, which being 
 
 + Spe&acle de la Nature, Engl ft Edit. i:mo, pag. 123. 
 Hooke's Microg. p. 1 86. 
 
 fmeared 
 
Animalcules in Waters. 89 
 
 fmeared over with an oily Fluid, ferves like 
 a Cork to keep them above Water ; their 
 Heads being fometimes lifted into the Air, 
 and fometimes plunged into the Water, while 
 the Tail Hides along the Surface. And if the 
 Oil on the Tail begins to dry, they fhed 
 from their Mouth a new Supply upon it, 
 which reftores its Ability of fleering where 
 they pleafe, without being wetted or preju- 
 diced by the Water. After living in this 
 manner the Time appointed by Providence, 
 a ftranger Change fucceeds : for refigning 
 their Eyes, Horns, and Tail, and carting oft 
 their whole Skin, there ilTues forth a Race 
 of Infects of a quite different Element : the 
 molt beautiful and delicate Plumage adorn* 
 their Heads ; their Limbs are conftituted 
 with the fineft Texture •> they have Wings 
 curiouily fringed and ornamented ; their 
 whole Bodies are inverted with Scales and 
 Hair, and they are actuated by a furpriz- 
 ing Agility : in lhort, they become Gnats, 
 and lpring into the Air. And, what is moil 
 amazing, a Creature that but a Minute fince 
 was an Inhabitant of the Water, would now 
 be drowned if it were plunged therein. 
 
 I have been the more particular in my 
 Account of this Mctamorphofis, as I appre- 
 hend many forts of the Animalcules in Flu- 
 ids undergo Changes in fomewhat a like 
 manner. I fhall only add here, that the 
 little Creature, whole Picture I have given, 
 I ii 
 
go Animalcules in Waters. 
 
 is a delightful Object for the Micro/cope, its 
 white Heart beating diftinctly, and the Mo- 
 tion of all its Inteftines being perfectly vifi- 
 
 ble and extraordinary. Of the Gnat I (hall 
 
 fpeak farther in its proper Place. 
 
 The Waters every where abound with 
 Life, and are an endlefs Subject of Employ- 
 ment for the Micro/cope : Seas, Rivers, 
 Ponds, Ditches, and almoft every Puddle 
 can by its Affi fiance prefent us with living 
 Wonders never before difcover'd : for fuch 
 Examinations have as yet been but little at- 
 tended to, even by People that have got 
 thefe Inftruments, and alfo a Genius to ufe 
 them. But I am in hopes this Treatife may 
 excite them to be more induftrious, and not 
 fuffer a little Difficulty, or a few Difappoint- 
 ments, to difcourage them from a Study that 
 can fo amply reward their Pains. 
 
 In feveral of * Mr. Leeuwenhoek's 
 Letters to the Royal Society, we meet with 
 an Account of fome furprizing Animalcules 
 found adhering to the Roots of the hens 
 Palujlris^ov Duck-Weed, (which in Summer- 
 time floats plentifully on the Surface of 
 Ponds and Ditches) as examined by him in 
 a Glafs Tube filled with Water. One Sort 
 
 * Vid. PkiL Trwrf. Numb. 2 S3, 29;, 357. 
 
 of 
 
/ ./</.(). 
 
 Flat* nn 
 
 fy.ll./z.fj 
 
 I-y.M./ifi 
 
 ■Fey. 17: n gi 
 
 I-y.K/ifi 
 
 ',i'""'',- 
 
 yy ,ll| i y \ 
 
 ''•in H* 
 
 Tj.TI/i, S 3 
 
 2'ey.m./i,.gQ 
 
 Fur.mr.. 
 
 y-wf-93 
 
Animalcules in Waters. 91 
 
 n{ thefe was fhaped like Bells, with long 
 Tails, whereby they fattened themfeives to 
 the Roots of thefe Weeds ; and fometimes 
 twenty of thefe were feen together, gerltly 
 extending their long Tails and Bodies, and 
 then, in an Inftant, contracting them again. 
 
 See the Draught, Plate VIII. Fig. I. 
 
 A. reprefents a Root of Duck-Weed with 
 the Tails of many Animalcules adhering to it. 
 
 b b b b } &c. ihew their Bell-like Bodies. 
 
 c c c c, their long Tails. 
 
 Another extraordinary Kind of Animalcule 
 (which fee Fig. II.) appears in a Sheath or 
 Cafe, a, b y c, the End whereof it fattens co 
 the Duck- Weed Roots. This little Creative 
 has two feeming Wheels with a great many 
 Teeth or Notches, coming from its Head, and 
 turning round as it were upon an Axis, d t c. 
 At the leatt Touch it draws the Wheel-work 
 into its Body, and its Body into the Sheath, 
 after which it appears as Fig. III. But when 
 all is quiet, it thrutts itfelf out again, ai 
 the Rotation of the Wheel- work is rcne\. 
 Mr. Leeuwenhoek took notice of om 
 thefe, whofe Cafe feem'd compoied of r 
 nute Globules (Fig. IV. a, b.) and in dv 
 difcover'd the Wheel- work to confilt of J 
 roundihh Parts with little Divifions betw< 
 each, tho' only three of thofe roundiih 1 
 could be feen, the fourth lying behin ; 
 reprefented Fig. V. This convinced 1 
 how much he had been mittaken, in beli - 
 
 1; T 
 
g 2 Animalcules in Waters. 
 
 ing them, from their common Appearance, 
 to be two Wheels, whereas the real Form 
 of this Wheel-work is as at Fig. V. 
 
 To find thefe Animalcules, choofe Duck- 
 Weed that has long Roots j for young Plants 
 with fhort Roots feldom afford any. Be 
 careful too that they are not cover'd with a 
 rough Matter, or tending to Decay, as they 
 will often be. Let the Roots fink gently 
 down in a Glafs Tube filled with Water, 
 and fo apply them to the Mi cr of cope. Two 
 or three Animalcules will be found fome- 
 times adhering to one Root ; and at other 
 times you may examine feveral, and not be 
 able to meet with any. 
 
 In the Water or flimy Matter found in 
 Leaden Pipes or Gutters, Mr. Le eu wen- 
 hoe k met with various Kinds of Animal- 
 culeSy and, among the reft, with Multitudes 
 that appear'd to have a fort of Wheel-work 
 turning round fomewhat in the former 
 manner -f . Thefe Creatures, when the Wa- 
 ter dries away, contract their Bodies into a 
 globular or oval Figure and reddifh Colour, 
 and become fixt in the dry Dirt, which 
 grows as hard as Clay : but whenever a 
 piece of fuch Dirt is put in Water, in about 
 half an Hour's Time they open, and by 
 
 + Phil. Traftf. No. 289. Leeuwen. Arc. Nat. Tom. II. 
 Epijl. 149. 
 
 degrees 
 

 Animalcules in Waters. 93 
 
 degrees extend their Bodies, and fvvim about : 
 and this they did after fome of this Gutter- 
 Dirt had been kept dry for twenty one 
 Months together. Whence he concludes, 
 that the Pores of their Skin are clofed fo 
 perfectly, as to prevent all Perfpiration, by 
 which means they are preferved till Rain 
 falls, when they open their Bodies, fwim 
 about, and take in Nourishment. 
 
 Fiii. VI. VII. (hew two of thefe Animal* 
 tules in different Pohtions. 
 
 Fig. VIII. is the Form they appear in 
 when dry and contracted. 
 
 We may find in the Waters of our Ditches 
 feveral Species both of Teftaceous and Cruf- 
 taceous Animalcules : two of the latter fort, 
 which are mod remarkable, are (hewn (Plate 
 IX. Fig. I. and II.) in a fwimming Pofture, 
 with their Backs towards the Eye. Their 
 Legs are fomewhat like Shrimps or Lob^ 
 iters, but of a much more curious Structure. 
 They are lefs than a very imall Flea, but 
 are all Breeders, and carry their Spawn either 
 under their Tail, or in two feeming \ Bags 
 hanging from their Sides, as in Fig. II. 
 Thefe Bags may fometimes be obferved 
 broken, and the Spawn (coniiiling of Glo- 
 bules very large in Proportion to the Crea- 
 
 \A>can. AW. Tom. II. Epift. 121. Pbilc/oph. TranfaSi. 
 Numb. 7 88. 
 
 ture) 
 
94 Animalcules in Waters. 
 
 ture) fcatter'd about the Water. There is 
 alio a third Sort, as beautiful as the fore- 
 going, but not near fo large ; its Shape more 
 refembfes a Shrimp, and it carries its Spawn 
 as the Shrimp does. Thefe three Species of 
 Animalcules appear to have only one Eye, 
 and that placed in the middle of the Fore- 
 i, without fo much as the leaft Trace of 
 even n dividing Line. They are often to be 
 tnd fo tranfparent, that the Motion of 
 eii Bowels is ictn diftinctly by the Micro- 
 be, together with a regular Pulfation in a 
 le Part, which therefore we may fuppofe 
 to be the Heart. 
 
 I fhall finifh this Head, with defcribing 
 a very wonderful Kind of minute Animal \ 
 tlie extraordinary Form whereof (about 
 thrice the Bignefs it appeared to the naked 
 Eye) whilft in the Water and fattened to 
 the Root of a Weed, is given Fig. III. This 
 was a large one of the Sort, and had eight 
 Horns ; whereas the fmaller ones have fel- 
 dom more than fix. It is likewife fhewn 
 here as extended to its full Length, but 
 when contracted is not a fourth Part fo long. 
 It fixes by the Tail to the Roots or Stalks of 
 Water- Plants. On the upper Side a very 
 fmall Animalcule (a) is reprefented coming 
 out of the other's Body. This was fuppol- 
 ed at firil to have fattened itfelf there by 
 fome Accident 3 but by obferving it nar- 
 row lv, 
 
Ity.j3' 
 
 TL^JX. 
 
 Fuf.ir.f.yi, 
 
 I&K; 
 

 
Animalcules in Water. 95 
 
 rowly, it was difcovcr'd to be a young one 
 in the Birth : for though it had but four 
 very irnall Horns when rirft feen, after fix- 
 teen Hours its Horns and Body were grown 
 much larger j and in four Hours more it 
 was quite excluded its Mother's Body. 
 Again ft this, on the under fide, appeared a 
 little round Knob which gradually increafed 
 in Bigneis, and in a few Hours became 
 pointed as at (b). Thirteen or fourteen 
 Hours after, it was grown much larger, and 
 alfo had two Horns. In twenty-four Hours 
 four Horns were (cen upon it, one whereof 
 was fmall, the fecond larger, and the other 
 two very large, extending and contracting 
 more vigorouily than their Fellows. Three 
 Hours afterwards this Animalcule likewife 
 fell off from its Mother, and fhifted for 
 itfelf. 
 
 The above Account is the Subftance of 
 Mr. Leeuwenhoek's Letter to the Royal 
 Society, Phil Tran/l Numb. 283.— And in 
 Numb. 288. we meet with a farther De- 
 fcription of the fame Animalcule by an En- 
 glijh Gentleman, whom Mr. Leeuwen- 
 hoek's Relation had put upon hunting after 
 it. He favs, he difcovered one of them in 
 iome clear Water taken out of a Ditch, but 
 with the utmoft Attention could find no 
 more therein. It appeared the firft Day as 
 in (Fig. IV.) but he tells us, it varied every 
 
 Moment, 
 
9 6 Animalcules in Waters. 
 
 Moment^ and the Knob (a) which looked 
 like the Gut Ca?cum, was fometimes a little 
 longer. Two or three Days after he per- 
 ceived fome white Fibres at the Extremity 
 of the Knob, and on the fourth Day it lay 
 extended at full Length, and appeared as in 
 Fig. V. and he was then convinced, that 
 what he imagin'd an Excrefcence, was in 
 Reality a young Animalcule of the fame 
 Species, ifiuing from the old one, and hav- 
 ing fix Horns. Next Day he found it in the 
 Water entirely feparated, and about a Third 
 of its Parent's Length. The Horns come 
 out like Radii, not from the lixtremity, but 
 quite round a fmall Knob, which pro- 
 bably is the Head : They have a vermicular 
 Motion, and can extend or contract them- 
 felves either fingly or altogether. The other 
 End is flat, and by that it often fattened 
 to the Bottom or Side of the Glafs wherein 
 he kept it. It alfo contracts and dilates its 
 Body, and can bring both Bodv and Horns 
 into a fmall Compafs, as in Fig. VI. and 
 Fig. VII. The Horns are perfectly white, 
 the Body yellowifh, and not eafily difcern- 
 ab!e by the naked Eye ; being, when ex- 
 tended, no thicker than a large Horfe-Hair. 
 
 Monf. Buffon in a Letter to Martin 
 
 Folkes, Efq; now President of the 
 
 Royal Society ', dated at the Garden of Ver- 
 
 failles, iSth July 174 1, fends an Account 
 
 (as 
 
Animalcules in Wafers. 97 
 
 (as a new Difcovery in natural Hiitory) of a 
 Creature called * Polype, found adhering to 
 the Lens Paluflris, which, being cut through 
 the Middle, from the upper Half a Tail 
 proceeds, and from the lower Haifa Head: 
 fo that one Animal becomes two. If it be 
 divided into three, the middle Part moots 
 forth a Head and Tail, the upper Part a 
 Tail, and the lower Part a Head j and all 
 three become as perfect Animals as the firit. 
 Whence he concludes, that in the boundlefs 
 Variety of the Works of Providence, every 
 Thing that can be, is. 
 
 Another Letter to the fame Gentleman, 
 dated at the Ha? ue, Sept. 15. 1 74 1 . from the 
 Honourable — Bentinck, Efqj fays, That 
 a young Man of Geneva, looking for fmall 
 In feds in Water, few fome little Things 
 which he took for Plants, but examining 
 them carefully he perceived fome Motion in 
 them, and found them contract when 
 touch'd. It was a long while, however, be- 
 fore he could determine whether they were 
 Plants or Animals : for he fiw feveral young 
 Shoots coming out upon them, and that as 
 far as four Generations, hanging to one ano- 
 ther. But he has fince found them to eat 
 
 * The Name Pol -pus, or Ma 'Feet, is given to feveral 
 Fifties of the Star-Tijb and Cut . Kind, feme whereof, 
 
 befides feveral Claws, hav-j two long Trunk?, which they 
 can extend to a great Diftanci :<• feize th r Prey : and this 
 Animalcule, I fuppofe, is called Polype from fomewhat of a 
 Jike form. 
 
 H Infects, 
 
oS Animalcules in Waters. 
 
 Infedts, and even raw Meat. They faften 
 themfelves by one Extremity to fome Plant, 
 or the Side of a Glafs, and have at the other 
 End fix or eight Horns, wherewith they 
 hold their Prey. 
 
 Fig. VIII. is taken from a Drawing fent 
 with this Account. 
 
 He cut one of thefe Creatures to fee what 
 would become of it, and fome Days after 
 found new Arms growing out where others 
 had been cut away. Since that, he has di- 
 vided them the long way, the broad way, 
 obliquely, and every way poflible, all with 
 the fame Succefs. He has alfo gone on 
 fubdividing them, and has not found them 
 propagate any other Way than by Shoots, 
 and without Copulation. 
 
 Both thefe Letters feem to mean the fame 
 Animalcule Mr. Leeuwenhoek defcribes, 
 though with farther extraordinary Particulars, 
 which I believe the Curious will judge it 
 worth their while carefully to examine into. 
 
 Upon the Whole, this Animalcule appears 
 to be fome what of the Star-Fifo Kind, or 
 between that and the Sea-Muflroom y or 
 Anemone : which is a little Animal found 
 frequently on the Coafts of Normandy *. 
 They are feen fticking on the Declivity of 
 Rocks ; fome red, fome green, and fome 
 
 * Vid. Speaacle de la Nat. Part II. Dial. 22. 
 
 Of 
 
Animalcules in Waters. 99 
 
 of other Colours : where they look like 
 Mufhrooms while fhut and folded up, but 
 like Anemonies when they open and difpky 
 thcmfelves. There is no opening them by 
 Force without destroying them ; but on 
 Preflure they fomctimes eject feveral young 
 ones of different Sizes, which feems to prove 
 them both Male and Female, and alfo to be 
 viviparous. If you loofen their Hold, carry 
 them away, and keep them in Water, they 
 will fix themfelvcs to the firft convenient 
 Place they find. When the $>ea-Mu(l?room 
 is about to open, it raifes itfelf, and thru lis 
 out two little white and ftriped Bodies like 
 Bladders, round which appears a great Variety 
 of Points or Trunks of different Sizes and 
 Colours ; whence fome Naturalifts have 
 called it the Sea- Anemone. This Opening, 
 not unlike the Blowing of a Flower, has 
 inclined others to look upon it as a fort of 
 Plant, or elie as partaking both of the Ani- 
 mal and Vegetable Nature. But as all thefe 
 little Points or Studs are not Leaves, but a 
 fort of Snouts or Trunk?, through which 
 this Creature fucks in its Nourishment, as 
 the Sea-Urchin and Slar-Fijh do through 
 their fine Reeds or Prickles, we can't denv 
 it a Place in the Rank of Animals ; and 
 efpecially after lb remarkable aCircumftance 
 (confirmed by ocular Teiiimony) as that of 
 three or four young ones ilTuing from the 
 Parent upon fqueezing it. 
 
 H 2 There 
 
i go Animalcules in Waters. 
 
 There is a fort of Star-Fifl\ called by 
 Rondeletius pag. i2i. Stella Arbor efc ens y 
 which from a Body fomewhat like the Sea- 
 Urchin, fends out five Branches in Form of 
 a Star : thefe five divide into ten, thofe ten 
 again into twenty ; the twenty into forty, 
 the forty into eighty, the eighty into one 
 hundred and fixty : the one hundred and 
 fixty into three hundred twenty j the three 
 hundred twenty into fix hundred forty ; the 
 fix hundred forty into one thoufand two 
 hundred eighty 3 the one thoufand two hun- 
 dred eighty into two thoufand five hun- 
 dred fixty y the two thoufand five hundred 
 fixty into five thoufand one hundred twenty ; 
 the five thoufand one hundred twenty into 
 ten thoufand two hundred forty ; the ten 
 thoufand two hundred forty into twenty 
 thoufand four hundred eighty , the twenty 
 thoufand four hundred eighty into forty 
 thoufand nine hundred fixty ; and thofe 
 again into eighty one thoufand nine hundred 
 
 twenty. The farther Divifions could not 
 
 certainly be traced ; tho' probably, when 
 the Fifh was alive, they might have been 
 diftinguim'd much beyond this Number -j-. 
 All thefe flender Threads, thro' their whole 
 Length, have minute Clafpers iffuing from 
 them, and appear very amazing when exa- 
 min'd by the Micro/cope. 
 
 t Fid. Philofoph. Tranfaft. N°. 57. 
 
 To 
 
Animalcules in Waters. 101 
 
 To conclude this Chapter. If the fmall- 
 
 eft living Creatures that have heen yet dif- 
 cover'd are produced in the Waters, in them 
 we find alio the largeft and moft monftrous. 
 No Bird or Bead comes near the Size ofmany 
 Kinds of Fillies, nor can the Elephant itfelf 
 be brought in Comparifon with the Whale. 
 
 Joannes Faber Lynceus allures us, 
 that in the Year 1624 he faw himfelf a 
 Whale, that was caft upon the Shore ncaL- 
 Silnta Severa, about thirty Miles from Rome, 
 ninety one Palms in Length, and fifty in 
 Thicknefs : its Mouth was fixteen Palms 
 long and ten high, and being opened and 
 kept gaping, a Man on Horieback might 
 therein find Room enough. Its Tongue was 
 twenty Palms, that is, about fifteen Foot in 
 Length. He adds, that four Years before, ano- 
 ther Whale was caft near the Ifland oWor/ica, 
 not fir from the Coaft of Italy s which, be- 
 ing a Female, was found big with a Cub 
 thirty Foot long, and fifteen hundred Pounds 
 in Weight. He fays, the Carnea Pinguedo 
 [Lard or Fat] only of the Parent Whale, 
 weighed one hundred and thirty five thou- 
 fand Pounds. 
 
 Let us now refled: how amazing the Dis- 
 parity between fuch a Fifh as this, and a 
 minute Animalcule lefs than the thousandth 
 Part of a Grain of Sand in Bignefs ! How 
 innumerable mud the Kinds of Creatures be, 
 
 H 3 that 
 
102 An Examination of 
 
 that form the Progreflions from one Size to 
 the other ! And how equally wonderful does 
 the Hand of Providence appear, whether it 
 actuates an enormous Mountain of Matter, 
 or enlivens an Atom ! 
 
 CHAP. VI. 
 
 An Examination of the Blood in Animals. 
 
 WE cannot employ the Microfcope to 
 any more uie-ful Purpofe, than to 
 view the natural Courfe of the Blood within 
 its VefTels, or examine 'the Contexture of it 
 when extracted from them : for the Prefer- 
 vation or Reftoration of the Health of Man 
 may be greatly advantaged by fuch Enqui- 
 ries. 
 
 By feeing it within the VefTels, we may 
 judge of the Situation, Dimenfions, Arrange- 
 ment, and Ramifications of the Arteries and 
 Veins through which it paries, together with 
 the general State of the Fluid, the Degree 
 of its Impulfe, Progreffion, or Motion, and 
 the Tendency or Direction of its Current 
 pafTing through them. 
 
 When taken from the VefTels, we can 
 
 examine it more minutely, and obferve all 
 
 the little Alterations that may happen in the 
 
 Mixture, Size, Form, and Quality of the 
 
 2 Particles 
 
the Blood of Animals. 1 03 
 
 Particles compofing its more folid or more 
 fluid Parts. 
 
 I mall now (hew how the Microfcope may 
 be employed in both thefe Ways 3 but think 
 proper topremife a fliort Account of the Blood 
 itfelf, fince our Knowledge of that will the 
 better enable us to make a right Judgment 
 when we come to fee it circulate. 
 
 CHAP. VII. 
 
 Some Account of the Blood, as examined 
 by the Microscope. 
 
 HUman Blood, and the Blood of Land- 
 Animals, is found by the Microfcope 
 to confifl of round red Globules floating in 
 a tranf parent Water or Serum. Each red 
 Globule is made up of fix fmaller and more 
 tranfparent ones : and Mr. Leeuwenhoek 
 has diicover'd,that each of thefe again is com- 
 pofed of fix Globules ftill more minute and 
 colourlefs : fo that every common red Glo- 
 bule is compounded of at lead; thirty-fix 
 fmaller ones ; and perhaps the Divilion may 
 itill go on much farther *. 
 
 * Vid. Leeuwen. Arc. Nat. Tom. IV. pag. 12. 
 
 H 4 The 
 
1 04. Some Account of the Blood, 
 
 The fpecific Gravity of thefe Globules is 
 fomewhat more than of the Serum wherein 
 they float, as is fhewn by their fubfiding in 
 Blood extracted from the Veins and at reft : 
 They have alio a considerable Attraction to 
 each other, and when brought in Contact, 
 cohere fo ftrongly ( unlefs foon feparated 
 again by Motion) as to form a Subftance re- 
 fembling foft Fled). 
 
 'Tis not difficult to imagine, how fix foft 
 and flexible Globules, eafily compreflible in- 
 to any Shape, may compofe one larger Glo- 
 bule : but to make it the better underftood, 
 I (hall borrow two Draughts from Mr. 
 Leeuwenhoek. 
 
 Fig. I. Plate X. (hews one fuch large 
 Globule, wherein five of the fmaller fort 
 that compofe it appear in Contact, the fixth 
 lying behind. 
 
 Fig. II. mews, how by their mutual At- 
 traction to, or PrefTure againft each other, 
 they readily unite to form a perfectly round 
 Body. 
 
 It is alfo eafy to conceive, that thefe fix 
 Globules, and even the more minute ones 
 flill whereof they are compounded, may 
 occafionally be feparated, in order to pafs 
 thro' fuch extreamly minute VefTels as with- 
 out Separation they cannot poflibly enter ; 
 and may re-unite when they meet again in 
 VefTels where they have more Room. And 
 we are very certain, that fometimes they 
 2 cohere 
 
■■:'■ '*+ 
 
 fuj.I./i.aoj. 
 
 J '<<7 -K./t ■■*<•+ 
 
 J>/afrX. 
 
 Fy.M./i.uiy 
 
 Tirj IIIL/1.JJ.0 
 
 Fty- V./i. 13 j. 
 
Some Account cf the Bloc J. 105 
 
 cohere in greater Numbers, and form larger 
 Mafles than are confident with a free and 
 healthy Circulation. 
 
 Mr. Leeuwcnhofk and Dr. Jurin af- 
 ter the mod: accurate Admcafurement, by the 
 Way dcfcribcd pag. 3 Jth, agreed, that the 
 Diameter of a common red Globule of hu- 
 man Blood is equal to the * one thou fond 
 nine hundred and fortieth Part of the Length 
 of an Inch. Mr. Leeuwenhoi k before 
 this had computed that -J- twenty-five thou- 
 fand of them were but equal to a Grain of 
 Sand. 
 
 Suppofing, then, the Blood, in People of 
 found Health, to confift of Globules of fuch 
 Size and Compolition as before mentioned, 
 foft, flexile, and cafily feparable ; it mult 
 neceffarily happen, that a coniiderablc Alte- 
 ration in any of thefe Particulars will occa- 
 fion a morbid State. — Should the Globules 
 for Inftance, be divided too minutely, and 
 not readily again cohere j mould they be- 
 come rigid and unflexible, either when fepa- 
 rated or united \ or fhould they coagulate and 
 
 *Vide Philofopb. Tranfafi. Numb. ic6. 
 
 f If the Diameter or' one thoufand nine hundred and 
 forty Blood-Globules be equal to the Length of one Inch ; 
 and if, as Geometricians demonftrate, Spheres be to each 
 other as the Cubes of their Diameters, it mud neceffarily 
 follow, that a Sphere whofe Axis is one Inch in Length, 
 mult be equal to feven thoufand three hundred and one mil- 
 lions, three hundred and eighty four thoufand fuch Globules. 
 
 become 
 
ic6 Some Account of the Blood. 
 become infeparable, bad Confequences mult 
 enfue. 
 
 The great Boerhaave fays, that Health 
 confiilsinan equal Motion of the Fluids, and 
 an equal Refiftance of the Solids. Now the 
 Fluids move equally when their Force is no 
 greater in one Part than another : and the 
 Refiftance of the Solids is equal, when they 
 comprefs the Fluids every where fo equally 
 that no Senfe of Pain arifes. 
 
 But when the Globules of the Blood co- 
 here in MafTes too large, and will not eafi- 
 ly be fo feparated as to pafs freely thro' the 
 minuteft VefTels, the Force of the Fluid 
 muft there be greater, and confequently un- 
 equal j the Refiftance of the Solids muft al- 
 fo be thereby increafed, and rendered like- 
 wife unequal : whence fome Diftemper muft 
 arife. If, on the other hand, the Globules 
 are broken, or feparated into fmaller MafTes 
 than the natural Standard Size, they will 
 take up more Room than they did before ; 
 and, being crowded too abundantly into the 
 capillary VefTels, will occafion Diftenfion, 
 Uneafinefs, and perhaps a partial Stagnation 
 there ; whilft, in the larger VefTels, the Cur- 
 rent rolls along with too great Rapidity, the 
 Force of the Fluids, and the Refiftance of 
 the VefTels are both rendered unequal, and 
 the Ballance between the Solids and Fluids 
 is entirely overturned. None of the Secre- 
 tions in this State can duely be performed, 
 
 and 
 

 Some Account of the Blood. 107 
 
 and unlefs fome means be found to reftore 
 the Equilibrium, the Event rand foon be 
 fatal. 
 
 I believe it will be allowed, that where 
 one Perfon dies from a Diforder in the con- 
 taining VeiTels, Twenty mifcarry by fomc 
 unnatural Alteration in the Fluids that pais 
 through them : and therefore if we can find 
 what their natural State is, the Means where- 
 by it may be preferved in fuch State, by what 
 Accidents it may be prejudiced, and how it 
 may be reflored, our Pains will be well em- 
 ployed. 
 
 In order to obtain this ufeful Knowledge, 
 it will be necefTary to examine the human 
 Blood and other Juices, frequently, with the 
 Microfcopejn every Condition,and under eve- 
 ry Dillemper, as well as in a State of Health: 
 by which we mall have ocular Demonftration 
 of its different Appearances in each State, and 
 of the Changes it undergoes ; and by Expe- 
 riments of various Mixtures with it,* may 
 poffibly difcover by what means it can be al- 
 tered from one Condition to another; as from 
 a thin and broken to a more firm and con- 
 fident State, and fo on the contrary. 
 
 Would our learned Phyficians, who are 
 beft able to judge of fuch Matters, be in- 
 duced to take this Method into their Prac- 
 tice, it is reafonable to believe, that in a few 
 
 Years 
 
io8 Some Account of the Blood. 
 Years the Caufes of Difeafes would be bet- 
 ter known, and the Art of Healing brought 
 to a much greater Certainty than it is at 
 prefent. An Obfervation of Mr. Leeu- 
 wenhoek is very well worth regarding : he 
 took notice, that when he was greatly difor- 
 dered, the Globules of his Blood appeared 
 hard and rigid, but grew fofter and more 
 pliable as his Health returned : whence he 
 infers, that in an healthy Body it is requi- 
 fite they mould be foft and flexible, that they 
 may be capable of parting through the ca- 
 pillary Veins and Arteries, by eafily chang- 
 ing their round Figures into Ovals, and alfo 
 of re-aflli mine their former Roundnefs when 
 
 o 
 
 they come into VefTels where they find lar- 
 ger Room. 
 
 Changes are produced in Fluids furprizing- 
 ly and fuddenly, as a very few chymical 
 Experiments will demonftrate : the Bite of 
 Venomous Creatures, and Inoculating for the 
 Small Pox, mew likewife, how minute a 
 Proportion of poifonous Matter will conta- 
 minate the whole Mais of human Blood -, 
 which can no otherwife be effected but by 
 altering the Solidity, Figure, Size, or Motion 
 of its component Parts or Globules. And 
 it is probable, that in many Cafes, it may be 
 changed from a morbid to a healthy State, 
 by ways not lefs eafy, could we be fo happy 
 as to find them out 5 for we cannot reafon- 
 
 ably 
 
Some Account of the Blood. icy 
 
 ably fuppofe, that the beneficent Author of 
 Nature has given more certain and ready 
 Means of doing Mifchief than of doing 
 Good. 
 
 Many Diilempers might perhaps be cured 
 by an immediate Admiflion of fome Medi- 
 cines into the Veins, which elude the Power 
 of all that can be taken by the Mouth. For 
 the Stomach, by its Heat, its Action, and 
 a Mixture of its Juices, works fuch an Alte- 
 ration in things, before they can be admit- 
 ted into the Blood, that they are unable to 
 produce the fame Effects as if they were re- 
 ceived into it fimply and unchanged. 
 
 Some Trials that have been made already 
 may ferve in a great meafure towards con- 
 firming the above Supposition. Dr. Fabri- 
 cius injected with a Syphon into the Me- 
 dian Vein of a Soldier's Right Arm, in the 
 Hofpital at Dantzick *, about two Drams 
 of a certain purgative Medicine, which in 
 about four Hours began to operate, and gave 
 the Patient five Stools. His Cafe was Ve- 
 nereal, and in fo terrible a Manner, that 
 there were Nodes on the Bones of his Arm. 
 But by this iingle Injection, and without 
 any other Medicine, the Protuberances gra- 
 dually difappeared, and the Difeafe was quite 
 cured. He likewife injected into the Vein 
 
 Philofjph. Tranfaftions, N" 1 - 30 
 
 0( 
 
1 1 o Some Account of the Blood. 
 
 of a married Woman, thirty-five Years old, 
 and troubled from her Birth with Epileptic 
 Fits, a fmall Quantity of a purging Rozin dif- 
 folved in an Anti- Epileptic Spirit: this oc- 
 cafioned a few gentle Stools - } after which 
 the Fits were lefs violent every time than 
 other, and in a fhort Time returned no 
 more at all. 
 
 Dr. Smith "f-, of the fame City, injected 
 Alteratives into the Veins of three Patients ; 
 one was lame with the Gout, another ex- 
 ceedingly Apoplectic, the third afflicted with 
 that ftrange Diftemper, called the Plica 
 Polonica ; and they were all cured by the 
 faid Injections. 
 
 S. Fracassati in]ed:edAqiia Fortis'mto 
 the jugular and crural Veins of a Dog, which 
 died immediately. The Blood was found fixed 
 in the fmaller VefTels, and the larger Veffels 
 burft. Whereupon he remarks, that as an Apo- 
 plexy is caufed bv a Coagulation of the Blood, 
 it may probably be cured by fome Dijjohent 
 
 injected Another Dog, in whofe Veins 
 
 Oil of Vitriol was injected,complained a great 
 while, foamed like Epileptics, breathed fhort, 
 and died. His BIcod was fixed and gru- 
 
 mous, refembling Soot. Oil of Tartar 
 
 was injected into a third Dog, who after 
 much bemoaning, appeared fwell'd, and died. 
 
 •f- Philofoph. Tranfa£tions, Numb. 39. 
 
 His 
 
Some Account of the Blood. 1 1 1 
 
 His Blood was not in the leaft curdled, but 
 
 thinner and more florid than common. 
 
 This proves too great a Separation as well as 
 a Coagulation mortal. 
 
 Mr. Boyle found, that by putting a little 
 Aqua Fortisy Oil of Vitriol \ or Spirit of 
 Salt into warm Blood, it did not only loie 
 its pure Colour and become dirty, but in 
 a Moment was coagulated ; whereas urinous 
 Spirits abounding in volatile Salts, fuch as 
 Spirit of Sal Armoniac, mingled with it, 
 did not curdle it, or debafe its Colour, but 
 made it redder, kept it fluid, and preferv- 
 ed it a long while from Putrefaction. 
 
 As the Microfcope has informed us of the 
 Structure oftheBlood, which without its Help 
 could never have been difcovered, and as 
 its continual AfTifiance is needful to examine 
 and diftinguifh minutely any Changes that 
 may be wrought therein, either for the bet- 
 ter or the worfe, by Accident or by Medi- 
 cine ; I hope this Diicourfe will not be judg'd 
 too long, or foreign to my Subject, fince 
 Hints of this Kind may prove highly bene- 
 ficial to Mankind, if they fhould be fo for- 
 tunate to fall into the Hands of thofe who 
 are inclinable to purfue and improve upon 
 them. 
 
 I come now to defcribe the Manner of 
 bringing the Blood to a ftridt Examination 
 
 before 
 
H2 Of 'viewing the Blood 
 
 before the Micro/cope, and (hall offer fuch 
 Ways as I have myfelf experienced,not doubt- 
 ing but the Ingenious will contrive others, as 
 they may find Occalion. 
 
 CHAP. VIII. 
 
 Of viewing the Blood with the 
 Microscope. 
 
 TAKE (with the Tip of a Feather, or a 
 foft hair Pencil) a fmall Drop of warm 
 Blood immediately from the Vein, fpread it, 
 as thin as poflible, on the cleared fingle Ifin- 
 glafs placed in a Slider on purpofe, and ap- 
 ply it to the firft or fecond Magnifier : the 
 Globules will then be feen diftinctly, and a 
 little Practice will enable to form a judg- 
 ment of any Alteration that may happen in 
 the Size, Figure, Colour, or Appearance of 
 them. We may alfo examine the Blood ex- 
 treamly well, by taking up a little of it in a 
 very fmall capillary Tube of the thinneft 
 Glafs, and then placing the Tube before the 
 Magnifier. 
 
 If a Drop of the fame Blood be diluted 
 with warm Water, and applied in either of 
 the above Ways, fome of the larger Globules 
 will appear more afunder, and a great many 
 of them will be feen divided into the fmaller 
 ones which compofe them. 
 
 If 
 
with the Mlcrvfcopc. j 1 2 
 
 If fome of the fameB'ood be mixed with 
 a little warm Milk, feyeral red unbroken 
 Globules will be ken diftincllv; but thofe 
 that are again feparated into their fmaller 
 ones will be confounded with the Milk it- 
 felf, of which the greateft Part is nothing 
 elfe but Heaps of fuch like-liz'd minute 
 Globules. 
 
 If we defire to try by Experiment what 
 Alteration any Liquor, either poifonous or 
 meiicinal, can produce on the Contexture 
 of the Blood, the Liquor ihould be blended 
 with it at the very Inftant of its iffuing from 
 the Vein : for if the Blood be in the leaft 
 coagulated before huh Mixture, no certain 
 Conclufions can be formed. Putting the 
 Veflel into which we receive it into a Balbn 
 of Water a little hotter than the Blood, will 
 preserve it longer fluid, and make our Ex- 
 periment by any Mixture with it fucceed the 
 
 better. 1 would alio adviie, to s^et vour 
 
 Infrrument in perfect Readinefs, by adjur- 
 ing the Magnifier before the Vein is opened ; 
 and likewile to make your Observations in 
 a warm Place, left the Blood become con- 
 gealed before you can finifh your Enquiry. 
 
 In all Enquiries of Confequence, it is beft 
 to draw the Blood from a large Vein : be- 
 caufe what we can gain (by the Prick of a 
 Pin or Needle) from the Finger or any fuch 
 Part, ifiues from feme extreamly minute ca- 
 pillary Veflels only, and perhaps is not fo 
 
 I good 
 
1 1 4 Cf viewing the Blood 
 
 good a Sample of the Contexture of the 
 
 whole Mafs. Some Trials on both may 
 
 however not be amifs, to difcover what Dif- 
 ference there is between them. 
 
 Bv mingling with the Blood the lead ima- 
 ginable Quantity cf the poifojious'J 'nice which 
 iflites from the Teeth of a Viper when enra- 
 ged, or from any other Animal^ Vegetable^ 
 or Mineral, we mail difcover its immediate 
 Effect upon the Globules ; and by conlider- 
 ing, that the Alteration we obferve is wrought 
 in it, tho' at reft, we mail be able to judge 
 and calculate what Confequences mull enfue 
 from fuch a Mixture with the Blood, as it 
 circulates through the Veins of a living 
 Creature. 
 
 Mr. William Cowper examining a 
 Solution of Opium with the Micro/cope, found 
 its diffolved Particles in the Shape of fringed 
 Globules : whence he concludes, that fuch 
 Particles circulating in the Mafs of Blood, 
 may be fo entangled in its Serum, or thicken 
 it in fuch a Manner, as to retard its Veloci- 
 ty when over-violent, and render its Motion 
 calm and equal; whereby all painful Senfa- 
 tions will be taken off. And from the fame 
 Principles it is eafy to account for all its o- 
 ther Effects, and how too great a Number 
 of fuch fringed Globules rnuft caufe a total 
 Stagnation of the Blood, and confequently 
 kill. Vid. Philoj: Tranf. Numb. 222. 
 
 Spirits, 
 
with the Micro fcope. 115 
 
 Spirits, Oils, i Suits, Ti:i5lnrcs y 
 
 Effences, and all other chymical Preparations 
 fbrnifh us with numberlefs Subjects of 
 periment; and are certainly capable ol pro- 
 ducing the moil: fudden and amazing Ef- 
 fects, either good or bad, if injected mto the 
 Blood- Veifels of living Animals : theCaufes 
 of which Effects may in a great Degree be 
 discovered and accounted for, by microfcopi- 
 cal Obfervations on Mixtures of them v. 
 the Blood when extracted from the Veins. 
 
 A little Blood beins: mixed with about 
 four Times its Quantity of *ScU Volatile 
 Oleofum, and viewed through a M:cro/ccpe y 
 there appeared an immediate Separation of 
 the Globules. In about the eighth Part of 
 a Minute fome of them w^re much dimi- 
 nim'd, and in a quarter of a Minute many 
 of them were much diiTolved and entirely 
 difappeared. Sometimes twenty Globules 
 were ictn near together, which foon lelTen'd 
 to eighteen, then to iixteen, and became 
 fewer and fewer till only two or three were 
 left. Whence it is probable, that Sal Vo- 
 latile Oleofum taken with the Food, and fo 
 carried into the Lacteals and Blood Veffels, 
 may retain its Power of preventing fuch Co- 
 agulations as would otherwise happen. 
 
 * Arc. Nat. Tom. IV. page 36. 
 
 I 2 The 
 
1 1 6 Of viewing the Blood, Sec. 
 
 The Urine, Saliva, Semen, Sweat, Faces 
 Afoi, and all other Animal Juices, are like- 
 wile Objects for the Microlcope j to be ex- 
 amined either alone, or mixed with the afore- 
 faid Liquors : whence much ufeful Know- 
 ledge may be acquired. . 
 
 As to Colour in the Blood, a Blacknefs a- 
 rifes in it from a Deficiency of Serum, as 
 Palenefs does from too great an Abundance 
 of it : for it will be always found, that 
 when Globules cohere together in too great 
 Numbers they give a black Appearance. 
 When this therefore is the Cafe, means of 
 diluting fhould be found out, and made ufe 
 of j fince it is abfolutely requisite to Health, 
 that the Globules of the Blood mould float 
 in a due Quantity of Serum, and be there- 
 by circulated freely through the minuted 
 Veflels, a contrary State to which has prov'd 
 
 the Death of thoufands. Mr. Leeu- 
 
 we-nhoek tell us, that whenever he found 
 his Blood too deep colour'd, his Way was 
 to drink four Difhes of Coffee in a Morning, 
 in the Room of his ufual two ; and fix Dimes 
 of Tea in the Afternoon, inftead of three. 
 He drank it as hot as poffible, and went on 
 in this Mariner, till he perceived his Blood 
 grow paler, and confequently its Globules 
 farther feparated. 
 
 CHAP. 
 
t "7 ] 
 
 C II A P. IX. 
 
 The Circulation of the Blood. 
 
 IN order to view the Blood circulating 
 through its Vtffcls, we muff make uie cf 
 fuch /mail Creatures as bv their Tranfpa- 
 rency permit us to look within them, and 
 fee what paries there : for, in a Man, or any 
 of the large Animals, the Skin is fo opake, 
 that we cannot difcern even the fine Blood- 
 VefTels themfelves, and much lefs the Cur- 
 rent that runs along them. Our Informa- 
 tion, however, will not be greatly different ; 
 for the whole Animal Creation is ellablifhed 
 on one and the fame Plan, and the Circu- 
 lations in the meaneft living Creature are 
 carried on through Veffels of a like Structure 
 (in the general) and are accelerated, or re- 
 tarded, by the fame Caufes as in the noblefr. 
 And, in Truth, as to the Circulations of 
 the Fluids, and the Motions of the Bowels, 
 the Brain, or any of the internal Parts, 
 more Knowledge may be gained by infpect- 
 ing Life 3s and Jma U Animals with the Mi- 
 cro/copi\ than by the molt (kilful and curious 
 Diffe&ions, or anatomical Experiments on 
 larger Subjects. For the Skins of fome of 
 thefe little. Creatures are fo tranfparent, that 
 we may fee plainly through them the Order 
 and Diipoiition of the Veffels underneath; 
 I 3 and 
 
1 1 8 'The Circulation of the Blood. 
 
 and the Coats of thefe Veflels are, again, 
 of fiich an amazing Thinnefs and Delicacy 
 oF Contexture, that they are little or no Im- 
 pediment to our View of the fccrer, tho' re- 
 gular, Operations of Nature, and the Laws 
 ihe ads by, when undifturb'd and quiet: 
 whereas our DiiTtctions of larger Animals, 
 whil'. alive, may {hew her at work, indeed, 
 but in fuch Confufidn, by breaking in upon 
 her violently, that all her Motions, then, 
 muff, be in great Difordcr, andconfequently 
 uncapable oi~ affording any fatisfactory Infor- 
 mation as to the Circulations. 
 
 In this Sort of Creatures too, after view- 
 ing, as long as we think fit, the natural and 
 regular Current of the Blood, as it is carried 
 on in a State of Health ; we may by Pref- 
 fure, and feveral other Ways, impede, di- 
 fhirb, and divert its Cotorfe ; and may find 
 Means, by various Mixtures with it, of in- 
 ducing a morbid State ; and at laft, by let- 
 ting the Creature dye before our Glafs, we 
 may perceive all the Changes it undergoes, 
 and what occafions the intermitting, vibra- 
 ting, trembling Pulfe of expiring People. 
 
 In feveral of thefe little Creatures we can 
 not only fee the general Courfe of the Blood, 
 but are able perfectly to diftinguifh the Fi- 
 gure and Circumftances of the Globules 
 whereof it is compounded, and the Altera- 
 tions they naffer, when they pafs out of the 
 larger into the more minute Veflels. For 
 i many 
 
The Circulation of the Blood. 1 1 9 
 
 many of the Veflels are lb fmall, that even 
 fingle Globules cannot pofTibly find a Pailige 
 thro' them without being compreifed into 
 oval Shapes : and yet thefe Veflels arc large 
 in companion of the fined: Vefiels of all, 
 to pais through which, (he Globules muft 
 be divided and fubdivided into their f nail- 
 eft and moil minute component Globules. 
 
 'Tis amazing to obferve, how careful 
 Providence has been to prevent the Blood 
 from coagulating, or cohering in Mafles dan- 
 gerous to Life, by the very Difpofition of 
 the Veflels it runs through : which, whether 
 feparating, or uniting, are ib contrived as to 
 caufe the Globules to come frequently toge- 
 ther with a brifk Collision, or finking a- 
 gairift each other. The Arteries, for Ex- 
 ample, which convey the Blood from the 
 Heart to the Extremities of the Animal, 
 and in their Progrefs continually leffen their 
 Diameters, and divide into fmaller Branches 
 almofl ad Infinitum: in thefe Arteries, I 
 fay, at every fuch Divificn, many of the 
 Globules of the Blood muft rum, with a 
 confiderable Force, againft an Angle direct- 
 ly in their Way j whence recoiling back on 
 thofe immediately behind, they muft ftrike 
 upon one another, and caufe a Kind of 
 Commotion, e'er the Current can divide 
 readily into the two fmaller Branches. See 
 
 Fig III. Plate X. In the Feins, which, 
 
 I 4 on 
 
I 20 Of viewing t!:e Current 
 
 on the contrary, return back the Blood from 
 
 the Extremities to the Heart,* whole Diame- 
 ters enlarge as the Tide rolls along, and 
 Whole fmali Brandies arc continually uni- 
 ting and making larger VeiTels, till at laft 
 all their Streams fall into one j here, at every 
 Conjunction of two Branches, their Currents 
 rufh againft each other with Violence: by 
 which Concuffion unnatural Cohefions are 
 broken, or prevented j and of this the Mi- 
 crcfiope can afford us ocular Demonftration. 
 Vide Fig. IV. 
 
 CHAP. X. 
 
 Of viewing the Current and the Circulation 
 of the Blood. 
 
 "pY the Current of the Blood, I mean, its 
 ■*- J> ft reaming or puffing on either from or 
 towards the Heart , through any Feffe/ y whe- 
 ther \t be a Fein or Artery. 
 
 By the Circulation I would be underftood 
 to intend, the Courfe or Current of it, from 
 the Heart along the Arteries to the Extre- 
 mities of ih.^ Body : together with its Return 
 by the Feins from the Extremities back 
 again towards the Heart. 
 
 Both thefe the Micro fcopc can bring to 
 
 View i but the latter is fomewhat more dif- 
 
 I ficult 
 

 and Circulation of- the Blood. 121 
 
 ficult to be allured of than the former ; for 
 when the Veuels before us are extreamly 
 lmail, it is not always eaiy to diftinguiflU 
 which of them are Veins and which arc 
 Arteries. ^ 
 
 The larger Arteries are indeed diftinguifli- 
 able by a Protrufion of the Blood at each 
 Contraction of the Heart, then a Stop, and 
 then a new Protrufion, which may plainly 
 be ken continually fucceeding one another : 
 whereas the Current pafles through the Veins 
 with an equal and unintermitting Stream. 
 But in the more line and extreme Branches 
 of the Arteries this Difference is not per- 
 ceivable. 
 
 The tranfparent Membrane between a 
 Frog's hind-foot Toes is the Object molt 
 commonly employed for viewing the Current 
 and Circulation of the Blood - y and, in this, 
 if well expanded, it may be fecn fairly and 
 diftinctly, both in the Veins and Arteries, id 
 the manner reprefented Plate XI. Fig. I. 
 
 A. A. two Toes of a Frog's hinder Foot. 
 
 B. the thin Membrane between the Toes > 
 extended. 
 
 C. C. C. the Trunks of the Arteries. 
 
 D. D. the Trunk of a Vein. 
 
 E. E. E. Arteries and Veins in the fine 
 Membrane, with the Blood-Globules circu- 
 lating through them. 
 
 The 
 
122 Of viewing the Current 
 
 The Way of applying it to the Microfcope 
 was defcribed Page 1 3 ; and therefore needs 
 not be repeated here. 
 
 The Tuils or Fins of fmr.ll Fi-'hes may 
 likewife be ufed very commodio'jfly to this 
 Purpofe, and prefent to View great Num- 
 bers of Veins and Arteries with the Blood 
 pafling different Ways through them. 
 
 It is difficult here in London to meet with 
 any Fifties alive and proper for this In- 
 fpection, except Eels and Flounders : either 
 of thefe will ferve however exceeding well ; 
 
 but the fmailer they are the better. Put 
 
 your Eel into a GlafsTube fill'd with Water, 
 after wiping off its Slime, which would ob- 
 fcure your Glafs. Then having flopped 
 both Ends, to prevent the Water's running 
 out, apply the Tail or Fin to your Micro- 
 fcope, and you'll fee the Circulation in a very 
 agreeable Manner. If you put not Water 
 in your Tube, the Sliminefs of the Eel will 
 immediately foul the Glafs and prevent your 
 Pleafure. 
 
 The flat Figure of the Flounder will not 
 permit us to put it in a Tube as we do the 
 Eel, or view it by every. Kind of Micro- 
 fcope : but if a plain Piece of thin Glafs be 
 placed over the Hole, where Objects are ap- 
 plied to the Double Reflecting Microfcope, 
 its Tail may be fpread advantagioufly upon 
 the faid Glafs: and by fetting a Book, or 
 
 fome- 
 
/ ha. /-'/. 
 
 A. 
 
 Ti^.JI.v. 124. 
 
 ffi:l 
 
 jFu/.JII.p./43 
 

and Circulation of the Blood. 123 
 
 fomething elfe of a proper Height to flip- 
 port the Body of the Fim, it will lye in a 
 very good Pofition for View, and the Circu- 
 lation may be ilen ditlinctly. 
 
 Eels and Flounders live a long while out 
 of Water, and are therefore molt ufeful for 
 this Service here at London; but in the 
 Country many Sorts of other fmall Fidies 
 may be found much more tranfparcnt. 
 
 Mr. Le e u w e n 11 o e k informs us * that 
 he {d\v, with great Admiration, in the ut- 
 most Extremities of a very minute Fifli's 
 Tail, how the larger Arteries were there di- 
 vided into the mofl fine or evanefcent ones ; 
 and how many of the fmallefl Veins, re- 
 turning from the (aid Extremities, met to- 
 gether at la ft in fome larger Vein. There 
 appeared alfo in fome Veficls, fuch an Agi- 
 tation of that Blood (which was protruded 
 from the larger Arteries towards the eva- 
 nefcent Ones at the very Extremity of the 
 Tail, and returned afterwards through ma- 
 ny minute Veins into a large One) as hardly 
 can be conceived. In the larger Arteries he 
 could perceive a continual new Protrulion, or 
 Acceleration of the Blood's Courfe, received 
 from the Heart ; but in the fmaller Arteries 
 the Motion feemed equable, without any 
 
 Ai can. Nat. Tom. IV. Epift. 65. 
 
 fuch 
 
124 Of viewing the Cur twit 
 
 fuch repeated Propulfion : and though in the 
 minuteft VefTels there appeared no Colour, 
 yet in the larger Vein or Artery, though 
 near the End of the Tail, the Blood was 
 plainly red. 
 
 We cannot properly call any VefTe! an 
 Artery farther than the Puliation reaches ; 
 beyond that, and returning towards the 
 Heart, it muft be accounted a Vein : for 
 Veins are onl^ r Arteries elongated; but as 
 they frequently divide into Branches that 
 evade Difcovery, it is, perhaps, impo fable 
 to determine exactly where the Arteries end, 
 and where the Veins begin. 
 
 They do not always, however, branch 
 out fo extrearnly fine before their Inofculati- 
 on or Communication with the Veins ; for 
 the fame curious Obferver tells us, that on 
 each Side the little Grilles, which gave a 
 Stiffnefs to the Tail of the Filh abovemen- 
 tion'd, he could fee a very open Communi- 
 cation of the Veins and Arteries : the Blood 
 running towards the Extremities through 
 Arteries, and returning back again thro' 
 Veins that were evidently a Continuation of 
 thofe Arteries, and of the fame Diameter 
 with them : And this he law in thirty-four 
 different Places, in as many Arteries, and as 
 many Veins. The Manner whereof, as by 
 him delineated, is (hewn, Tab. XI. Fig. II. 
 
 A. A. 
 
and Circulation of the Blood. 125 
 
 A. A. Reprefent two Arteries, one of 
 which runs on each Side a minute Griftle. 
 
 B. B. Their open Communication with 
 the two Veins C. C. 
 
 As this whole Fim was not half an Inch 
 in Length, how fmall mutt the Tail there- 
 of be, in which, notwithstanding, the Cir- 
 culation of the Blood was vifible in thirty- 
 four Places, and the Current of it in lixty- 
 cight Veflcls ! * and yet thefe Veffels were 
 very far from being the moit minute of all. 
 How inconceivable then mull be the Num- 
 ber of its Circulations in an human Body! 
 Nor need we wonder to behold it iifuing 
 forth at everv Prick of a Pin or Needle. 
 Upon conlidering this, Mr. Leeu wen- 
 hoe k adds, that he is fully perfuaded, a 
 thoufand different Circulations of the Blood 
 are continually carried round in every Part of 
 a Man's Body that is not larger than the 
 Breadth of his Fore-finger Nail *. 
 
 The Tail of a Newt, or Water-Lizard, 
 applied in a Glafs Tube, after the Manner 
 directed for the Eel, affords an entertaining 
 Profpedt of the Circulation through Num- 
 bers of fmall Veffels. But nothing can mew 
 it finer, than an exceeding fmall -j- Newt of 
 
 * Leeuwenh. Arcan. Nat. Tom. IV. p. 169. 
 f Phil. Tranjail. Numb. 2SS. 
 
 this 
 
126 Of viewing the Current 
 
 this Water-Kind, which fometimes may be 
 found lefs than an Inch long, and i"o tranipa* 
 rent, that the Blood may be feen running in 
 all Directions, not only through theVeflels of 
 the Tail, but throughout the whole Body : 
 And it is particularly delightful, to behold, in 
 the little Toes, the Stream thereof running to 
 the Extremity in one Channel, and return- 
 ing back again by another. J ml below the 
 Head are on either Side three*Fins, or fome- 
 what like them, which, in fwimming, the 
 Creature makes Ufe of to poife and guide its 
 Body : each of thefe appears by the Micro- 
 fcope divided, like Polypody, into many point- 
 ed Branches ; in any one whereof, as in the 
 Toes, the Blood is feen coming along an Ar- 
 tery to the Extremity, and then immedi- 
 ately returning towards the Heart again, 
 through a Vein that lies parallel, and almoft 
 clofe thereto, and with which its Commu- 
 nication is very apparent. — As thirty or forty 
 of thefe Branchings prefent themfclves be- 
 fore the Eye fometimes at once, with the 
 Blood diftinctly circulating in all, they afford 
 a charming Sight : and they may be viewed 
 by the third or fourth Magnilier j for the 
 Globules of the Blood in Newts are larger 
 than in any other Creature I have examin'd, 
 and are fewer in Proportion to the Serum or 
 Water they float along in. To which I may 
 alfo add, that the Figure of them, as they are 
 
 carried 
 
and Circulation cf the Blood. 127 
 
 carried along the Veffels, changes in a mofl 
 furprizing Manner. 
 
 In Spring-time, if a little Frogs Spawn 
 be kept fome Days in a fmall Quantity of 
 the Ditch Water wherein you found it, you'll 
 be furnifhedwith a Number of exceedingly 
 fmall Tadpoles, which, when firft they be- 
 gin to fwim are almolt wholly tranfparent: 
 and if placed before the Miciofcope, in a 
 Tube proportionably fmall, with fome Water 
 in it, you'll eafily difcern the Heart and its 
 Puliation, together with the Blood circulat- 
 ing in every Part of the Body ; and, particu- 
 larly, in the Tail, more than fifty VefTels 
 prefent themfelves at one View. 
 
 Thefe Tadpoles become lefs clear every 
 Hour, and in a Day or two their Skin grows 
 fo opake, that the Circulation of the Blood 
 can be feen no longer, unlefs it be in the 
 Tail, or better mil in the Fins, at the joining 
 on of the Head. 
 
 A fmall Mujcle taken carefully from its 
 Shell, and placed before the Microfcope on 
 an Ifinglafs, affords a View of many Arte- 
 ries and Veins, through which the Circula- 
 tion of the Blood may be very clearly fecn : 
 and one great Advantage in this Object is, 
 that it lies always quiet ; whereas molt other 
 Creatures are difficult to be kept (till long 
 enough for Obfervatioh. The Motion of the 
 
 Blood 
 
128 Of viewing the Current 
 
 Blood continues in it fix or feven Hours with 
 little Alteration : and, by moiftening it now 
 and then with fait Water, may probably be 
 continued much longer. 
 
 I can alio allure you, from my own re- 
 peated Experiments, that if a large Mufcle 
 be carefully opened, and a Piece of the, thin 
 tranfparcnt Membrane adhering to the Shell 
 be fnipped off with a Pair of (harp Scillars, 
 and applied to the Microfcope, the Blood 
 will be {ten palling through Numbers of 
 Veins and Arteries ; and if the Extremity of 
 the Membrane be viewed, the true Circula- 
 tion, or the Return of the Blood from the 
 Arteries through the Veins, will be fhewn 
 in a delightful and fatisfa&ory manner, and 
 continue for a long Time. There are like- 
 wife other tranfparcnt Parts of the Mufcle, 
 where the Paffage of the Blood is very dd- 
 cernable : And, as MuJ'cles are to be got mod 
 times of the Year in London, the Knowledge 
 hereof will, I hope, oblige the Curious. 
 
 We are told by Mr. Leeuwenhoek, 
 that in the farther! Joints of the hinder Legs 
 of little * Crabs, he beheld the Blood circu- 
 late through the Arteries and Veins, with 
 greater Rapidity than he had ever obferved it 
 in any other Creature ; and, moreover, that 
 the red Globules thereof were twenty-five 
 
 * Leeuw. Arc. Nat. Tom. IV. Ep. 84. Again, Ep. 86. 
 
 times 
 
atid Circulation of the Blood. 129 
 
 times fewer in Proportion to its Serum than 
 in any other Land or Water-Animal he had 
 ever before examin'd. 
 
 At the proper Time of Year, exceeding 
 fmall Crabs may be found, in great Abun- 
 dance, under Stones and Brick-bats on the 
 Shores of the River Thames, when the Tide 
 is out : and as many of them are not larger 
 than a little Spider, it is highly probable 
 iuch may be tranfparent in many Places of 
 the Limbs and Body ; notwithstanding Mr. 
 LeeuwEiNHoek: found his, which were an 
 Inch broad, opake every where but in the 
 extreameft Joints of the hinder Legs. Per- 
 haps too, they may appear more tranfparent, 
 if thev are applied to the Microfcope in a 
 little Tube filled with Water, than if they 
 are viewed dry ; for 'tis obfervable, that 
 many Objects acquire a Tranfparency by be- 
 ing wetted, in the fame manner as Paper 
 becomes clear by being rubbed with Oil. 
 
 The Blood may be feen circulating in the 
 Legs and Taib of Shrimps, especially if view- 
 ed in Water ; but then the Water mult 
 have a little Salt put thereto, or elfe they 
 will foon expire. In Shrimps the Blood is 
 not red ; which has given Occafion to call 
 them as well as many odier Iniacls exangues f 
 or bloodlefs : tho' in reality no living Crea- 
 ture is without Blood ; for animal Life con- 
 filts in a Circulation of fome Fluid through 
 K Arte,- 
 
130 Of viewing the Current 
 
 Arteries and Veins, and that Fluid, what- 
 ever Colour it may be of, is properly to be 
 accounted Blood. In GraJJjoppers the Glo- 
 bules (which may be feen pafling through 
 the Vellels in their Wings) are green, and 
 yet I am apt to think, no body that views 
 them will hefitate to call them, with the 
 Serum wherein they fwim, Blood. 
 
 In the tranfparent Legs and Feet of feve- 
 ral fmall Spiders, the Current of the Blood 
 may plainly be diftinguiuYd both in the 
 Veins and Arteries : alfo in the Legs of very 
 fmall ~P unices or Bugs it is remarkably vifi- 
 ble, together with an extraordinary Vibra- 
 tion of the VefTels, which I never have ob- 
 ferved in any other Creature. In thefe too, 
 if clear, as they may fometimes be found, 
 the wonderful Motions of all the internal 
 Parts will afford an agreeable Entertainment 
 to the Curious, and may be examin'd as long 
 and as often as they pleafe. For I have kept 
 a Bug alive in a Slider between two Pieces 
 of Innglafs at leaft fix Weeks together, not- 
 withfianding it was confined fo clofe as to 
 be uncapable of ftirring : and al'ho' during 
 that time it often feem'd dead and motion- 
 lels, when I placed it before the Microfcope 
 a little Warmth would fet the Bowels at 
 work rgain, and renew the Current of the 
 Blood as brifkly as ever. 
 
 After 
 
and Circulation of the Blood. 131 
 
 After many Obfervations made by Mr* 
 Leeuwenhoek on the Blood of Cofks* 
 Sparrows, Frogs, Trout, Perch, Cod, Salmon, 
 &c. he affirms, that the red Particles in the 
 Blood of Birds, Fijl:es } and Water- Aii .. 
 are confhntly * flat and of an oval Figure, 
 that is, they are longer than their Breadth, 
 and appear as in Plate X. Fig. V. The fe- 
 rous Part of the Blood in Fijles and Aquatic 
 Animals is alio greatly more, in Proportion 
 to the red Particles, than it is in Beafls or 
 Men, and the Particles themfelves are larger : 
 ib that, by being bigger, and iwimming far- 
 ther afunder, they may be iQcn much better. 
 
 Mr. Leeuwenhoek obferved the Blood 
 circulating in the filmy Wings of a -J- Bat, 
 and likewise in its Ears, and found the Glo- 
 bules thereof perfectly round : Wherefore, al- 
 lowing his Allertion, that in Filhes and Birds 
 they are always flat and oval, we need no 
 longer heikate how to clais this odd Creature; 
 but, notwithstanding its flying, fhall pro- 
 nounce it to be a Beafl. 
 
 He tells us, that Bats can fee as well by 
 Day as Night : but he fuppofes the Keat 
 and Drynefs of the Day- Air would ihrivel 
 up the thin Membranes of their Wings, and 
 confequently flop the Circulations there: 
 
 * drr. Nat. Tom. I. P TI. p. 51. Aglin, Tern 
 ;8. Again, Tern. IV. Epijl. 65. 
 i Arc. Net. Tom. IV. Epitl .67. 
 
 K 2 whereas 
 
132 Of viewing the Current 
 
 whereas the cool Dews of the Evening ren- 
 der them moift and pliable ; which makes 
 them chufe that time to come abroad. 
 
 In viewing feveral of the Objects here 
 mentioned, one fhall often obferve the Blood 
 palling through VefTels fo minute, that the 
 Globules of it cannot glide along otherwife 
 than Tingle, and fqueezed into oblong Forms: 
 yet an hundred of the red Globules of fuch 
 Blood, if placed clofe to one another in a 
 Row, would not equal the Length of the 
 Diameter of a large Grain of Sand j and 
 confequently a Million of them exceeds not 
 a Grain of Sand in Bignefs *. 
 
 The Effects of Heat and Cold upon the 
 Blood are well worth taking notice of: for 
 as Heat relaxes the VefTels, the Blood finds 
 more Room to move in, its Globules float at 
 greater Diftances, and it circulates more 
 freely ; whereas Cold fo contracts the Vef- 
 fels, that the Globules are* compreft toge- 
 ther, and the Blood is impeded, and in fome 
 Degree coagulated in the minute Capillary 
 Veins and Arteries of the extream Parts j as 
 is evident from the Swelling and Blacknefs 
 of the Hands and Feet when expofed to fe- 
 vere Cold. 
 
 Leeuwen. Arc, Nat. Tom. I. Par. I. pag. 35. 
 
 Before 
 
and Circulation of the Blood. 1 3 3 
 Before I clofe this Chapter, I mail briefly 
 communicate feme Experiments, I had the 
 Pleafure of making laft Summer, with mv 
 molt ingenious and valuable Friend Doctor 
 Alexander STUART,Phyfichn to her late 
 Majefty, in order to view the Circulation of the 
 Blood by the Solar or Camera Obfcura Micro- 
 fcopc, which has the Advantage of magnifying 
 Objects beyond any other fort of Microicope : 
 but muit refer the Curious to a more full 
 Account thereof laid by this Gentleman be- 
 fore the Royal Society, and which will be 
 published in the Pbilofophical Traiifaclions. 
 I mud firft defcribe a particular Apparatus, 
 invented by the DoBor, for examining the 
 Circulation of the Blood in Frogs, Mice, 
 Bats, or any Creatures of the like Size. In 
 this Contrivance, the Looking-glafs, Tube, 
 and convex Lens are juft the fame, and 
 placed in the Hole of a Window-Shutter in 
 the fame manner as defcribed Pag. 22. But 
 here, inftead of ufing Wilson's little Pocket 
 Micro/cope, he has got the Belly-Part of a 
 large Reflecting one fixed horizontally on a 
 Pedeftal, at a Height exactly equal to the 
 Tube. This frauds on a little Shelf made 
 to fupport it j and to the Snout thereof, 
 which lies on a Level with the Tube, the 
 Magnifiers are fcrewed. The Object being 
 extended and fattened with Strings and Pins 
 on a Frame convenient for the Purpofe, is 
 applied between the Tube and the Magni- 
 
 K 3 fier : 
 
134 Of viewing the Current 
 
 fier : whereby the Sun's Rays reflected from 
 the Looking-ghfs, through the Tube, upon 
 the Object, pafs on through the Magnifier, 
 and exhibit upon the Screen an Image of 
 the Object mod prodigiou fly enlarged. This 
 I hope may give fome "Idea of our Inflru- 
 ment: and now I come to the Application. 
 
 Our Object was a Frog, whole Limbs 
 being extended and fattened on the Frame, 
 we opened the Skin of the Belly from near 
 the Anus to the Throat: then giving it a 
 little Snip fide ways both at the Top and 
 Bottom, by flicking a Fifb-Hook in each 
 Corner of the Skin, it was eafily firetched 
 out before the Micro/cope, and preiented on 
 the Screen a mo if beautiful Picture of the 
 Veins and Arteries in the Skin, with the 
 Blood circulating through them. In the 
 Arteries we could plainly perceive the Blood 
 flopping, and as it were receding a little, at 
 each Dilatation of the Heart, and then im- 
 mediately ruming forwards again at each 
 Contraction ; whilit in the Veins it rolled 
 on in a continual Current with inexprefiibJe 
 Rapidity *. 
 
 After considering this as long as we 
 thought needful, we opened the Abdomen, 
 and extending the Mufcles before the Micro- 
 
 * When the Arteries were magnified very much, by re- 
 moving the Screen to a confiderable Diftance, the alternate 
 Expansion and Contraction of their Sides were very vifible 
 and remarkable. 
 
 Z fcope* 
 
and Circulation of the Blood. 1 3 5 
 
 fcope, by the fame Means as we had done 
 the Skin, we had the Pleature of viewing 
 their Structure, which we found to confiit 
 of Bundles of tranfparent Strings or Fibres, 
 lying parallel to one another, and joined to- 
 gether by a common Membrane. Thefe 
 Strings or Fibres appeared through their 
 whole Length made up of minute roundifh 
 Veficles, or, in other Words, feemed like 
 Rufhes divided the long Way, We could 
 not be certain of any Circulation throu ;b 
 the Mufcles, though fometimes we imagined 
 we faw a very flow Motion of fome tranfpa- 
 rent Fluid : but the Object growing dry and 
 rigid, obliged us to leave that Enquiry to a 
 farther Examination. 
 
 We then proceeded to our lafl Experi- 
 ment, which was to draw out gently a Part 
 of the Frog's Gut, in order to apply the Mc- 
 fentery to the Micro/cope: and herein we 
 fucceeded fo happily, that I believe the Cir- 
 culation of the Blood was never before feen 
 in fo dillinct and fine a Manner. No Words 
 can defcribe the wonderful Scene thnt was 
 prefented before our Eyes ! We beheld the 
 Blood pafling through numberlefs Veifels at 
 one and the fame Inftant, in lome one Way, 
 in others the quite contrary. Sever?! of the 
 Veifels were magnified to above an Inch in 
 Diameter, and the Globules of the Blood 
 rolling through them feem'd near as large as 
 Pepper-Corns ; whilft in many 01 the mi- 
 K 4 nuteft 
 
1 3 6 Of viewing the Current, 6cc. 
 nuteft Veffels only finglc Globules were able 
 to find a PafTage, and that too not without 
 changing their Figure into that of oblong 
 Spheroids. We faw here likewife, much 
 better than we had done before, the Pulfa- 
 tion and Acceleration of the Blood in the 
 Arteries, in the Manner before defcribed, 
 and could clearly dillinguiih two or three 
 Veffels lying over one another, with Cur- 
 rents running different Ways. In fhort, it 
 appeared like a beauteous Landfcape, where 
 Rivers, Streams., and Rills of running Water 
 are every where diipeifed. 
 
 During this Examination, we took notice 
 of a Veffel extreamly minute, iffuing from 
 the Side of a larger, and turning backwards 
 from it in a curve Line. We perceived, at 
 unequal Intervals, fomctimes one, fometimes 
 two, and fometimes three colourlefs Glo- 
 bules, dropt or fqueez'd out of the larger 
 VefTel into this minute one, and gliding 
 through it fingly and very ilowly ; which 
 made the Doctor imagine it might be &Je- 
 cretory Duel. We obferved likewife, that 
 as the Animal grew languid and near ex- 
 piring, the Blood in the Arteries would flop 
 on a fudden, feem as it were coagulating, 
 and then run backwards for fome time; 
 after which, it would again recover its na- 
 tural Courfe with a great deal of Rapidity. 
 -— A dueConfideration of thefe Appearances 
 might poffibly account foi the Intermiflions, 
 2 Starts, 
 
The Pulfation of the Heart. 137 
 
 Starts, and Irregularities in the Pulfe of Per- 
 fons near the Point of Death. 
 
 CHAP. XI. 
 
 The Pulfation of the Heart. 
 
 'Hp HIS wonderful Phenomenon mav be 
 ■* fecn diftinctly in feveral fmall Infects, 
 fome whereof I mall here mention, with 
 fliort Directions how to find it. 
 
 Divide a * Bee, particularly an Humble- 
 Bee, near the Neck : and its Heart, which 
 is a white pulfing Particle, may be feen 
 beating brifkly. 
 
 The Head of the J Horfe-Fly being cut 
 off, juft at the fetting on of the Neck, a 
 little Particle (which is the Heart) will ap- 
 pear with a Pulfation in it for half an Hour. 
 
 The -J- Grafshopper has a green Film or 
 Plate over its Neck and Shoulders, which 
 being raifed with a Pin, its Heart may be 
 feen, beating very orderly, for a long while 
 together. 
 
 Cut off the Head of that little flying Bee- 
 tle, known to every Child by the Name of 
 § Lady-Bird, or Cow-Lady : erect it per- 
 
 * Dr. Power's Microfccp. Objh-v. p. 4. J Ibid. 7, 
 
 f Ibid. 24. } Ibid. 30. 
 
 pen die u- 
 
138 The Pulfation of the Heart. 
 
 pendicularly, and you'll fee two fmall black 
 Eyes, each fet between three white Plates 
 like poliuYd Ivory, on one fide two fmall 
 ones, and a large one on the other. Pull 
 off both the cruftaceous and filmy Wings, 
 which cover a tender black Skin, and, re- 
 moving that Skin, the Pulfation of the Heart 
 may be feen beating vigoroufly for twelve or 
 fourteen Hours. 
 
 The Heart of a * Snail is to be found 
 exactly againfr. the round Hole near its Neck, 
 of a white Colour, + and may be feen beating 
 a quarter of an Hour after DhTeclion. 
 
 It may alfo be feen in a Loufe, as I mall 
 mew when I come to defcribe that Crea- 
 ture j and I make no doubt the curious and 
 diligent Enquirer will be able to difcover it 
 in Multitudes of other little Animals. 
 
 The periftaltic Motion of the Stomach 
 and Bowels may be feen very diftinctly in 
 Lice, Gnats, Flies, &c. and a Multitude of 
 other Infects. 
 
 * Dr. Power's Micro/cop. Obfer-vat. p. 36. 
 •J-SwAMMERp. Hiji. Generate des Infeflei, p. 77. 
 
 CHAP. 
 
[ 139 ] 
 CHAP. XII. 
 
 Of the mufcular or fleftiy Fibres of Animals. 
 
 THE flefljy Fibres of the Mufclcs (ac- 
 cording to the Obfervations of Monficur 
 Muvs) are compofed of other fmaller Fi- 
 bres or Fibrils, the Size of a (lender Hair ; 
 five or fix hundred of which Fibrils go to 
 the making up of one flcfiy Fibre, whole 
 Diameter is no more than the twenty-fourth 
 part of an Inch. Each of thefe Fibrils is 
 again compofed of more than three hundred 
 fmall transparent Tubu/i, fo extreamly lien- 
 der, that were one of thofe Blood- Globules 
 (which Mr. Leeuwenhoek fuppofes but 
 the Millionth Part of a Grain of Sand) di- 
 vided into twenty- four Parts, even thefe 
 minute Parts could hardly enter and pafs 
 through fuch exceedingly fmall Tubes. And 
 yet, that they do enter and pafs through 
 them is evident by the Rednefs of the Flefh 
 of Animals. We mull: therefore infer, that 
 the Tubuli forming a Fibril are really hol- 
 low : that the Extremities of the Arteries 
 open into them, and empty there a Part of 
 their Liquor, which is carried back again by 
 the Veins to the Heart : and that the Glo- 
 bules of the Blood are, for this Purpofe, di- 
 vided into Parts inconceivably fmall. * 
 
 * Fid, Phil.Tranf. Numb- 339. 
 
 Mr. 
 
1 40 Of the Mafcular Fibres of Animals. 
 
 Mr. Leeuwenhoek fays, each Mufcular 
 Fibre is compofed of many (mailer Filaments 
 or Fibrils ; which, however minute, he could 
 plainly diftinguim to be vafcular : for, if 
 he cut acrofs their Length, the Light ap- 
 peared through the Mouths of the VefTels ; 
 but if he cut them ever fo little obliquely 
 no Light was to be feen *f\ He found alio, 
 that each Fibril is inverted with a * minute 
 Membrane, which is only a Congeries of 
 Blood- VefTels conveying Juices and Nou- 
 rishment thereto, tho' their Finenefs renders 
 them invifible. It is not, however, to be 
 imagined, that each Fibril has its peculiar 
 Membrane : but that all the Membranes to- 
 gether are like a Net finely fpread, with a 
 Fibril ifluing through each of its Mefhes. 
 
 This Structure of the Fibres he obferved 
 in the Flefh of an Ox, and of a Whale ; 
 but more plainly in that of a Whale, the 
 Beef-Fibres lying more compact and clofe. 
 He alfo found that the Fibres of a Moufe 
 were of the fame Thicknefs as thofe of an 
 Ox, though thirty thoufand Mice are not 
 equal to one Ox in Bignefs : whence he 
 concludes, that the different Size of Ani- 
 mals is intirely owing to the greater or lefs 
 Number and Length of the Fibres J. 
 
 + Phil. Tranf. Numb. 367. 
 
 * Gorter. Medic. Compend. p. 58. eg. Leeuw. Arc 
 Nat. Tom. III. p. 58. % Ibid. 61. ' 
 
 Thefc 
 
Of the Mufcuhir Fibres of Animals. 141 
 
 Thefe flejby Fibres appear through their 
 whole Length encompalTed with circular 
 Wrinkles. If a Thread were twifted about 
 a fine Needle in a Screw-like Form, with 
 fpiral Circumvolutions, lb that each Thread 
 be diftant from another the Diameter of the 
 Needle, it would naturally reprefent the 
 Manner of thefe circular T witlings. And 
 this Difpofition is wonderfully contrived for 
 the ready Dijlenfwn or Contraction of the 
 Fibres : for as a Cord will be diftended or 
 contracted quicker, or Jloiver, in proportion 
 to its Length, the fame muft alio be the 
 Cafe in Animal Fibres ; and, therefore, o;i 
 thefe Principles we may calculate how much 
 more nimbly the Leg of a Moufe can move 
 than the Leg of an Ox. 
 
 The Method of viewing the Mufcular 
 Fibres is, to cut carefully, and with a very 
 lharp Razor or Pen-knife, a Slice ofdryed 
 Flem or Fifh, as thin as poflible. Lay it 
 on a Piece of Glafs, and moiften it with 
 warm Water ; which, drying foon away, 
 will leave the Veflels open and diftinguiih- 
 
 able. It is obfervable that the Fibres of 
 
 Fifh are larger than thofe of Flem. 
 
 That the Mufcular Fibres are vafcular, or 
 made up of little hollow VerTels, is fuppofed 
 by Malpighius, Borelli, GoRTER,our 
 own Countryman Mr. Hooke, who fays, 
 
 they 
 
142 Of the Mufcular Fibres of Animals. 
 they appeared to him like Strings of Pearls; 
 and, very lately, by Dr. Alex. Stuart, 
 in his learned and ingenious Treatife de Mo- 
 tu Mufculorum ; where, from fuch a Struc- 
 ture, and Sy the Influx of the nervous Fluid, 
 he accounts, very reafonably, for the elaftic 
 Force, the Contraction, the Diftenfion, and 
 all the Actions of the Mufcles *. But as 
 thefe Gentlemen differ fomewhat in the Fi- 
 gure of the little Veficles fuppofed to make 
 up the mufcular Fibres, the Curious will do 
 well to examine, with the Microfcope y into 
 this Matter, as carefully as pomble ; and 
 that, by contriving all the Ways they can 
 think of to view the Fibres in living Ani- 
 mals. For, whatever Form the VefTels may 
 have when replete with a nervous or other 
 Fluid, I am afraid, when the Fibres have 
 been dried, or the VefTels collapfe together 
 by not being fupplyed with fuch Fluid, the 
 true Form and Structure of them can never 
 be fully known. 
 
 Our Obfervations, 'tis probable, may be 
 made with moft Succefs on LifeBs, their 
 fleihy Fibres, as Mr. Leeuwenhoek tells 
 us, being no lefs vifible than thofe of larger 
 Creatures : which he fouud, by cutting off 
 and examining the flefhy Parts of the Legs 
 of -\- Flies, Gnats 3 Ants, &c. in all which he 
 
 * Vid. Go rter de Fabrica & Motu Mufculor. Stuart 
 , deMotu Miilc, p, 49. f Arc. Nat. Tom. III. p. 108. 
 
 could 
 
Of Bones. 143 
 
 could plainly diftinguifh the circular Wrin- 
 kles or Circumvolutions encompafhng the 
 Fibres, as they are pictur'd Plate XI. Fig. III. 
 
 CHAP. XIII. 
 
 Of Bones. 
 
 FT PON examining of Bones with a Mi- 
 ^ crofcopc\ their fuperficial Part is found 
 to confift of a great many fmall VerTels, and 
 fome few of a larger Size : which laft, when 
 they come to the Surface of the Bone, ap- 
 pear inverted with either a Membrane or 
 bony Subfbnce perfectly tranfparent. The 
 Infide of the Bone has a fpongy or cellular 
 Subftance, confiding of long Particles clofe- 
 ly united, which are compofed of number- 
 lefs fmall Veffcls, fome running length-ways, 
 and others taking their Courie towards the 
 Sides of the bony Particles, which, not- 
 withstanding their great Number of Aper- 
 tures, are extreamly hard, and lye fome pa- 
 rallel, and others perpendicular to the Length 
 of the Bone. 
 
 Mr. Leeuwenhof.k difcover'd, once, in 
 a fmall Bit of a Shin- Bone, four or five Vef- 
 fels, with Apertures large enough for a Silk, 
 to pafs through ; each whereof feem'd fur- 
 nim'd with a Valve, difpofed in fuch a Man- 
 ner 
 
144 Of Bon 2 s. 
 
 ner as to let out what was contained in the 
 
 VefTel, but fuffer nothing to return into it *. 
 
 " It may pofTibly be conceived by fome, 
 " fays Dr. Grew, that the Bones, at lead 
 " fome of them, are hard at the firfl: : as 
 " Salts and other cryftallizing Bodies are as 
 " hard upon the very firfl Inftant of their 
 w Shooting, as they are when grown into 
 " large Cryftuls. But it is fo far evident 
 " that all the Bones are foft at the firfl, that 
 " I am of Opinion, they are originally a 
 " Congeries of as true Fibres ov fibrous Vef- 
 " fels as any other in the Body j which by 
 * c Degrees harden into Bones, in like Man- 
 " ner as the inmoft VefTels of a Plant do in 
 " time harden into Wood. And as in a 
 " Plant there are fucceffive Additions of 
 " Rings or Tubes of Wood, made out of 
 " VefTels : fo in an Animal, it feems plain, 
 (< that there are Additions fucceilively made 
 " to the Bones out of the fibrous Parts of 
 " theMufcles : efpecially thofe whitefl Fibres 
 " which run tranfverfly, and make the Sta- 
 " men or Warp of every Mufcle. So that, 
 " as in the Bark of a Plant, part of the Vef- 
 ** fels are fucceilively derived outward to the 
 " Rind, and part inward to the Sap, which 
 " afterwards becomes hard Wood j fo, in the 
 " Flefh of an Animal, Part of the white 
 " tranfverfe Fibres are fuccefTively derived 
 
 * PhilofoDh. Tranfaa. Namb. 366. 
 
 " to 
 
Of the Nerves. 145 
 
 f< to the Skin (of which it chiefly confifts) 
 " and Part of them inwardly, making ftill 
 " new Periofteums one after another, as the 
 " old Ones become fo many Additions to 
 " the Bones." * 
 
 Whoever would examine the Bones, muft 
 fhave off, with a (harp Pen- knife, very thin 
 Pieces lengthways, crofsways, and obliquely, 
 and that from the Infide, Outiide, and Mid- 
 dle of the Bone. Apply to the Micro/cope 
 fome of thefe Shavings dry, and Others moi- 
 ftened with warm Water, and thus the Vef- 
 fels will be (ccn in all Directions. But the 
 bell Way of (hewing the bony Structure is, 
 by putting the Bones in a very clear Fire 
 till they are red hot ; then taking them out 
 carefully, you'll find the bony Cells, though 
 tender, perfect and entire : And being now 
 quite empty, they may be viewed with great 
 Eafe and Plea fu re. 
 
 CHAP. XIV. 
 
 Of the Nerves. 
 
 MR. Lf.euwenhoek endeavoured to 
 difcover, by his Mkrofcope i the Struc- 
 ture ot the Nerves, in the Spinal Marrow 
 
 Crew's Rarities q£ Gre/tam College, p. 6. 
 
 L of 
 
146 Of the Ne r ves. 
 
 of an Ox j and faw, with great Delight, that 
 minute hollow VeiTels, of an unconceivable 
 Finenefs, inverted with their proper Mem- 
 branes, and running out in Length parallel 
 to one another, make up their Compofition. 
 And though fome Hundreds of thefe VefTels 
 go to the Formation of the leaft Nerve that 
 can pofiibly be examined, he did not only 
 diicern the Cavities of them, which he com- 
 puted to be three times lefs than their Dia- 
 meters, but, in fome, perceived the Ori- 
 fices, as plainly, as the Holes in a pricked 
 Paper are to be feen when looked at againft 
 the Sun. It requires however great Dexte- 
 rity and Expedition to make this Examina- 
 tion with Succefs j for after a thin Slice of 
 the Spinal Marrow is placed before the Mi- 
 crofcope, in lefs than a Minute's Time it be- 
 comes dry, and the whole Appearance va- 
 nishes *. 
 
 The fame ingenious Enquirer into Nature 
 examined likewife the Brain of feveral Crea- 
 tures, fuch as an Indian Hen, a Sheep, an 
 Ox, a Sparrow, &c. and could there diftin- 
 guifli Multitudes of VefTeis, fo extreamly 
 fmall, that if a -j- Globule of the Blood (a 
 Million whereof exceed not a Grain of 
 Sand in Bignefs) were divided into five hun- 
 dred Parts, thofe Parts would be too large 
 
 * Arc Nat. Tom. III. p. 310. 355. 440. 
 •f Ibid. Tom. I. Part I. p. 30. 
 
 to 
 

 Of the Nerve s. 147 
 
 to pafs into fuch VelTels. He obferved far- 
 ther, % that the VelTels in the Brain of a 
 Sparrow are not finaller than in an Ox ; 
 and argues from thence, that there really 
 is no other Difference between the Brain of 
 a large Animal and that of a fmall one, but 
 only a greater or fmaller Number of VelTels ; 
 and that the Globules of the Fluid pairing 
 through them are in both of the fame Size. 
 
 Though it does not directly relate to Mi- 
 croft opes, I hope I may be excufed for tak- 
 ing Notice here, that in the Year 171 1, Dr. 
 Alex. Stuart made a Dileoverv, that the 
 Nerves are not elaitic, contrary to the O- 
 pinion of all preceding Authors ; and proved 
 it by the following Experiment ; " Laying 
 a Piece of Twine, about four Inches in 
 Length, parallel to the Nerve, Artery and 
 Vein of the Infide of the Thigh in an hu- 
 man Subject, and tying thefe together above 
 and below, as foon as they were cut out of 
 the Body, and laid on a Board ; the Artery 
 and Vein were ieen to contract equally, to 
 the Lofs of a quarter Part of the Length they 
 had in the Body before Exciilon ; but the 
 Nerve continued of the fame Length with 
 the Twine, as in the Bodv." 
 
 % Arc. Nat. Tom. I. Part 1. p. 38. 
 Vid. Stuart's Leftures or. Mufcular Motion in tbt Vem 
 1738. p. 3. 
 
 L 2 CHAP. 
 
1 148 ] 
 
 CHAP. XV. 
 
 Of the Generation of 'Animals and Vegetables. 
 
 TjQuivocal or fpontaneous Generation^ that 
 -*-"' is, a Production of Plants without Seeds, 
 and of living Creatures without any other 
 Parents but Accident and Putrefaction, how- 
 ever abfurd it may feem to us, was an Opi- 
 nion that prevailed, almoft univerfally, till 
 Micro/copes overturn'd it -, by demonftrating 
 that all Plants have their Seeds, and all Ani- 
 mals their Eggs : whence other Plants and 
 other Animals, exactly of the fame Species, 
 are perpetually and unalterably produced. 
 
 Nothing feems now more contrary to 
 Reafon, than that Chance and Najiine/s 
 mould give a Being to Uniformity, Regula- 
 rity, and Beauty : That two fuch unlikely 
 Principles mould produce in different Places 
 Millions of Vegetables of the fame Kinds, 
 and alike, exactly, even in the mod minute 
 Particularities ; or, what is yet more amaz- 
 ing, that dead corrupting Manner, and blind 
 uncertain Chance mould create living Ani- 
 mals, fabricate a Bruin, constitute Nerves 
 iffuing from it, compofe a Contrail: of Muf- 
 cles, furnifa out Eyes, Lungs, a Heart, a 
 Stomach, Bowels, and all other Parts ufeful 
 to fuch Creatures : and that too not after an 
 awkard, flovenly, variable, undefigning and 
 
 unfinifh'd 
 
of Animals and Vegetables . 149 
 
 nnfinifh'd manner; but with a Contrivance, 
 Dexterity, Elegance, Perfection and Con- 
 ftnncy beyond the utmoft Power of Art to 
 imitate. This, however, was the Opinion, 
 not onlv of the Ignorant and Illiterate, but 
 of the mod learned grave Philofophers of 
 preceding Ages ; and would, probab'y, ftill 
 have been taught and believed, had not Mi- 
 cro/copes difcovcred the manner how all thefe 
 Things are generated, and reflor'd to God 
 the Glory of his own amazing Works J. 
 
 The Eye, aflifted by a good Micro/cope y 
 can diitinguifti plainly in the Semen majculi- 
 num of Animals, Myriads of Animalcule* 
 alive and vigorous, though ib exceedingly 
 minute, that, it is computed, three thou- 
 fand millions of them are not equal to a 
 Grain of Sand, whofe Diameter is but the 
 one hundredth Part of an Inch -j- : And the 
 fame Initrument will inform us beyond all 
 Doubt, that the Farina of Vegetables, are 
 nothing elfe but a Congeries of minute 
 Granula, whofe Shapes are conftant and 
 uniform as the Plants they are taken from. 
 
 \ I would ns foon fay, that Rocks and Woods engender 
 St. gs and Elephants, as affirm, that a Piece of Checie ge- 
 nerates Mites. Stags are born and live in Woods, and 
 Mites in Cheefe; but they both owe their Being to that of 
 other Animals. SpeSi.dc la Nat. Eng. Edit. xzmo. Vol. II. 
 p. ... 
 
 f V id. Keil's Anat. 5th Edit. p. 116. 
 
 L 3 And 
 
1 50 Of the Generation 
 
 And as the Seeds of Plants are proved, by 
 repeated Experiments, to be unprolific, if 
 the Farina be not permitted to (lied, it has 
 been fuppofed, that all its Granula contain 
 feminal Plants of their own Kind. 
 
 The Growth of Animals and Vegetables 
 feems to be nothing elfe but a gradual Un- 
 folding and Expansion of their VefTels, by a 
 flow and progreffive Infinuation of Fluids 
 adapted to their Diameters ; untill, being 
 flretch'd to the utmoil Bounds appointed 
 them by Providence at their Formation, 
 they attain their State of Perfection, or, in 
 other Words, arrive at their full Growth. 
 
 'Tis thought probable, according to this 
 Theory, that, in Animals (of the larger and 
 more perfect Kinds at leaf!:) the Semen of 
 the Male being received into the Matrix of 
 ^the Female, fome of the Animalcules it con- 
 tains in fuch Abundance, find an Entrance 
 into the Ovaria, and lodge themfelves in 
 fome of the Ova placed there by Providence 
 as a proper Nidus for them. 
 
 An Ovum becoming thus inhabited by an 
 Animalcule, gets loofen'd in due Time from 
 its Ovarium, and pafTes into the Matrix 
 through one of the Fallopian Tubes. The 
 Veins and Arteries that fattened it to the 
 Ovary, and were broken when it dropp'd 
 from thence, unite with the Veflels it finds 
 here, and compofe the Placenta. The Coats 
 of the Ovum being fwell'd and dilated by 
 % the 
 
of Animals and Vegetables. 151 
 
 the Juices of the Matrix form the other In- 
 teguments needful to the Prefervation of the 
 little Animal, which receiving continually 
 a kindly Nourishment from the fame Juices, 
 gradually ilreiches and enlarges its Dimen- 
 iions, becoming then quickly vifible with all 
 the Parts peculiar to its Species, and is called 
 a Foetus. 
 
 In Plants, which are uncapable of re- 
 moving from Place to Place as Animals can, 
 it was requilite a Repofitory for their Farina 
 fhould be near at Hand, to prevent its being 
 loft : And accordingly we rind, that every 
 Flower producing a Farina, has likewife in 
 i tie If a proper Uterus for the Reception of 
 it : Where the Ova thereby impregnated, 
 are expanded by the Juices of the Parent 
 Plant to a certain Form and Bulk, and then 
 becoming what we call ripe Seeds, they fall 
 to the Earth, which is the natural Matrix 
 for them. 
 
 According to the above Suppofition, a ripe 
 Seed falling to the Earth, is in the Condition 
 of the Ovum of an Animal getting loofe 
 from its Ovary, and falling into the Uterus : 
 And, to go on with the Analogy, the Juices 
 of the Earth fwell and expand the VelTels of 
 the Seed, as the Juices of the Uterus do 
 thofe of the Ovum, till the feminal Leaves 
 unfold, and perform the Office of a Placen- 
 ta to the Infant included Plant, which im- 
 bibing iuitable and futhcient Moifture, gra- 
 
 L 4 dually 
 
152 Of the Animalcules 
 
 dually extends its Parts, fixes its own Root, 
 ihoots above the Ground, and may be faid 
 to be born. 
 
 As Difcoveries made by the Microfcope y 
 of infinite Numbers of Animalcules in the 
 Semen Mafculinum. of all living Creatures, 
 and likewife of a Regularity and Conftancy 
 in the Farina of each Species of Vegetables, 
 analogous to the faid Animalcules in the Ani- 
 mal Semen, have been the principal Means 
 of convincing us that all Things are pro- 
 duced by Parents of their own Kind, accord- 
 ing to the eternal and unalterable Laws efta- 
 bliihed at their firft Creation ; I hope this 
 fhort Account of Generation, before my en- 
 tering upon thofe Subjects, will not be iudg'd 
 improper. 
 
 CHAP. XVI. 
 
 Of the Animalcules in Semine Mafculino. 
 
 T the Beginning of the Year 1678, Mr. 
 Nicholas Hartsoeker, of Rot- 
 terdam, declared in a Treatife of Dioptrics^ 
 by him then published, that it was twenty 
 Years fince he firft began to examine the 
 Semen Mafculinum of ieveral living Crea- 
 tures by the Help of Micro/copes : that, as 
 z far 
 
in Semine Mafculino. 153 
 
 far as he knew, he was the firfr Perfon who 
 had ever done (6 ; that he had found in fuch 
 Semen infinite Numbers of Animalcules, moft 
 exceedingly minute, almoft in the Shape of 
 Tadpoles or young Frogs ; and that he had 
 made this Difcoverv known to all the World 
 in the 30th of the Epk < Eruditorumj 
 
 primed at Paris, in the fame Year 1678. 
 
 Mr. Leeuwenhoek, in the 1 1 3th 
 of his Epiftles, 1 dated January 1678.) is 
 very angry at this Claim ; and aiferts, that he 
 bimfelf firft difcovered the Animalcules in 
 Semine, and fent an Account thereof to the 
 Royal Society in November 1677, as he 
 proves by the Philojophical Trail factions, 
 published in December 1677, and in January 
 and February 1678 : nay, he further affirms, 
 that Letters hud pail between him and Mr. 
 Oldenburg on this Subject in 1674. 
 This Difpute concerns us no farther than as 
 it ihevvs about what Time the Exillence of 
 thefe Animalcules was firtt difcovered, which 
 fome of my curious Readers may perhaps he 
 inquifitive to know. 
 
 The general Appearance or Figure of the 
 Animalcules in the Semen Mafculinum of 
 different Kinds or living Creatures is very 
 much the fame : that is, the Bodies of them 
 all feem of an oblong oval Form, with long 
 tapering flender Tails ifluing therefrom •, 
 and as by this Shape they fome what re- 
 
 femble 
 
154 Of the Animalcules 
 
 femble Tadpoles, they have frequently been 
 called by that Name ; tho' the Tails of them, 
 in Proportion to their Bodies, are much longer 
 than the Tails of Tadpoles are : and it is ob- 
 fervable, that the Animalcules in the Semen 
 of Fifties have Tails much longer and flen- 
 derer than the Tails of thofe in other Ani- 
 mals, infomuch that the Extremity of them 
 is not to be difcerned without the beft 
 GlafTes and theutmoft Attention : their Bo- 
 dies are alfo much fmaller. 
 
 The general Appearance of them as above 
 defcribed, isfhewn Plate XII. Fig. I. 
 
 In the Spring Seafon, at the Time that 
 Frogs engender, upon opening the Tefticles 
 of a Male, and applying fome of the Jeminal 
 Matter before the Microfcope, Multitudes 
 of Animalcules appeared therein, about * one 
 thoufandth Part of the Thicknefs of the Hair 
 of a Man's Head, as nearly as could be com- 
 puted: whence it follows, that a thoufand 
 millions of them would be but equal to a 
 Globe whofe Diameter is the Thicknefs 
 of the Hair of a Man's Head. And there 
 feemed to be ten thoufand of them at leaft 
 for each one of the female Ova. 
 
 The Shape of them is given in the fame 
 Plate, Fig. II. 
 
 * Leeuwenh. Arcan. Nat. Tom. I. P. J. p. 51. 
 
 Upon 
 
JFur.I. /'. is< 
 
 >'7< 
 
 .#?^%, 
 
 Fy.ZI.//. t 5 f. 
 
 llttt 1 
 
 
 
 ^ 
 
 J 7 Wr.f/I./t.z6o 
 
 -Ffy.7Fin.itfo 
 
 F/, r . TT./x if* 
 
 -Fy.TTT./i i£ 3 
 
 Fcq. V.fj. 101 
 
 -P/ati- XH. 
 
in Semine Mafculino. 155 
 
 Upon viewing the Milt or Semen Mafcu- 
 linum of a living Cod-Fifh with a Micro- 
 Jcope, fuch Numbers of Animalcules with long 
 Tails were found therein, that at leair. ten 
 thousand of them were fuppofed to exift in 
 the Quantity of a Grain of S.uid. Whence 
 Mr. Lee u wen hoe k argues, that the Mile 
 of that finale Cod-Fiih contained more living 
 Animalcules^ than there are People alive 
 upon the Face of the whole Earth at one 
 and the fame Time : * for he computes, that 
 one hundred Grains of Sand make the Dia- 
 meter of an Inch ; wherefore in a cubic Inch 
 there will be a million of fuch Sands. And 
 as he found the Milt of the Cod-Fiih to be 
 about fifteen cubic Inches, it muft contain 
 fifteen Millions of Quantities as big as a 
 Grain of Sand. Now, if each of thefe Quan- 
 tities contains ten thoufand Animalcules, there 
 muft be in the whole one hundred and fifty 
 thoufand Millions. 
 
 Then, to find out, in a probable manner, 
 the Number of People living upon the whole 
 Earth at one Time ; he reckons, that in a 
 great Circle there are five thoufand four 
 hundred Dutch fquare Miles ; whence he cal- 
 culates the Surface of the Earth to contain 
 nine Millions, two hundred feventy fix Thou- 
 
 Jrc Nat. Tom. I. P. II. p. 9. 
 
 fand, 
 
156 Of the Animalcules 
 
 fand, two hundred and eighteen fuchfquarc 
 Miles: and fuppofing one Third of the 
 Whole, or three Millions, ninety twoThou- 
 iand and feventy two Miles to he dry Lanr 1 . 
 and of this, two Thirds, or two Millions, 
 fixty one Thoufand, three Hundred and 
 eighty two Miles to he inhabited; and fup- 
 pofing farther, that Holland and Weft-'Frief- 
 land are twenty -two Miles long and feven 
 broad, which make one Hundred and fifty 
 four fquare Miles ; the habitable Part of the 
 World is thirteen Thoufand, three Hundred 
 and eighty five times the Bignefs of Holland 
 and Weft-t'riejland. 
 
 Now, if the People in thefe two Provinces 
 be fuppofed a Million ; and if all the other 
 inhabited Parts of the World were as po- 
 pulous as thefe, (which is highly impro- 
 bable) there would be thirteen Thoufand, 
 three hundred and eighty five Millions of 
 People on the Face of the whole Earth : but 
 the Milt of thisCod-Filh contained one hun- 
 dred and fifty thoufand Millions of Animal- 
 cules ', which is ten tunes more than the 
 Number of all Mankind. 
 
 The Number of thefe Animalcules may be 
 computed another Way : for the ingenious 
 Author of Speclacle de la Nature fays *, that 
 
 * Vid. $pe8. de la Nat. Eng. !2mo Edit. Vol.1, p. 231. 
 
 three 
 
in Semine Mafculina 157 
 
 three curious People counted, with all the 
 Cure they were able, as ninny of the Eggs 
 or Row of a female Cod-Fifh a> weighed a 
 Dram, and agreed pretty well in the Num- 
 ber, which they wrote down. They then 
 weighed the whole Mais, and letting down 
 eight times the Sum of one Dram for every 
 Ounce, which contains eight Drams, all the 
 Sums together produced a Total of nine 
 Millions, three hundred and thirty four Thou- 
 fand Eggs. * 
 
 Now iuppo ling (as Mr. Leeuwenhoek 
 does of the Semen Mafculinum of Frogs) that 
 there are ten Thou land Animalcules in the 
 Milt for each One of the female Ova in the 
 Row, it will follow, that fince the female Row 
 is found to have nine Millions, three hundred 
 thirty four Thousand Eggs, the whole Milt 
 of the Male may be reckoned to contain 
 ninety three thoufand four hundred and 
 forty millions o 1 " Animalcules : which, tho" 
 greatly fhort of the full Calculation, is al- 
 most (even times as many as the whole hu- 
 man Species. 
 
 To find the comparative Size of thefe 
 Animalcules, Mr. Leeuwenhoek placed a 
 
 * Four Millions and ninety fixthoufind Fggs were com- 
 puted in the Row of a Crab* each of which received it.^Nou- 
 nfhment by a Rope from the Crmft Cod)-. Fid. Art. Nat. 
 Tom. I. P. II. p. 2<iq. 
 
 Hair 
 
1 5^ Of *^ e Animalcules 
 
 * Hair of his Head near them, which Hair 
 through his Micro] cope appear'd an Inch in 
 Breadth ; and he was fatisfied that at leaft 
 Sixty fuch Animalcules could eafily lye with- 
 in that Diameter -, whence, their Bodies be- 
 ing Spherical, it muft follow, that two hun- 
 dred and fixteen Thoufand of them are but 
 equal to a Globe whofe Diameter is no 
 more than the Breadth of fuch an Hair. 
 
 He obferved, that when the Water where- 
 with he had diluted the Semen of a Cod- 
 Fifli was exhaled, the little Bodies of the 
 Animalcules burft in Pieces, which did not 
 happen to thofe in the Semen of a Ram : 
 which he imputes to the greater Firmnefs 
 and Confiftency of the latter, as the Fleih 
 of a Land Animal is more compact than that 
 of a Fifh. He likewife takes Notice, that 
 the Tails of thofe in Fifties are fo extreamly 
 (lender, that he could never be certain of his 
 feeing the very Tips or Extremities of 
 them. 
 
 In the Milt of a Jack, at leaft -j- ten 
 Thoufand Animalcules were difcernable, in a 
 Quantity not bigger than a Grain of Sand, 
 exactly, in Appearance, like thofe of the Cod- 
 Fifth ; and upon putting % f° ur times as 
 much Water to it, they were perceived to 
 become ftronger and brifker, and to fwim 
 
 * Phil.Tranf. Numb. 270. f Arc. Nat. Tom. I. 
 
 Par. II. p. 2. \ Phil. Tranf. Numb . . 
 
 a 
 
 5 
 
' 
 
 in Semine Mafculino. 159 
 
 as if in Purfuit of Prey, with greater Ve- 
 locity ; tho* (being viewed in a Capillary 
 Tube) their whole Courfe was no longer 
 than the Diameter of a Hair. 
 
 If you would view the Animalcules in 
 the Milt or foft Row of Fifties, fqueeze out 
 a little of it, and putting the Quantity of 
 a Pin's Head upon a fingle Iiinglafs, dilute it 
 with Rain or River Water, till the little Crea- 
 tures have fufricient Room to fvvim about 
 freely, and (hew themfelves to advantage ; 
 which they can by no means do unlefs it 
 be made very thin. Or, after you have 
 mixed fome Water with it, apply it to the 
 Microfcope in one of your fmalleft capillary 
 Tubes; which Way Mr. Leeuwenhoek 
 informs us, he found the mod: ufeful for rhc 
 Examination of the Semen of different Crea- 
 tures. [N. B. * The Eggs in the Row, and 
 Animalcules in the Milt of Fillies of one 
 Year old, are as large as in thofe of the fame 
 Species of twenty Years old.] 
 
 Upon opening the Seminal Vejjels of a 
 Cock, fqueezing out a fmall Drop of the Se- 
 men, and viewing it with a Microfcope, Le- 
 gions of Animalcules appeared therein, fwim- 
 ming in Crowds together, and croiTing one 
 
 * Arc. Nat. Tom. IN. p 1 88. 
 
 another 
 
160 Of the Animalcules 
 
 another with as much Briiknefs and Vigour 
 as if the Cock had been but newly dead, tho' 
 it was killed the Day before : And by feve- 
 ral Trials on the Semen of other Cocks it has 
 been found, that the Animalcules therein 
 will live many Hours in a capillary Glafs 
 Tube. — To a flight Obferver they feem in 
 the Form of Eels ; but if the greateft Mag- 
 nifiers be ufed with due Attention, they will 
 
 be found fhaped as Fig. III. Plate XII. 
 
 Their Size is lb extreamly minute, that a 
 -j~ Million of them are fuppofed not to 
 exceed the Bignefs of a Grain of Sand, and 
 their Tails cannot be difcerned without much 
 Difficulty, being ten thoufand times more 
 (lender than the Hair of a Man's Hand. 
 
 A little of the Seminal Matter taken from 
 the TenMcle of a D02;, abounded with Ani- 
 malcules, % a Million whereof would hardly 
 equal a large Grain of Sand : and after fome 
 of this Matter had been kept feven Days 
 in a Glafs Tube, feveral of the Animalcules 
 remained alive and vigorous. [Their Form 
 is fhewn Fig. IV.] — The Te/licles of a 
 Hare, tho' four Days dead, were alfo exceed- 
 ingly full of Animalcules like thofe in Dogs, 
 fwimming in a clear Liquor, but without 
 Motion. 
 
 f Arc. Nat. Tom. II. Par. II. p. 369. 
 t Arc. Nat Tom I. Par. II. p. i6a 
 
 Killing 
 
in Semine Mafculino. I 6 1 
 
 Killing a Female Rabbet immediately af- 
 ter the Coitus, and opening the Uterus there- 
 of, innumerable Animalcules were found in 
 a fmall Drop, taken from the Mouth of the 
 Fallopian Tube where it opens into the Ma- 
 trix: but none were dilcerned in the Ute- 
 rus itfelf, or farther along the Tube. They 
 had long Tails, and for the mod Part * fix 
 tranfparent Globules appeared on the Body 
 of each, as in Fig. V. i : tho' fome had only 
 one Globule at the End of the Body, and 
 another in the Tail, as Fig. V r . 2. 
 
 Examining a Drop of Semen taken from 
 the Tefticles of a Ram, it abounded with 
 Animalcules in as great Numbers as the fe- 
 minal Matter of other Creatures ; but with 
 this extraordinary -J- Singularity, that Multi- 
 tudes of them fwam the fame Way together, 
 
 and 
 
 * Arc. Nat. Tom. I. Par. II. p. 160. 
 •f- Mr. Leeuw enhoek open'd the Uterus of an Ewe, 
 which about fever.tcen Days before had been coupled with 
 a Ram, and in one of the Cornea obferved a little reddijh 
 Jlejby Subjlancc wherein no Shape could be diilinguifhed. He 
 put this in a Glafs Tube the Thicknefs of a Quill, filTd with 
 Oy I cf Turpentine, and apply 'd it to his Mkrojcope, but could 
 make nothing of it in that Manner. Wherefore he took it 
 Jrom the Tube, and extending it very gently out of the round 
 Figure in which it lay, he perceived extreamly plain the 
 Formation of all the Vertebrae, with the Blood- Veffels and 
 Ramifications puffing over them, and in two Places could lee 
 the Spinal Marrow. He could alio diltinguifh not only the 
 Head, but alfo the Mouth, Brain, and Eyes the Bignefs of 
 two Grains of Sand, and clear as Cryftal : He faw hkewife 
 M the 
 
1 62 Of the Animalcules 
 
 and feemed to have the Inclination of Sheep, 
 to follow their Leader and move in Flocks. 
 Mr. Leeuwenhoek fays, he found fo 
 much Pleafure in obferving this, that he 
 called in fome Neighbours to mare it with 
 him. 
 
 Their Form was that of Fig. VI. 
 
 A Buck being killed in Rutting- time, the 
 J Vafa Defer entia were found turgid with a 
 milky Fluid, a Drop whereof, when applied 
 to the Microfcope, appeared full of Animal- 
 cules moving very brifkly. The greateft 
 Difficulty was to lay them properly before 
 the Mi cr of cope : for when the Matter is too- 
 thick, nothing can be feen but a confufed 
 Motion, and when fpread thin it dries away 
 immediately ; but by diluting it with warm 
 'Water, juft enough to change its Colour, 
 they were feen diftinctly. 
 
 The human Semen has likewife been view- 
 ed by the Micro/cope, and found no lels 
 
 the Ribs and Interlines : though the whole Creature was no- 
 larger than the eighth Part of a Pea. — /After this he open'd 
 the Uterus of another Ewe, but three Days from the Coitus ;- 
 and fearching the Liquor coming from it very diligently with 
 a Magnifying Glafs, obferved a little Particle the Size of a 
 Grain of Sand ; which, examining with an excellent Micro- 
 fc-pr, he with great Pleafure found to be an exceedingly mi- 
 nute Lamb lying round in its Integuments, and could 
 plainly difcern its Mouth and Eyes. Fid. Arc. Nat. Tom. I. 
 Par. II. pag. 165, & 173. 
 
 % Philoloph. Trar.f. Numb. 284. 
 
 plentifully 
 
in Semine Mafculino. 163 
 
 plentifully ftocked with Life than that of 
 other Animals : for more than ten thoufand 
 living Creatures were feen, by Mr. Lee u- 
 wenhoek, moving in no larger a Quantity 
 of the fluid Part thereof than the Bignefs of 
 a Grain of Sand j and in the thicker Part 
 they were fo throng'd together, that they 
 could not move for one another. Their Size 
 was fmaller than the red Globules of the 
 Blood, and even lefs than the millionth Part 
 of a Grain of -f- Sand. The Bodies of them 
 are roundiih, fomewhat flat before, but 
 ending (harp behind, with Tails exceedingly 
 tranfparent, five or fix times longer, and 
 about five times more ilender than their Bo- 
 dies. They move themfelves along by the 
 violent Agitation of their Tails, in various 
 Bendings, after the Manner that Eels or 
 Serpents lwim ; and, fometimes, their Tails 
 are moved thus eight or ten times in getting 
 forwards the Diameter of a Hair. 
 
 Their Shape and Form is fhewn Fig. VII. 
 
 It is wonderful to confider the Minutenefs 
 of thefe little Animals, and particularly the 
 amazing Slendernefs of their Tails : which 
 mull, nctwithftanding, be furniih'd with as 
 many Joints as the Tails of larger Creatures, 
 fince they are able to move them with great 
 Agility: and, befides, every one of thefe 
 
 f Arum. Nat. Tom. II. Par. II. p. 61, 69, 2S6. 
 
 M 2 Joints 
 
1 64 Of the Animalcules 
 
 Joints muft be provided with its proper Muf- 
 cles, Nerves, Arteries and Veins ; and alfo 
 with Fluids circulating thro' them, and 
 fupplying them with Nourishment, Strength, 
 and Motion. In fhort, the Mind lofes itfelf 
 in contemplating a Minutenefs beyond all 
 human Conception ; tho' Reafon tells us, it 
 certainly muft be. I remember, Dr. Power 
 has a fine Tallage to this Purpofe in the 
 Preface to his Experiments. " It has often 
 " feem'd to me (fays he) an ordinary Pro- 
 " bjbility, and fomething more than Fancy 
 <c (how paradoxical foever the Conjecture 
 " may feem) to think, that the leaft Bodies 
 " we arc able to fee with our naked Eyes, 
 " are but middle Proportionals, as it were, 
 " betwixt the Great eft and Smalleft Bodies 
 tf in Nature ; which two Extremes lye e- 
 " quaily beyond the Reach of human Sen- 
 
 Ki fation. For, as one fide they are but 
 
 <c narrow Souls, and not worthy the Name 
 <c of Pbilo/bphers, that think any Body can 
 c< be too great, or too vaft in its Dimenfi- 
 f ' ons : fo likewife are they as inapprehen- 
 4C iive, and of the fame Litter with the 
 <! former, that, on the other fide, think the 
 " Particles of Matter may be too little, or 
 cc that Nature is Hinted at an Atom, and 
 Ci mull have a Non ultra of her Subdivifi- 
 tc oris/' 
 
 As 
 
in Semine Mafculino. 1 65 
 
 As the Animalcules in the Semen Mafcuh- 
 mim of different Creatures are not much un- 
 like in Shape, it is alio obfervahle, that they 
 do not differ in * B gnefs according to the 
 Sizes of the Creatures they are taken from ; 
 but feem, in this Refpecl, analagous to the 
 Seeds of Trees and Plants, whofe Size hears 
 very little Proportion to the Bigncfs of the 
 Trees and Plants producing them. The 
 Seed of an Apple, for In fiance, is fome 
 thoufands of times fmaller than a Cocoa- 
 Nut, tho' the Trees they grow on have not 
 that Difproportion : And the Seeds of To- 
 bacco (whereof a thouland -f weigh not a- 
 bove a fingle Grain) are lefs beyond Com- 
 panion than many kinds of other Seeds whole 
 Plants are not near fo large as Tobacco is. 
 Hence it comes to pafs, that Animalcules 
 maybe dilcovered in the Semen of the fm.illelf 
 Birds, Quadrupeds and Fifhcs, nay, and eren 
 in In feels too. For Mr. L e e y w e n h o e e 
 allures us, he found a white Matter he had 
 fometimes fqueezed from the hinder Parts of 
 male J Spiders, about the bignels of a Grain 
 of Sand, to be indeed their Semen, bydifco- 
 vering therein prodigious Multitudes oi Ani~ 
 malculeSy which continued living above five 
 Hours, but were fo extremely minute, that 
 he fuppofes a thoufand Millions cf them 
 
 * A e. Neit. Tom. IV. pag. 30. -f- Dr. Power'^ F\pe- 
 rim. png. 30. % Phiiofoph. Tranfaft. Numb. z-q. 
 
 M 3 wouU 
 
1 66 Of the Animalcules 
 
 would not equal the Size of a Grain of Millet. 
 He found them likewife in the Semen of the 
 a Dormoufe, in b Oyilers, in c Silkworms, in 
 the d Labella minima or fmall Dragon-Fly, 
 in the common e Fly, in the male * Flea, iu 
 g Gnats, and in feveral other Infects : and, 
 without doubt, a curious Enquirer will be 
 able to difcover them in abundance of Sub- 
 jects yet unexamined ; for Nature is uniform 
 in all her Works, and there is good Reafon 
 to believe that they certainly exift in all the 
 animal Part of the Creation. 
 
 Amongft the many Species of. Animalcules 
 obferved in Waters and Infufions, there are 
 h none found refembling thofe in Scmijie: 
 but the Animalcules in the Semen of all Sorts 
 of Creatures hitherto examined have a com- 
 mon and general Likenefs to one another ; 
 with this Particularity, that they appear. in 
 continual Motion, without the leaft Reft or 
 Intermiffion, provided the Fluid be furHcient 
 for them to fwim about in. 
 
 Many People have imagined, that living 
 Creatures might alfo be found in the other 
 animal 'Juices : but after the ftrictefl and 
 moft careful Examination, it appears certain, 
 
 a Arc. Nat. Tom. I. Par. II. p. 27. b Ibid. Tom. II. 
 Pari. p. 144. c Ibid Par. II. p. 422. d Ibid. Tom. IV. 
 p. 19. e Ibid. flbid. p. 20. g Ibid. p. 22. h Ibid. 
 To.n. III. p. 294. 
 
 that 
 

 in the Teeth. 167 
 
 that nothing with the leaft Token of Life is 
 to be (iifcovered by the bed Glaifes, either in 
 the Blood, Spittle, Urine, Gall, Chyle, or 
 any of the Humours, except the Semen only. 
 
 CHAP. XVII. 
 
 Animalcules in the Teeth. 
 
 T Hough no Animalcules can be found in 
 in the Saliva or Spittle, great Numbers, 
 of different Kinds, may be difcovered in the 
 ■wbitijlj Matter flicking between the Teeth : 
 if it be picked out with a Pin or Needle, 
 xnixt with a little Rain Water and Spittle 
 without Bubbles, and applied before the 
 Microfcope. And fometimes they are fo in- 
 credibly numerous, and fo full of Motion, 
 that the whole Mafs appears alive. 
 
 * The largeft Sort ((hewn Plate XIII. 
 Fie;. I. N°. 1.) move along very fwiftly in 
 the Spittle or Water ; of thefe there are but 
 few. 
 
 The fecond Sort arc more numerous, and 
 have a Motion peculiar to themfclves, as re- 
 preiented N°. 2. 
 
 * ViJ. Arc. Nat. Tom. IV. p. 40. Again, Tom. IV 
 Epift. 75. p. 310. 
 
 M 4 Tfce 
 
1 68 Of Animalcules in the Teeth. 
 
 The third Sort are roundifh, and fo mi- 
 nute, that a Grain of coarfe Sand would 
 equal a Million of them in Bignefs: they 
 move fo fwiftly, and in fuch Multitudes, that 
 they feem like Swarms of Gnats or Flies, and 
 the exact Shape of them is not eafy to be 
 diftinguifhed. 
 
 Some or all of thefe three Kinds may be 
 found, pretty conftantly, in the Matter taken 
 from between the Teeth of Men, Women, 
 or Children ; efpecially from between the 
 Grinders, even though they warn their Teeth 
 continually, and clean them with thcutmoft 
 Care : but from the Teeth of People that are 
 more carelefs, the faid Matter affords ano- 
 ther Sort of Animalcules, in the Shape of 
 Eels or Worms, as pictured N°. 4. Thefe 
 move themfelves backwards, or forwards, 
 with great Bendings of the Body ; and force 
 their Way through the minuter Animalcules 
 every where around them, with the fame 
 Eafe as a large Butterfly would breakthrough 
 a fwarm of Gnats. There are likewife, in 
 this Matter from the Teeth, other Sorts of 
 Animalcules , whole Motions are fo extreme- 
 ly languid, that without long Attention they 
 cannot be diftinguillied to be alive. 
 
 Obfervation. They all dye if Vinegar be 
 applied to them ; whence it feems reafonable 
 to concjude, that warning the Teeth and 
 Gu-.ns with Vinegar may be a Means of pre- 
 ferving th:m from thefe minute Creatures. 
 
 C H A P. 
 
[169] 
 
 CHAP. XVIII, 
 
 Of the Itch. 
 
 / T~ A HE Microfcope has difcovered, what 
 -* without it could fcarce have been ima- 
 gined, that the Diftemper we call the Itch, 
 is owing; to little In feels under the Cuticula, 
 whofe continual Bitings caufe an ouzing of 
 Serum from the Cutis, and produce thole 
 Puflules or watry Bladders whereby this Dif- 
 €d(e is known. This was found out by 
 DoctorBoNON io,* who obferving that itchy 
 People frequently pull out of their fcabby Skin 
 little Bladders of Water, with the Point of a 
 Pin, and crack them on their Nails like 
 Fleas, he determined to examine what thefe 
 Bladders might really be. Wherefore pick- 
 ing out with a fine Needle a little Pultule 
 from a Place fcabbed over, and where there 
 was a fevere Itching, he fqueezed a thin 
 Matter from it, and perceived a very fmall 
 white Globule fcarcely difcernable, which, 
 applying to the Microfcope, he found to be 
 a very minute Animal, in Shape refemblinga 
 Tortoife, of a whitiih Colour, but darker on 
 the Back than elfe where, with fome long and 
 thick Hairs, i {Tiling from it, very nimble in 
 its Motion, having fix Legs, a (harp Head, 
 
 * Phil. IranfaH. Numb. 283. 
 
 and 
 
170 Of the Itch, 
 
 and two little Horns ; being in Shape as re- 
 prefented by the two Pictures. Fin\ II. a. b. 
 Plate XIII. 
 
 This Experiment was repeated on itchy 
 Perfonsof all Ages, Sexes and Complexions, 
 and at all Seafons of the Year, and he con- 
 ilantly found the fame Animalcules in moil 
 of the watry Puftulcs : and though by rea- 
 fori of their Minutenefs and Colour, (which 
 is the fame as the Skin) it is difficult to dif- 
 cern thefe Creatures on the Surface of the 
 Body, yet he fometimes faw them upon the 
 Joints of the Fingers in the little Furrows of 
 the Cuticula, where they firft begin to enter 
 with their fharp Head, gnawing and work- 
 ing in their Bodies, till they are got quite 
 under the Cuticula, where they burrow from 
 Place to Place, caufe a troublcfome and grie- 
 vous Itching, and force the infected Perfon to 
 fcratch, which only ferves to increafe the 
 Malady; for, by breaking the. little Puftules 
 and fome fmall Blood- VefTels, Scabs, crufty 
 Sores, and fuch like foul Symptoms enfue : 
 whilit thefe mifchievous Animalcules efcape 
 the Nails by their Minutenefs, and difperfe 
 themfelves the farther. 
 
 Frequently obferving thefe Animalcules^ 
 he perceived one of them drop a little oblong 
 white Egg, almoft tranfparent, from the 
 hinder Part of its Body : and afterwards he 
 faw many of the fame Sort of Eggs ; which 
 proves them generated like other Creatures 
 
 from 
 
'],,> !'.'- 
 
 
 J'/<r/<- Xffl 
 
 
 FA/j: /i 2.1L 
 
 /■ wjV 
 
 &?■ xir-fl -2.-2.i2. 
 
Of the Itch. lyt 
 
 from a Male and Female, though he was 
 never able to diftinguifh the Sex of any he 
 examined. 
 
 The Figure of the Egg is fhewn c. 
 
 We may hence account how this Diftenv 
 per comes to be fo very catching, iince thele 
 .Animalcules by fimple Contact can eafily 
 pais from one P e l fu n to another, having not 
 only a fwift Motion, but clinging to every 
 thing they touch, and crawling as well upon 
 the Surface of the Body as under the out- 
 ward Skin : and a few being once lodged, 
 they multiply apace by the Eggs they lay. 
 The Infection may alio be propagated in a 
 like manner by Sheets, Towels, Handker- 
 chiefs, or Gloves, ufed by itchy People ; 
 fince theie Animalcules may eafily be har- 
 boured in iuch things, and will live out of 
 the Body two or three Days. 
 
 The Difcovery of thefe Animalcules fhews 
 the Reafon likewife why this Dillemper is 
 never to be cured by internal Medicines : 
 but requires lixivial Waflies, Baths, or Oint- 
 ments, made up with Salts, Sulphurs, Vi- 
 triols, Mercury, Precipitate, Sublimate, or 
 ibch kinds of penetrating and corroding Re- 
 medies as can powerfully kill thuie Vermin 
 in the Skin. And if, fometimes, we find 
 the Difeafe returns upon us in a little while 
 after we fuppofed it quite cured by Unction, 
 it is no great Wonder •. fince, tho' the Oint- 
 ment 
 
172 Of Scales on 
 
 ment may deftroy all the living Animalcules, 
 it may not probably kill their Young Ones 
 in the Eggs laid in Nefts in the Skin; 
 which, coming to hatch, may renew the 
 Diftemper. For this Reafon, it is advifable 
 to continue the Anointing for fome Days, 
 even after the Cure feems perfected. 
 
 CHAP. XIX. 
 
 Of Scales on the Human Skin. 
 
 / Tp H E Cuticula, Scarf-Skin, or outward 
 ■** Covering of the Body, is remarkable 
 for its Scales and for its Pores. 
 
 Its Scales are a Difcovery of the Micro- 
 fcope -, for being fo minute that * two hun- 
 dred of them may be covered with a Grain 
 of Sand, they could never be difcerned by 
 the naked Eye. They are placed as on 
 Fifties, -j- three deep ; i. e. each Scale is fo 
 far cover'd by two others, that only a third 
 Part thereof appears : which lying over one 
 another, may be the Caufe why the Skin of 
 the Body appears % white 5 for about the 
 Mouth and Lips, where they only juft meet 
 together, and do not fold over, the Blood- 
 
 * Fid. Arc. Nat. Tom. I. Par. II. p. 208. Again, 
 Tom. IV. p. 46. -\ Ibid. p. 47. % lb. p. 51. 
 
 Veffels 
 
the Human Skin. 173 
 
 VelTels are feen through, and the Parts look 
 red. The perfpirable Matter is fuppofed to 
 ilTue between thefe Scales (which lye over 
 the Pores or excretory VelTels through which 
 the watry and oily Humours perfpire) and 
 may find Vent in an hundred Places round 
 the Edges of each Scale *: fo that if a Grain 
 of Sand can cover two hundred Scales, it 
 will be able to cover twenty thoufand Places 
 where Perfpiration may ilTue forth. 
 
 A Piece of Skin taken from between the 
 Fingers, from the Forehead, Neck, Arms, 
 or any other foft Part of the Body, which 
 is not hairy, ferves bell: to fhew the Scales ; 
 for where the Skin is callous, they are glew- 
 ed as it were together. 
 
 They are generally of five Sides, as in the 
 Picture, Fig. III. a. 
 
 Their Dilpofition on the Skin is fhewn 
 Fig. III. b. 
 
 If they are fcraped off with a Pen-knife, 
 put into a Drop of Water, and fo applied 
 to the Microfcope, they will be feen to good 
 Advantage. 
 
 * Arcan.Nat.Tom.IV. p. 48. 
 
[ m ] 
 
 C M A P. XX. 
 
 The Pores of the Skin. 
 
 Tf VE R Y Part of the human Skin is foil 
 *-' of excretory Duffs or Pores, which emit 
 fuperfluous Humours, continually, from the 
 Mafs of the circulating Fluid. 
 
 In order to view the Pores, cut a Slice of 
 the upper Skin with a fharp Razor as thin 
 as poffible: then immediately cut a fecond 
 Slice from the fame Place, which apply to 
 the Microfcopej and in a piece not larger 
 than a J Grain of Sand can cover, innumera- 
 ble Pores will be perceived, as plainly as little 
 Holes prick'd by a fine Needle may be 
 difcern'd if it be held up againft the Sun. 
 The Scales of the outer Skin prevent any 
 diftindt View of the Pores, unlefs they are 
 fcrap'd away with a Penknife, or cut off in 
 the above Manner j but if a piece of the 
 Skin between the Fingers, or in the Palms 
 of the Hands, be fo prepared, and then ex^ 
 amin'd, the Light will be feen very pleafant^ 
 ly through the Pores. 
 
 Mr. Leeuwenhoek endeavours to give 
 fome flight Notion of the incredible Num- 
 
 X Arcan. Nat. Tom. III. p. 409. 412, 
 
 ber 
 
The Pores of the Skin. 175 
 
 ber of Pores in a human Body. He -J- fup- 
 pofes there are one hundred and twenty fuch 
 Pores in a Line one tenth of an Inch long; 
 however, to keep within compafs, he reckons 
 only one hundred. An Inch in length will 
 then contain a thoufand in a Row, and a 
 Foot twelve thoufand. According to this 
 Computation, a Foot fquare muft have in* 
 it an hundred and forty four Millions : and 
 fuppofing the Superficies of a middle fized 
 Man to be fourteen Feet fquare, there will 
 be in his Skin two thoufand and fixteen 
 Millions of Pores. 
 
 To acquire fome clearer Idea (till of this 
 prodigious Number of Pores by our Con- 
 ception of Time ; let us reckon with * 
 Mersennus, that each Hour confifts of 
 fixty Minutes, and each Minute of fixty 
 Seconds, or fixty Pulfations of an Artery : 
 in one Hour there will then be three Thou- 
 fand and fix hundred Pulfes ; in twenty-four 
 Hours eighty-fix thoufand and four Hundred; 
 and in a Year thirty-one Millions five hun- 
 dred and thirty-fix Thoufand. But there 
 are about fixty-four times as many Pores 
 in the Surface of a Man's Skin, and there- 
 fore he muft live fixty-four Years, e'er he 
 will have had a Pulfation for every Pore in 
 his Skin. 
 
 f Arcan. Nat. Tom. III. p.413. 
 * Ibid. p. 413. 
 
 1 Dr. 
 
1 76 The Pores of the Skirt. 
 
 Dr. Nathaniel Grew obferves, that 
 the * Pores through which we perfpire are 
 more particularly remarkable in the Hands 
 and Feet ; for if the Hand be well warned 
 with Soap, and examined with but an indif- 
 ferent Glafs, in the Palm, or upon the Ends 
 and firft Joints of the Thumb and Fingers, 
 innumerable little Ridges parallel to each 
 other, of equal Bignefs and Diftance will be 
 found. Upon which Ridges the Pores may 
 be perceived by a very good Eye, lying in 
 Rows, even without a Glafs : but, viewed 
 through a good Glafs, every Pore feems like 
 a little Fountain, with the Sweat ftanding 
 therein as clear as Rock- Water ; and, if 
 wiped away, it will be found immediately 
 to fpring up again. 
 
 When we confider the Multitude of Ori- 
 fices all over the Skin, it is reafonable to 
 imagine, that minute Animals, as Fleas, 
 Lice, Gnats, &c. do not with their (lender 
 Instruments make new Perforations, but 
 rather thru ft or infinuate them into the Vef- 
 fels of the Skin, and fuck out the Blood or 
 what other Humour is their proper Aliment. 
 
 f Philofoph. Tranfaftions, Numb. 159. 
 
 CHAP, 
 
[ *77] 
 
 C II A P. XXI. 
 
 Of the Louse. 
 
 '"TpHE Loufe has (6 tranfparent a Shell 
 ■*- or Skin, that we are able to difcover 
 niore of what pafles within its Body, than 
 in moil other living Creatures ; which ren- 
 ders it a delightful Object for the Micro- 
 fcope. 
 
 It lias naturally three -J- Divifions, viz* 
 The Head, the Breaft, and the Belly or Tail- 
 part. In the Head appear two line black 
 
 Eyes, with a Horn that has five Joints, and 
 is furroundcd with Hairs, ftanding before 
 each Eye ; from the End of the Nofe or 
 Snout there is a pointed projecting Part, ferv- 
 ing for a Sheath or Cafe to a Sucker, or 
 Piercer, which the Creature thrufts into the 
 Skin, to draw out the Blood or Humours 
 it feeds on, as it has no Mouth that opens. 
 This Piercer or Sucker is judged to be * 
 feven hundred times ilendcrer than a Hair ; 
 is contained in another Cafe within the firlt, 
 and can be thru ft out or drawn in at Plca- 
 fure. 
 
 The Bread: is marked very prettily in the 
 Middle, the Skin thereof tranfparent, and 
 
 ■\Vide S\v ammerdah Hift. Gener. des Infedles. p. 17;. 
 * Vide Arc. Nat. Tom. II. p. 74. 
 
 N full 
 
178 Of the Loufe. 
 
 full of little Pits. From the under Part of 
 it proceed fix Legs, each having five Joints, 
 their Skin refembling Shagreen, except to- 
 wards the Ends, where it appears fmoother. 
 Each Leg terminates in two hooked Claws 
 of unequal Length and Size, which it ufes 
 as we would a Thumb and middle Finger. 
 There are -\ Hairs between thefe Claws r as 
 well as over all the Legs. 
 
 On the Back of the Tail-part we may dif- 
 cern fome * Ring-like Divifions, abundance 
 of Hairs, and a fort of Marks that look like 
 the Strokes of a Rod on one that has been 
 whipt. The Skin of the Belly feems like 
 Shagreen, and towards the lower End is 
 clear and full of little Pits ; at the Extre- 
 mity of the Tail are two little femicircular 
 Parts, covered all over with Hairs, which 
 ferve to conceal the Anus. 
 
 When the Loufe moves its Legs, the Mo- 
 tion of the Mufcles (which all unite in an 
 oblong dark Spot in the Middle of its Breaft) 
 may be diftinguifhed perfectly : and ib may 
 the Motion of the Mufcles in the Head 
 be, when it moves its Horns. The Motion 
 of the Mufcles is alfo viable in the feveral 
 Articulations of the Legs. We may like- 
 wife fee the various Ramifications of the 
 
 *|- WSWAMMERD. p. I75. 
 
 * Vide Phi.'ofoph. Tranf. Numb. 102. 
 
 Veins 
 
Of the Loufe. 179 
 
 Veins and Arteries (which are white) with 
 the Pulle regularly beating in the Arteries. 
 But the moft furprifing of all is the peristal- 
 tic Motion of the Inteftines, continued from 
 the Stomach along all the Guts down to the 
 Anus. 
 
 If a Loufe, when very hungry, be placed 
 on the Back of the Hand, it will thruft 
 its Sucker into the Skin, and the Blood may 
 be feen pafling in a fine Stream to the Fore- 
 Part of the Head ; where, failing into a 
 roundiih Cavity, it pafles again, in a like 
 Stream, to another circular Receptacle in the 
 Middle of the Head j from thence through 
 a 1 mailer Veffel to the Bread ; and then to 
 a Gut that reaches to the hinder Part of 
 the Body, where in a Curve it turns a little 
 
 upwards. In the Bread: and Gut the 
 
 Blood is without IntermiHion moved with 
 great Force, efpecially in the Gut, and that 
 with fuch a ftrong Propulfion downwards and 
 fueh a Contraction of the Gut as is amazing : 
 which continual and drons; Action of the 
 Stomach and Bowels upon the Food of this 
 Creature, to further its Digedion, is worthy 
 to be confider'd,— — In the upper Part of 
 the crooked afcending Gut jud mentioned, 
 the propelled Blood dands dill, and ieems 
 to undergo a Separation : iome of it be- 
 coming clear and waterifh, while certain 
 N 2 little 
 
180 Of the Loufe. 
 
 little black Particles pafs downwards to the 
 Anus -f. 
 
 If a Loufe be placed on its Back *, two 
 bloody darkifh Spots appear ; the larger in 
 the Middle of the Body, and the lefTer to- 
 wards the Tail. In the larger Spot a white 
 Film or Bladder contracts and dilates up- 
 wards and downwards from the Head to- 
 wards the Tail j the Pulle of which is fol- 
 lowed by a Pulfe of the dark bloody Spot, 
 in or over which the white Bladder feems to 
 lye. This Motion of Syilole and Diaftole, 
 is feen beft when the Loufe grows weak. 
 The white pulfing Bladder feems to be the 
 Heart, for on pricking it the Loufe inftant- 
 ly dies. In a large Loufe the Puliation may 
 be feen in the Back, but the white Film not 
 without turning the Belly upwards. The 
 lower darkifh Spot Dr. Harvey conjectur'd 
 to be the Excrements in the Guts. 
 
 Lice are not Hermaphrodites, as has er- 
 roneoufly been imagined, but Male and 
 Female. Mr. Leeuwenhoek difcover'd 
 that the Males have $ Stings in their Tails, 
 but the Females none : and fuppofes the 
 fmartinp- Pain they fometimes give arifes from 
 their Stinging, when made uneafy by Pref- 
 
 f ^V.Philofoph.Tranfaa. N°. 102 
 * Vide Dr. Power's Obferv. 9. 
 \ Arc, Nat. Tom. II. p. 77. 
 
 fure 
 
Of the Loufe. 1 3 r 
 
 lure or otherwife ; fince, if roughly handled, 
 they may be Teen to thruft out their Stings ; 
 and as he felt little Pain or Unealinefs from 
 the Sucker or Piercer, tho' feven or eight 
 were feeding on his Hand at once. The 
 Females lay Eggs or Nitts, whence young 
 Lice come forth, perfect in all their Mem- 
 bers, and undergo no farther Change but 
 an Increafe of Size. 
 
 Mr. Leeuwfnhof. k being defirous to 
 learn the Proportion and Time of their In- 
 creafe, put two '''Females into a black Stock- 
 ing, which he wore both Night and Day ; 
 and found that in fix Days one of them had 
 laid fifty Eggs, and upon diffecting it law as 
 many more in the Ovary ; whence he con- 
 cludes, that in twelve Days it would have 
 laid an hundred Eggs. Thefe Eggs hatch- 
 ing in fix Days (which he found to be their 
 natural Time) would probably produce fifty 
 Males and as many Females : and thefe Fe- 
 males coining to full Growth in eighteen 
 Days, might each of them be fuppofed, af- 
 ter twelve Days more, to lay alfo an hundred 
 Eggs; which Eggs in fix Days farther (the 
 Time required to hatch them) might pro- 
 duce a young Brood of five Thoufand-J-. 
 So that, in eight Weeks, a Loufe may fee 
 five thoufand of its own Defcendants ; an 
 
 * Ibid. p. 78. 
 
 |- Arcan, Nat. Tom. I. p. 78. 
 
 N 3 Increa/e 
 
]82 Of the Loufe. 
 
 Increafe hardly credible, were it not proved 
 by Experience. 
 
 A Loufe may be differed cafily in a fmall 
 Drop of Water, upon a Slip of Glals that 
 can be apply 'd to the Mlcrcjcope ; but with- 
 out Water the Parts are very difficult to di- 
 vide, and when ftparated lhrivel and dry up 
 immediately. Thus, rive or fix Eggs of a 
 full Size and ready to be laid may be found 
 in the Ovary of a Female, with fixty or 
 feventy of different Sizes, but all much more 
 minute, as the Eggs are in the Ovary of a 
 lien. In the Male the Penis is remarkable, 
 and alio the Teftes, whereof it has a 
 double Pair j the Sting likewife deferves a 
 curious 'Examination. Thefe Creatures avoid 
 the Light as much as poflible, and are im- 
 patient of Cold. The Females if farting 
 appear very white, and even after feeding 
 feem lefs red than the Males, the Blood not 
 appearing fo plainly through their Veflels, 
 from the Multitude of their Eggs. 
 
 The Picture of the common Loufe is given 
 Plate XIII. Fig. IV. 
 
 Its Piercer or Sucker is {hewn by a. 
 
 The Sting of the Male by b. 
 
 There's another Kind of Lci/je> found 
 about uncleanly People, which from its 
 Shape is called the Crab-Loufe. The Ver- 
 min adhering to and feeding on the Bo- 
 dies of different Animals, though much un- 
 2 like 
 
Of the Loufc. 183 
 
 like in Form and Size, are alfo commonly 
 called Lice. Of theie there are numberlefs 
 
 Species, feveral whereof we are obliged to 
 Seignior Rkdi for giving us the Draw- 
 ings of, at the End of his Treatife de Gene- 
 ratione Jnfccloriun, whence Mr. Albin 
 has taken them, into his Book of Spiders : but 
 few of thefe have been fumciently examined 
 by the Micro/cope, and there arc great Va- 
 rieties of other Kinds that are yet quite un- 
 known. 
 
 Even Infects are infefted with Vermin that 
 feed on them and torment them. A Sort of 
 Beetle known by the Name of the Loufy 
 Beetle, is remarkable for Numbers of little 
 Creatures that run about it nimbly from 
 Place to Place, but will not be fhaken off. 
 Some other Beetles have Lice alfo, but of 
 different Kinds. 
 
 The Earwig is troubled frequently with 
 minute Infects, efpecially juft under the fet- 
 ting on its Head. They are white and min- 
 ing like Mites, but much (mailer : they are 
 round-backed, flat-belly'd, and have long 
 Legs, particularly the two foremoH:. The fame 
 has not been obferved on any other Animal. 
 
 Snails of all Kinds, but chiefly the large 
 ones without Shells, have many little Infects, 
 extreamly nimble, that live and feed upon 
 them. 
 
 Numbers of little red Lice, with a very 
 
 final! Head, and in Shape refembling a Tor- 
 
 N 4 toifc, 
 
184 Of the Loufe. 
 
 toife, are often to be feen about the Legs of 
 Spiders. Wbilil the Spider lives they cling 
 clofely to it, but if it dies they leave it. 
 
 Whitifli Lice are frequently to be difco- 
 vered running very nimbly on Humble- Bees : 
 I have feen them frequently on Ants : many 
 Kinds are difcoverable on Fifhes jKircher 
 lays, he has found Lice on Fleas j and, pro- 
 bably, very few Creatures are free from them. 
 
 As fome may be defirous to know what 
 Kinds of Lice * Seignior Redi has ob- 
 ferved and given Drawings of, the following 
 Lift is inferted to iatisfy their Curiolity. 
 Lice found on the Hawk three Sorts : on 
 the large Pigeon, the Turtle- Dove, the Hen, 
 the Starling, the Crane. On the Moor- Hen 
 three Sorts. On the Magpye, the Heron, 
 the leiler Heron, theSwan, theTurkifh Duck, 
 the Sea-Mew, the fmaller Swan : on the 
 wild Goofe two Sorts: on the Teal, the 
 Kaftrel, the Peacock, the white Peacock, 
 the Capon, the Crow, the white Starling : on 
 Sweet-meats and Drugs : on Men, two Sorts, 
 viz. the common Loufe and the Crab- 
 Loufe : on the Goat, the Camel, the -f Afs, 
 the African Ram, the African Hen ; on the 
 Stag two Sorts, and on the J Tiger. 
 
 CHAP. 
 
 * Redi calls the Vermin on Beafts Fediculi or Lice, thofe 
 on Birds Puttees or Fleas. He fays every Kind of Bird has its 
 particular Sort of Fleas, different from thofe of other Birds : 
 That all when fiift hatch'd are white, but gradually acquire 
 a Colour like the Feathers they live among : yet remain 
 
 tranfpareni 
 
[ 1*5 ] 
 
 CHAP. XXII. 
 
 Of the Wood-Loufc. 
 
 'Tp < JIERE's a little Animal, in Shape and 
 ■^ Colour like a Loufe, that runs hviftlv 
 by Starts or Stops, and is commonly found 
 on the Leaves and Covers of Books, or a- 
 mongft rotten Wood: 'tis called a Wood- 
 Loufe or Wood-Mite \ and is known almolr 
 to every Body. The Eyes of this Creature 
 are of a golden Colour, and can be drawn in 
 or thrult out at Pleafure; the periitaltic 
 Motion of the Bowels appears in it diilincl- 
 ly, and what is (till more wonderful, a Mo- 
 tion of the Brain is feen. 
 
 I take this to be the Animal Mr. Deru am 
 calls the Pcdiculus pulfatorius or Death- 
 Watch, (in Phil. Tra?ijacl. Numb. 291.) 
 where he fays, the Pediculus Pulfatorius, 
 and the Scar abacus Jbnicephalus are the only 
 two Infects that make regular clicking Noifes 
 like the Beat of a Pocket Watch. 
 
 tranfparent enough for a good Micro/cope to difcover the Mo- 
 tions of their Intellines : That the Crane has a white Sort, 
 mark'd as it were with Arabic Characters : nnd that their 
 £ize is not proportioned to the Birds they breed upon, for the 
 little Black-bird has Fleas as large as the Snvan. 
 
 •f A r 1 s tot L e in his Hi/?o>y of Animals , and Pliny, on 
 his Authority, aflerts, that Jffit and Sb'ecp are free from Ver- 
 min : but Red 1 proves they are both miilaken r.s to the A is ; 
 and as to Sheep every Shepherd Eoy is able to confute them. 
 
 X The Loufe of the Lion refembles that of the Tige, in 
 Shape, but is larger, and of a brighter red. Vid.jk.BOi 
 Experim. circa Gener. InfeQ. pag. 31 z. &feq. 
 
 CHAR 
 
B 
 
 [ 186] 
 
 CHAP. XXIII. 
 
 Of Mi tes. 
 
 ;Y Mites are commonly underftood the 
 minute Creatures found in great Abun- 
 dance on Cheefe that is decaying. To the 
 naked Eye they appear like moving Par- 
 ticles of Dud ; but the Micro/cope difcovers 
 them to be Animals, perfect in all their 
 Members, having as regular a Figure, and 
 performing all the neceflary Offices of Life, 
 in as orderly a Manner, as Creatures that ex- 
 ceed them many Millions of times in Bulk. 
 
 They are cruftaceous * Animals, and 
 ufually tranfparent. The principal Parts of 
 them are, the Head, the Neck, and Body. 
 The Head is fmall in Proportion to the Body, 
 with a (harp Snout, and a Mouth that opens 
 and fhuts like a Mole's. They have two 
 little Eyes, and are extremely quick-lighted ; 
 for if you touch them once with a Pin or 
 other Inftrument, you'll perceive how rea- 
 dily they avoid a fecond Touch. Some have 
 fix Leg?, and others eight j which proves 
 them of different Sorts, tho' in every Refpedt 
 befides they appear alike. lEach Leg has fix 
 joints, furrounded with Hairs, and two little 
 
 * Vid. Power's Obferv. Hook's *Microgr p. 214. 
 
 Claws 
 
Of Mites. 187 
 
 Claws at the Extremity thereof, which can 
 eafily take up any Thing. The hinder Part 
 of the Body is plump and bulky, and ends in 
 an oval Form j with a few exceeding long Hairs 
 hTuing therefrom. Other Parts of the Body 
 and Head are alfo thinly befet with long 
 Hair?, 
 
 Thefe Creatures are Male and Female, 
 The Female lays Eggs j whence (as in Lice 
 and Spiders) the young ones iiTue forth with 
 all their Members perfect, though mod ex- 
 ceedingly minute: but, notwithstanding their 
 Shape does not alter, they call their Skins 
 feveral times before they attain their full 
 Growth. 
 
 They may be kept alive many Months 
 between two concave GlaiTes, and applied to 
 the Microfcope at Pleafure , and by often 
 looking at them many curious Particulars 
 will be difcovered. They may thus frequent- 
 ly be feen -J- in coitu y conjoined Tail to Tail ; 
 for though the Penis of the Male be in the 
 Middle of the Belly, it turns backwards like 
 that of the Rhinoceros. The Coitus is per- 
 formed with an incredibly fwift Motion. 
 Their Eggs, in warm Weather, hatch in 
 twelve or fourteen Days j but in Winter- 
 time and cold Weather not under feveral 
 
 f Vid. Arc Nat. Tom. IV. p. 360. 
 
 Weeks. 
 
3 83 Of Mites. 
 
 Weeks. 'Tis not uncommon to fee the 
 young Ones ftruggling to get clear of the 
 Egg-fhell, which fometimes they are a Day 
 about. 
 
 The Diameter of a Mite?, Egg feems equal 
 to the % Diameter of the Hair of a Man's 
 Head ; and fix hundred fuch Hairs are a- 
 bout equal to the Length of an Inch. Sup- 
 poiing, then, a Pigeons Egg is three quarters 
 of an Inch in Diameter : four hundred and 
 iifty Diameters of a Mites Egg are but equal 
 to the Diameter of the Egg of a Pigeon: 
 and, confequently, if their Figures be alike, 
 we muft conclude, that ninety one Millions, 
 an hundred and twenty Thoufand Eggs of a 
 Mite are not larger than one Pigeon\ Egg. 
 
 Mites are moft voracious Animals: for 
 they devour not only Cheele, but likewife all 
 Sorts of dryed Fifn or Flefh, dryed Fruits, 
 Grain of all Sorts, and almofr. every Thing 
 befide that has a certain Degree of Moifture 
 without being over wet : nay, they may often 
 be observed preying upon one another. In 
 eating they thruft one Jaw forewards and the 
 other backwards alternately, whereby they 
 appear to grind their Food ; and after they 
 have done feeding, they feem to munch and 
 chew the Cud. 
 
 \ Vid. Philofoph. Tranfa&ions, Numb. 333. & 284. 
 
 Thefe 
 
Of Mites. 189 
 
 Thefe are the Vermin that find a Way 
 into the Cabinets of the Curious, and eat up 
 their fine Butterflies and other choice Infecls, 
 leaving nothing in their ftead but Duit and 
 Ruins. The only Way of preventing this, 
 is, to keep the Drawers or Boxes continually 
 fupply'd with Cawpbire, whole hot and dry 
 Effluvia penetrate, lhrivel up, and deftroy 
 the tender Bodies of thefe little mifchievous 
 Plunderers. 
 
 It mull however be remembered, that 
 there are feveral Species of Mites, which 
 differ in fome Particulars, though their ge- 
 neral Figure and the Nature of them be the 
 lame. For Inftance, * the Mites in Malt- 
 Dud: and Oatmcal-Dufl are nimbler than 
 Cheefe-Mites^ and have more and longer 
 Hairs. The Mites among Figs refemble 
 Scarabs, have two Feelers at the Snout, and 
 two very long Horns over them, with three 
 Legs only on each Side, and are more flug- 
 gilh than thofe in Malt. Mr. Leejjwen- 
 hof. k obferved fome Mites on Figs to have 
 longer Flairs than he had feen on any other 
 Sorts ; and upon Examination found thofe 
 Hairs were fpicated, or had other little Hairs 
 uTuing from their Sides : whence he ima- 
 gin'd they might be jointed at the little Dis- 
 tances where thefe Hairs came forth. He 
 
 Yid Power's Obfcrv. p. 20. 
 
 had 
 
j go Of Mites. 
 
 had alfo feen the like Hairs on other Miies, 
 tho' very feldom. Mr. Hook delcribes a 
 Sort of thefe Animals, which he terms -f 
 <wandri7ig Mites, as being to be found in 
 every Place almoft where they can get Food. 
 Happening, fome Years ago, to look into 
 an empty white Gallipot, I fancy 'd it was 
 dully ; but, on a nearer View, perceiving 
 the Particles to move, I examin'd them by 
 the Microfcope^ and difcovered what I had 
 taken for Duft to be Swarms of thefe wan- 
 dring Mites, which were tempted and brought 
 thither by the Smell of fome Caviere, that 
 had been in the Gallipot a few Days before* 
 
 The Mite is exceedingly tenacious of Life; 
 I have kept them in my Glafles Months to- 
 gether, even without Food j and Mr. Leeu- 
 wenhoek fays, one he ftuck upon a Pin 
 before his Micro/cope $ lived in that Condi- 
 tion eleven Weeks. 
 
 The Picture of the Mite is fhewn Plate 
 XIII. Fig. V. 
 
 One of its Eggs appears jufl by, at a. 
 
 •f Hook's Microgr. p. 205. 
 
 % Vid. Arc. Nat. Tom. IV. p. 363. 
 
 CHAP. 
 
[ i9i ] 
 
 CHAP. XXIV. 
 
 Of the Flea. 
 
 THIS well-known little Creature is co- 
 vered all over with black hard fhelly 
 Scales. Plates, or Divifions, curioufly jointed, 
 and foiled over one another, in iuch a Man- 
 ner, as to comply with all the nimble Mo- 
 tions and Activity of the Animal. The Scales 
 are curioufly polifhed, and befet about the 
 Edges with long Spikes, in the mod beauti- 
 ful and regular Order poflible. It's Neck is 
 finely arch'd, and much refembles the Form 
 of a Lobfter's Tail. The Head is very ex- 
 traordinary ; for from the Snout-Part there- 
 of proceed its two Fore-Legs, and between 
 them lies the Piercer or Sucker wherewith it 
 penetrates the Skin of other living Creatures, 
 and draws out its Food. It has two large 
 beautiful black Eyes, and a Pair of little 
 Horns or Feelers. Four other Legs are join'd 
 on at the Bread, fo that it has fix in all ; 
 which, when it leaps, fold fhort one with- 
 in another, and exerting their Spring all at 
 the fame Inflant, carry the Creature to a fur- 
 prifmg Diftance. 1 he Legs have many 
 Joints, are very hairy, and terminate in two 
 long iharp hooked Claws, as may be feen 
 Fig. VI. Plate XIII. 
 
 The 
 
igi Of the Flea. 
 
 The Fleas Piercer or Sucker is lodged be- 
 tween its Fore-Legs, and includes a Couple 
 of Darts or Lancets, which, after the Piercer 
 has made an * Entrance, are probably thruft 
 farther into the Flefh, to make the Blood 
 flow from the adjacent Parts, that it may be 
 fucked up j and feems to occaiion that round 
 red Spot, with a Hole in the Centre of it, 
 which we commonly call a Flea-Bite. This 
 Piercer, its Sheath opening fideways, and 
 the two Lancets within it are very difficult to 
 be feen, % unlefs the two Fore-Legs, be- 
 tween which they ufually are folded in and 
 concealed from View, be cut off clofe to the 
 Head : for a Flea rarely puts out its Piercer 
 except at the Time of feeding, but on the 
 contrary keeps it clofely folded inwards : the 
 befr Way therefore of coming at it is, by 
 cutting the Head offm-ft, and then the Fore- 
 Legs ; iince, in the Agonies of Death, it may 
 eafily be managed, and brought before the 
 Micro/cope. 
 
 Fleas are Male and Female, and lay Eggs 
 as well as Lice and Mites ; but are extream- 
 ly different in all the Progrefs of their Lives 
 befides, pafTing through the fame Changes ex- 
 actly as the Silkworm does. They depofite their 
 Eggs at the Roots of the Hair of Cats, Dogs, 
 
 * Vid. Arc. Nat. detect. Tom. IV. p. 22. 
 % Ibid. p. 332. Phil. Tranfaft. Numb. 249. 
 
 2 and 
 
Of the Flea. J 93 
 
 and other Animals, ilicking them faft there- 
 to by a kind of glutinous Moifture. When 
 the Eggs hatch, not perfect Fleas, but little 
 Worms or Maggots, whofe Bodies have fe- 
 veral annular Diviiions thinly cover'd with 
 long Hairs, come out of them, and feed on 
 the Juices of the Body, whereto they clofe- 
 ly adhere *. Thefe Maggots are very brifk 
 and nimble, but if touch'd, or under any 
 Fear, roll themfelves up on a fudden in a 
 round Figure, and continue motionlefs for 
 fome Time ; after which they {lowly open 
 themfelves, and crawl away, as Caterpillars 
 do, with a lively and fwift Motion. 
 
 When the Time of their Change ap- 
 proaches, they conceal themfelves as much 
 as polTible ; eat nothing, lie quiet, and feem 
 as if dying : but if viewed with the Micro- 
 /cope, will be found, with the Silk or Web 
 that comes out of their Mouth, weaving a 
 Covering or Bag round them, whole Infide 
 is as white as Paper, though without it al- 
 ways appears foil'd with Dirt. In this Bag 
 they put on the Chry falls or Aurelia Form, 
 and become Milk-white : but two or three 
 Days before they break from this Prifon, 
 their Culour darkens, they acquire Firm- 
 nefs and Strength, and as foon as they illue 
 from the Bag are perjeel Fleas , and able to 
 leap away. 
 
 * Phil. Tianfad. Numb. 249. 
 
 O It 
 
194 Of the Flea. 
 
 It has been difcovered, by putting the 
 Eggs of Fleas in a fmall Glafs Tube, and 
 keeping it conftantly warm in one's Bofom, 
 that, in the Midft of Summer, they hatch 
 in four Days: then, feeding the Maggots 
 with dead Flies, which they fuck greedily, 
 in eleven Days they come to the full Perfec- 
 tion of their reptile State : when the Maggot 
 fpins its Bag, and in four Days more changes 
 into a Chryfalis; after lying in which Con- 
 dition nine Days, it becomes a perfecl Flea. 
 It is then immediately capable of Coition, 
 and in three or four Days lays Eggs. So 
 that in * twenty- eight Days a Flea may 
 come from the Egg itfelf, and propagate its 
 Kind j and their vail Increafe will not feem 
 fo great a Wonder, if we confider, that 
 from March to November there maybe i^st^v 
 or eight Generations of them. After having 
 laid their Eggs they foon die, as all Creatures 
 do that undergo fuch like Changes. 
 
 By keeping Fleas in a Glafs Tube corked 
 at both Ends, but fo as to admit frefh Air, 
 their feveral Actions may be obferved, and 
 particularly their Way of coupling, which is 
 performed Tail to Tail, the Female (which 
 is much the larger) Handing over the Male. 
 They will alfo be feen to lay their Eggs, not 
 all at once, but ten or twelve in a Day for 
 
 * Vid. Arc. Nat. Tom. IV. p. 325. 
 
 feveral 
 
Of the Flea. 195 
 
 feveral Days fuccemvely j which Eggs hatch 
 in the fame Order. 
 
 A DiffecYion of the Flea may be effected 
 after the fame Method as that of the LouJe y 
 that is, in Water ; the * Stomach and 
 Bowels, with their periitaltic Motion may 
 plainly be diftinguiihed, and alio the -f Teltes 
 and Penis, together with Veins and Arteries 
 minute beyond Conception. Le eu wen- 
 hoe k affirms, that he has likewife difcover'd 
 innumerable Animalcules fhaped like Ser- 
 pents in the Semen mafculinum of a Flea. 
 
 Two Things in this Creature deierve our 
 Confideration, to wit, its furprizing Agility, 
 and its prodigious Strength, whereby it is 
 enabled to leap above an hundred times its 
 own Length : as has been proved by Expe- 
 riments. What vigorous Mufcles ! what a 
 Springinefs of Fibres mult here be! and how 
 weak and fluggim, in Proportion to its own 
 Bulk, is the Horfe, the Camel, or the Ele- 
 phant, if compared with this puny Infect ! 
 
 A Flea's Egg is (hewn Plate XIII. Fig. 
 VI. 1. 
 
 The Worm or Maggot proceeding from it 
 Fig. VI. 2. 
 
 * Vii. Arc. Nat. Tom IV. p 20. 
 f Again, pag. 335. 
 
 O 2 CHAP. 
 
[ i 9 6 ] 
 CHAP. XXV. 
 
 (^SPIDERS. 
 
 pVERY Body is Co well acquainted with 
 **-' the general Form of a Spider^ even 
 without the Afliftance of a Micro] cope, that 
 I mail fpend no Time in the Description of 
 it : but proceed to give an Account of fome 
 Particulars in this Animal, which are difco- 
 verable only by that Inftrument. 
 
 As a Fly (the Spiders natural Prey) is 
 extreamly cautious and nimble, and comes 
 ufually from above, it was necerlary the 
 Spider mould be furnifhed with a quick 
 Sight, and an Ability of looking upwards, 
 forwards, and fideways at the fame time : 
 and the Micro/cope mews, that the Num- 
 ber, Structure, and Difpofition of its Eyes 
 are wonderfully adapted to ferve all thefe 
 Purpofes. 
 
 Moll: Spiders have eight * Eyes : two on 
 the top of the Head or Body (for there is 
 no Divifion between them, a Spider having 
 no Neck) that look directly upwards ; two 
 others in Front, a little below thefe, to dis- 
 cover all that paries forwards : and on each 
 fide a couple more, one whereof points fide- 
 
 * N. B. Spiders Eyes are not pearled. 
 
 2 ways 
 
Of Spiders. 197 
 
 ways forward, and the other fide ways back- 
 ward : fo that it can fee almoft quite round 
 it. All Kinds of them have not indeed a 
 like Number of Eyes, for we find ten in 
 fome, in others only eight, fix, or four; and in 
 the Field, Long- Legs, or Shepherd-Spider, no 
 more than two. But whatever the Number 
 be, they are immoveable, and tranfparent : 
 are fituated in a moft curious Manner, and 
 deferve the rlric"teft Examination. The heft 
 Way of viewing them is, to cut off the Legs 
 and Tail, and bring only the Head-part be- 
 fore the Micro/cope. 
 
 All Spiders have eight Legs, which they 
 employ in walking, and two Arms or fhort- 
 er Leg;s near the Mouth, that aft 1 ft in taking 
 their Prey. They appear thickly befet with 
 Hairs, have each fix Joints, and end w h 
 two hooked Claws, fcrrated, or havingTe h 
 like a Saw on their In fide, whereby they 
 cling raft to any thing j and at a little Dif- 
 ftance from thefe Claws a fort of Spur Hands 
 out, without any Teeth at all. See Fig. VII, 
 Plate XIII. 
 
 But the dreadful Weapons wherewith the 
 Spider feizes and kills its Prey are a Pair of 
 fharp crooked Claws or Forceps, (by fome, 
 tho' very improperly, called Stings) in the 
 Fore-part of its Head. The Scolopendra, 
 or Indian Millepedes, and feveral other In- 
 fe&s have Weapons of the like Form, and 
 O 3 ferving 
 
ioS Of Spiders. 
 
 ferving to the fame Purpofe. Thefe Claws 
 or Pincers ftand horizontally; and are, when 
 not made ufe of, concealed in two Cafes 
 contrived for their Reception : into which 
 they fold like a Clafp-knife, and there lye 
 between two Rows of Teeth, that are like- 
 wife employ'ft to hold fail its Prey. This 
 Apparatus is better (hewn than defcribed ; 
 See Fig. VIII. 
 
 Mr. Leeuwenhoek informs us, -f that 
 each of thefe Claws or Pincers has a fmall 
 Aperture or Slit near its Point, as in a Viper's 
 Tooth : through which he fuppofes a poi- 
 fonous Juice is injected into the Wound it 
 makes, occasioning Death to Flies and other 
 Infects. But Dr. Mead, in his mo ft excellent 
 Effay on Poifons, believes this to be a great 
 Miftake ; having not been able to difcern any 
 Exit or Opening, though he viewed thefe 
 Parts feveral times with a very good Micro- 
 fcope. And he w?s the more confirmed in 
 this Opinion, by examining a Claw of the 
 great Jlmerican Spider, defcribed by Pi s o, 
 and called Nhamdu, given him by Mr. Pe- 
 TIver : which being above fifty times big- 
 ger than that of any European Spider, if 
 there had been any Slit in it, he doubted 
 not his Glafs would have difcover'd it ; but 
 yet he found it to be quite folid. Befides, 
 
 f Vid. Arc. Nat. Tom. II. Part II. p. 319. 
 
 2 " after 
 
Of Spiders. 199 
 
 ff after repeated Trials he plainly faw that 
 
 " nothing drop'd out at the Claws> which 
 
 " were always dry, while the Spider bit, but 
 
 " that a (hort white Probofcis «ras at the fame 
 
 " time thruit out of the Mouth, which inftiil- 
 
 <{ ed a Liquor into the Wo. ind." And he 
 farther obferves, "that the Quantity of Li- 
 
 " quor emitted by our common Spiders w 
 
 " they kill their Prey, is viiibly to great, 
 
 " and the wounding Weapons io m: nitc, 
 
 lt that they could contain but a very incon- 
 
 " fiderable Portion thereof, if it were to be 
 
 " diicharged that way." 
 
 Spiders frequently caft their Skins, w r hich 
 maybe found in Cobwebs, perfectly dry and 
 tranfparent ; and from ilich Skins the For- 
 ceps or Claws (for they are always filed with 
 the Skin) may eafier be feparated, and exa- 
 min'd with more Exactnefs than in a living 
 Spider : for they commonly appear fpread 
 out fairly to view, and, by their Transpa- 
 rency every minute Part is iccn with much 
 Diftindtncfs. But neither this Way, nor 
 any other, have I been ever able to difcern 
 the Aperture Mr. Leeuwenhoek fpeaks 
 of. 
 
 The Contexture of the Webs of Spiders, 
 and their Manner of Weaving them, are far- 
 ther Difcoveries of the Micro/cope -, for that 
 informs us, that the Spider has live little 
 O 4 Teats 
 
200 Of Spiders. 
 
 Teats or Nipples near the Extremity of the 
 Tail, whence a gummy Liquor proceeds, 
 which adheres to any thing it is prefTed a-' 
 gainft, and being drawn out, hardens in- 
 iiantly in die Air, and becomes a String or 
 Thread, ftrong enough to bear five or fix 
 times the Weight of the Spider 's Body. This 
 Thread is compofed of feveral finer ones that 
 are drawn out feparatelv, but unite together 
 two or three Hairs Breadth dirt-ant from the 
 Body of the Spider. The Threads are finer 
 or coarfer according to the Bignefs of the 
 Spider that fpins them. Mr. Leeuwen- 
 hoek computes, that an hundred of the 
 fineil: Threads of a full-grown Spider are not 
 equal to the Diameter of the Hair of his 
 Beard ; and, confequently, if the Threads 
 and the Flair be round, ten thoufand fuch 
 Threads are not bigger than fuch an Hair. 
 He calculates' farther, that when young Spi- 
 ders firft begin to fpin, four hundred of 
 them are not larger than One that is full 
 grown; and, therefore, the Thread of fuch 
 a little Spider is fmaller by four hundred 
 times than the Thread of a full-grown One : 
 allowing which, four Millions of a young 
 Spider s Threads are not fo big as the fingle 
 Hair of a Man's Beard *. 
 
 Fid. Phil. Tranf. Numb. 272. 
 
 The 
 
Of Spiders. 2.01 
 
 The Eggs of fome Spiders are very pleafant 
 Objects, being round at one End and rlattifh 
 at the other, with a Depretfion in the Center 
 of the flattilh End, and a yellowiih Circle 
 round it. Their Colour is a blewiih White 
 like counterfeited Pearl ; and when they 
 hatch, the little Spiders come out perfectly 
 formed, and run about very nimbly. The 
 Female depofits her Eggs, to the Number 
 of five or fix hundred, in a Bag ltrongly 
 compofed of her own Web, which fhe ei- 
 ther carries under her Belly and guards with 
 the greateft Care, or elfe hides in fome lafe 
 Recefs. As foon as the Eggs are hatch'd, 
 the minute Spiders appear very agreeable in 
 the Micro/cope. 
 
 It has been before obferved, that the Cur- 
 rent of the Blood may be feen in the Legs 
 and Body of this Creature ; and the judicious 
 Obferver will difcover many other Wonders 
 in the Direction and Examination of its fe- 
 veral Parts, which it would be tireiome for 
 me to dwell on here. I cannot, however, 
 conclude this Head, without pointing out 
 two or three Kinds of Spiders as particularly 
 worth Notice. 
 
 There is a little white Field Spider with 
 fhort Legs, found plentifully among new 
 Hay, whofe Body appears like white Am- 
 ber, with black Knobs, out of each where- 
 of 
 
202 Of Spiders. 
 
 of grow Prickles like Whin- Pricks. Some 
 have fix, fome eight Eyes, that may be dis- 
 tinctly feen, quick and lively : each Eye has 
 a Violet-blew Pupil, clear and admirable, 
 furrounded by a pale yellow Circle *. 
 
 The wandring or -J- hunting Spider, who 
 fpins no Web, but runs and leaps by Fits, 
 has two Tufts of Feathers fixt to its fore 
 Paws, which well deferve being placed be- 
 fore the Micro/cope : the Variety and Beauty 
 of Colouring all over this little Creature af- 
 ford likewife a moft delightful View. 
 
 % The Long-Legs, Field, or Shepherd- 
 Spider is a molt wonderful Creature : It has 
 two Fore-Claws at a great Diftance from 
 the Head, tip'd with black like a Crab's, 
 that open and {hut in the Manner of a Scor- 
 pion's, and are Saw-like, or indented, on 
 
 the Infide. Cut all the Legs from this 
 
 Spider, and place it before the Micro/cope, 
 and you'll difcover, that the Protuberance 
 on the top of the Back is furniuYd with two 
 fine Jet-black Eyes. 
 
 The little red Spider that creeps on the 
 Barks of Trees mould alfo not be neglect- 
 ed. 
 
 * Dr. Pow er's Micro/cop. Olferv. p. 13. 
 + Hook's Microer. pag. 200. ± Ibid. 14. 
 
 CHAP. 
 
[ 2o 3 ] 
 
 C II A P. XXVI. 
 Of the Gnat. 
 
 ' J 1 H E Production of this Creature is from 
 JL an Eggi depofited by its Parent upon 
 the Waters, which firft becomes a Worm or 
 Maggot, then a very odd aquatic Animal, 
 (deicribed pag. 88.) and afterwards ixGnat. 
 The particular Beauties of it cannot potli- 
 bly be difcover'd without a Microfcope •, but 
 by the Affiftancc of that Inftrument, it ap- 
 pears to be adorned by Nature in a more ex- 
 traordinary Manner than moil other living 
 Creatures are. Its Tail-part is covered over 
 with Feathers, moft exquifitely difpofed in 
 Rows: of different Colours, but yet perfect- 
 ly tranfparent. The * Bread: (which is cruf- 
 faceous) is bedeck'd with little ftift Hairs 
 or Briftles, inilcad of Feathers ; and from 
 thence fix hairy Legs proceed, with fix Joints 
 to each, and at the End two little Claws. 
 The Feet are all over feather'd in a Manner 
 refembling the Scales of Fiflies, with abun- 
 dance of little black Hairs amongft them 
 appearing ftubborn like Hogs Briflles. Its 
 Wings are encompafled with a Furbelow of 
 long Feathers : and the Veins or Ribs that 
 
 * Swammerd. Hift. general, des Infeft. p. 108. 
 
 (ervc 
 
204 Of the Gnat, 
 
 ferve to ftrengthen them are alfo either fea- 
 thered or fcaled. Between thefe Ribs an ex- 
 ceeding thin tranfparent Membrane is ex- 
 tended, full of little black fharp pointed 
 Hairs, that are ranged every where with the 
 utmoft Regularity. But as there are -f diffe- 
 rent Sorts of Gnats, their Wings are alfo 
 very different, fome having a Border of long 
 Feathers, others of fhort ones, and others 
 none at all : the Rib-work of the Wings, 
 likewife, in fome is feather'd, in fome fcaled, 
 and in fome befet with Prickles. 
 
 But the moft wonderful Part of this Crea- 
 ture is its Head : as it contains the Horns, 
 the Sting or Sucker, and the Eyes. The 
 Horns of the brufh-horii d or Male Gnat are 
 a moft charming Object : it has two Pair, 
 one whereof is furrounded, at little Diftances, 
 with long Hairs, iffuing out circularly : each 
 Circle leffening more than other as it ftands 
 near the Extremity of the Horns : and the 
 whole together exactly reprefenting the Fi- 
 gure of the Plant called Equifetum or Horfe- 
 TaiL The other Pair are longer and much 
 thicker than the foregoing, and hairy from 
 End to End. In the great belly' 'd or Female 
 Qnat, the firft Pair of Horns, though of the 
 
 f Mr. Derham obferved near forty different Species of 
 Gnats about the Place where he lived,, which was Upminfter , 
 jn EJfex. Vid. PhsfiM-fbcolpg. p. 378. 
 
 fame 
 
Of the Gnat. 205 
 
 fame Figure as the Male's, has Hairs not 
 near fo long, and the fecond Pair is (horter 
 than the firft by at lcaft three Parts in four. 
 
 The Piercer, Sting, or Sucker is a Cafe 
 covered with long Scales, that lies concealed 
 under the * Gnafs Throat when not made 
 Ufa of. The Side onens, and four Darts are 
 thruft out thence, occafionally ; one where- 
 of, (minute as it is) ferves for a Sheath to 
 the other three. The Sides of them are ex- 
 treamly (harp, and they are barbed or in- 
 dented towards the Point, whofe Finenefs is 
 inexprefiible, and fcarcely to be difcerned by 
 the greateft Magnifier. When thefe Dans 
 are thruft into the FleiTi of Animals, either 
 fuccefiively, or in Conjunction, the Blood 
 and Humours of the adjacent Parts muft 
 flow to and caufe a Tumour about the 
 Wound, whofe little Orifice being clofed up 
 by the Compreilion of the external Air, can 
 afford them no Outlet. When a Gnat finds 
 any tender juicy Fruits, or Liquors, (he fucks 
 up what (he likes, through the outer Cafe, 
 without ufing the Darts at all : but if it is 
 Fled), that refills her Efforts, (he flings very 
 feverely, then (heaths her Weapons in their 
 Scabbard, and through them fucks up the 
 Juices the finds there. The Pain they caufe 
 
 * Vid. Hill, of Nat. Eng. \z Q . Edit. Vol. I. p. 124. 
 
 is 
 
2o6 Of the Gnat. 
 
 is only while they are entering, and conti- 
 nues not when the Gnat is lucking: nor is 
 its Stinging out of Revenge, but from mere 
 Neceihty, to obtain a proper Suftenance. 
 
 The Gnat's four Darts are fhewn Plate 
 XIII. Fig. IX. a. b. c. d. 
 
 A Gnat's Eyes, which form the greatefl 
 Part of its Head, are pearled, or compofed 
 of many Rows of little femicircular Protu- 
 berances ranged with the utmoft Exactitude. 
 What thefe Protuberances are, and the Pur- 
 pofes whereto they ferve, will be explained 
 when we come to treat of the Eyes of 2/z- 
 Jetls. 
 
 The Motion of the Inteftines may be feen 
 in the tranfparent Parts of this Animal, and 
 upon Diffeclion many curious Difcoveries 
 may be made. Mr. Leeuwenhoek fays, 
 he found in the * Semen of the Male num- 
 berlefs Animalcules fmaller than thofe in 
 Fleas, and in the Female a furprizing Quan- 
 tity of Eggs. And, indeed, the Spawn of 
 this Infect is amazingly great, in proportion 
 to its Size, being feen floating on the Waters 
 (though always fattened to fomething to pre- 
 vent its fwimming away) fometimes above 
 an Inch in Length, and half a quarter in Dia- 
 meter ; the Eggs (each of which has a little 
 
 * Leeuwenh. Arcea, Nat. Tom. IV. p. 22. 
 
 black 
 
Of the Ox-Fly, or Cad- Bee. 207 
 black Speck) being placed in exact Order, 
 and kept together by a Sort of Gelly or glewy 
 Matter, which the minute Maggots, when 
 hatched, carry down with them to the Bot- 
 tom, and thereby cement together the imall 
 Particles of Earth or Sand that form their 
 Cells or Cafes. 
 
 CHAP. XXVII. 
 Of the Ox-Fly, or Gad-Bee. 
 
 ANOTHER Creature that undergoes a 
 **> like Change, is the Ox-Fly, Dun-Fly, 
 
 or Gad-Bee, an Infect very troublefome to 
 Cows and Horfes. 
 
 This, like the Gnat, has a long Probofcis, 
 with a fharp Dart or Darts fheathed therein. 
 The Ufe of thefe Darts is to penetrate the 
 Fleili of Animals and feed on their Blood : 
 whereas the Probofcis can only ferve to fuck 
 the Juices, Honies, or Dews, from Fruits, 
 Flowers, or the Leaves of Plants : and Pro- 
 vidence feems to have kindly furnifhed it 
 with this twofold Inftrument, that if one 
 Sort of Provifion fails, it may be able to fub- 
 fift on the other. It is worth Enquiry whe- 
 ther Lice, Fleas, Houfe-Bugs, &c. are not 
 alfo provided for the lame Purpofes. 
 
 The 
 
2o8 Of the Ox-Fly, or Gad-Bee. 
 
 The Eggs of this Infect are depoiited in 
 the Waters, and produce an extraordinary 
 Kind of little Worm or Maggot, the Extre- 
 mity of whole Tail is incircled with move- 
 able Hairs, which, being expanded on the 
 Surface of the Water, enable it to float along, 
 * as in Plate VII. Fie. XIII. a. When it 
 would defcend towards the Bottom, thefe 
 Hairs are made to approach each other in an 
 oval Form, and indole a little Bubble of Air; 
 by means whereof it is able to rife again : and 
 if this Bubble efcapes, as fometimes it will, 
 the Infect immediately fqueezes out of its 
 own Body another like Bubble to fupply the 
 Place thereof. The Maggot, as defcending, 
 is fhewn, Fig. XIII. b. Its Snout has three 
 Divifions, whence three little pointed Bodies 
 are thruft out, in continual Motion, like the 
 Tongues of Serpents. 
 
 Thefe Maggots are frequently to be met 
 with in Water taken from the Surface of 
 Ditches. The Motion of their Inteft ines are 
 perfectly fingular and diflinguiihable, and 
 they are Objects well deierving our particu- 
 lar Obfervation. 
 
 * Vid. Swammer.. Hijl. Generate des Infeft. p. 148. 
 
 CHAP. 
 
[ 2o 9 ] 
 CHAP. XXVIII. 
 
 Of the Stings of Infetts. 
 
 ' I 'HE fl:arp and penetrating Inftruments 
 ** wherewith the Tails of Bees, Wafps, 
 Hornets, Ants, and fome other IniVdts are 
 armed, I diftinguifh by the Name of Stings : 
 being Weapons given them by Nature to de- 
 fend themfelves and offend their Enemies ; 
 whereas the Trunk or Probofcis which Gnats, 
 Fleas, Lice, and many other Kinds carry in 
 their Mouth, though it may be equally fharp, 
 is not intended as an Inflrument of Revenue, 
 but for procuring and fucking in their Food ; 
 and, therefore, when fuch Creatures bite or 
 iling us, as we term it, we muft not ima- 
 gine they do fo out of Anger, but from Ne- 
 ceffity. Squeeze or ftrike a Bee or Wafp, 
 it inftantly puts forth its Sting, but no Pro- 
 Vocation can urge a Gnat or Flea to bite: 
 on the contrary, when difturbed or hurt they 
 draw in their Probofcis infteadof thrufling it 
 out, and never make Ufe of it but when 
 they think themfelves perfectly fafe and quiet. 
 There is belides this farther Difference ; a 
 Sting injecls a venomous Liquor into the 
 Wound it makes, but a Probojcis fucks or 
 draws out the Blood and Humours from it. 
 
 As 
 
210 Of a Bee'i Sting. 
 
 As the Structure and Contrivance of mod 
 Stings are nearly alike, bydefcribing one the 
 reft will be underftood : I (hall, therefore, 
 give a brief Account of the Sting of a Bee, 
 as difcovered by the Micro/cope. 
 
 CHAP. XXIX. 
 
 Of a Bee's St big. 
 
 / T^HE Sting of a Bee is a horny Sheath or 
 ■** Scabbard that includes two bearded 
 Darts. This Sheath ends in a (harp Point : 
 near the Extremity whereof a Slit opens, 
 through which, at the Time of flinging, two 
 bearded Darts are protruded beyond the End 
 of the Sheath ; one whereof being a little 
 longer than the other, fixes its Beard nrft *, 
 but the other inftantly following, they pene- 
 trate, alternately, deeper and deeper, taking 
 hold of the Flefh with their Hooks, till the 
 whole Sting becomes buried in the Wound ; 
 and then a venomous Juice is injected, thro* 
 the fame Sheath, from a little Bag at the 
 Root of the Sting, which occafions an acute 
 Pain, and a Swelling of the Part, continu- 
 ing fometimes feveral Days. This is beft 
 prevented, by enlarging the Wound imme- 
 diately to give it fome Difcharge. 
 
 The 
 
Of a BeeV Sting. 2 1 1 
 
 The two Darts lye within the Sting as in 
 Plate XIII. Fig. X. a. 
 
 When thruft out they appear as in Fig. X. b. 
 
 Mr. Derham fays, he counted, in the 
 Sting of a JValp, eight Beards on the Side of 
 each Dart, fbmewhat like the Beards of Fiih- 
 Hooks, and I have obferved the fame Num- 
 ber in that of a Bee. When thefc Beards are 
 ftruck deep in the Fleih, if the wounded 
 Perfon ftarts before the Bee can dilengage 
 them, me leaves her Sting behind flicking 
 in the Wound : but if he has Patience to 
 ftand quiet, till (lie brings the Hooks dole 
 down to the Side of the Darts, me withdraws 
 her Weapon, and the Wound becomes much 
 lefs painful. A Wafp is not lb liable as a Bee 
 to leave its Sting behind, the Beards of it be- 
 ing rather fborter, and the Animal ftronger 
 and more nimble. * 
 
 To view the Sting of a Bee by the Mi- 
 cro/cope, cut off the End of its Tail, and 
 then touching it with a Pin or Needle, it 
 will thruft out the Sting and Darts, which 
 may be fnipt off with a Pair of Sciffars and 
 kept for Obfervation. Alfo, if you catch a 
 Bee in a Leather Glove, its Sting will be 
 
 * Vid. DERHAM'sPJnf. Theol.p. 241. Sped, de la Nat. 
 Dial. VI 
 
 P 2 left 
 
212 Of the Sting of a Scorpion. 
 
 left therein, being unable to difengage its 
 Hooks from Leather : and when it is quite 
 dead, which it will not be till after feveral 
 Hours, you may by Care and Gentlenefs ex- 
 tract it with its Darts and Hooks. By 
 fqueezing the Tail, pulling out the Sting, 
 and prefiing it at the Bottom, you may like- 
 wife force up the Darts ; but without fome 
 Practice this will be a little difficult. 
 
 The Bag containing the poifonous Juice 
 may eafiiy be found at the Bottom of the 
 Sting, and examin'd, being commonly pul- 
 led out with it : and, by letting the Bee 
 ftrike its Sting upon fome hard Body, enough 
 of the faid juice may be obtained to put upon 
 a Slip of Glafs, in order to view the Salts, 
 floating therein at firft, and afterwards 
 lliooting into Cryftals. 
 
 CHAP. XXX. 
 
 Of the Sting of a Scorpion. 
 
 OW far the Sting of a Scorpio?! is of a 
 like Structure with that of a Bee I ne- 
 ver had the Opportunity of examining, as 
 none of them are brought alive to England ; 
 but the Curious that go abroad into hot Coun- 
 tries, where they are produced, would do 
 well to obferve, particularly, whether a Dart 
 2 or 
 
Of the Sting of a Scorpion. 213 
 
 or Darts are not Ihcathed in the horny Sting 
 at the Extremity of their Tail. 
 
 The Opinions of Authors are very diffe- 
 rent as to this Creature's having or not hav- 
 ing any opening in its Sting, through which 
 a Poifon iilues into the Wound it makes. 
 Galen fays, there is none : Pliny, Ter- 
 tulli an, Elian, Aldrovand and others 
 affert, on the contrary, that there is. But I 
 think this Matter is let in the trued Light 
 by Seignior Redi, that diligent Natura- 
 lift, who took the Pains to examine Scorpions 
 brought from Tunis, from Egypt, and 
 from Italy, in order to difcoverthis Aper- 
 ture, with two of the beft Micro/copes in 
 the Mufaum of the Grand Duke of Tus- 
 cany, one whereof was made at Rome, 
 and the other in England: but, though 
 thefe GlafTes were excellent, he was unable 
 to difcern the lealt Perforation. However, 
 not iatisfied with only viewing them, he en- 
 deavoured, by Preffure, to fqueeze from the 
 Cavity of the Sting any Liquor it might con- 
 tain ; but he found it fo hard and horny, . 
 that Squeezing could have no Effect. He, 
 moreover, caufed a Scorpio?i to ftrike on a 
 Plate of Iron, but no Moifture appeared 
 thereon ; fo that he began to conclude Ga- 
 len's Opinion right ; when he difcovered, 
 accidentally, an exceeding fmall and almoft 
 invifible Drop of white Liquor upon the 
 
 P 3 Sting i 
 
214 Of the Sting of a Scorpion. 
 
 Sting * j which convinced him that Elian 
 fays true, where he afTerts, that the Perfo- 
 ration in a Scorpions Sting is fmall beyond 
 the PoiTibility of being feen. And fuch a 
 Drop he frequently faw afterwards, in the 
 Progrcfs of his Experiments, on the Stings 
 of fevei al Scorpions, at the Time of their 
 Striking : which Drop, entering the Wound, 
 produced the mofl fatal Effects -j-. 
 
 What a virulent and furprizing Poifon 
 mud this be ! that, in fo very minute a 
 Quantity, can contaminate the whole Mafs 
 of the Fluids, and bring on fudden Death, 
 not only in Man and other fmaller Creatures, 
 but even in Lions, Camels and Elephants, as 
 we are aflured it will ! How fubtile, how 
 penetrating, how divifible, mult the com- 
 ponent Particles of this little Speck of Ve- 
 nom be ! and how ftrong a Proof it affords, 
 that the greater! Changes imaginable may be 
 wrought in the human Body, by the Ad- 
 mixture of different Liquors with the Blood, 
 even in the fmaliefl Quantities ! 
 
 * Vid. Red i de Gener. Jnfeft. p. 127. 
 
 f Mr. Leeuwenhoek difcovered an Opening on each 
 Side of the Sting for the Emiffion of this Poifon; which he 
 fuppofes is not difcharged till the Sting is buried in the Wound. 
 Vid. Arc. Nat. Tom. II. p. 167. 
 
 CHAP. 
 
[2i 5 J 
 
 CHAP. XXXI. 
 
 Of tie Poifon of a Viper. 
 
 / T A HE Mifchief done by the Viper \ or any 
 
 ■** other Serpent, is not effected by means 
 of a Sting, (for what is darted out of its 
 Mouth, and by the vulgar fuppofed a Sting, 
 is nothing but the Tongue of the Animal, 
 and perfectly harmlefs:) but its Teeth arc 
 the dreadful Weapons wherein the Poifon 
 lies, and its Bite is all we need to' fear. 
 
 Dr. Mead, in his molt valuable EfTay on 
 the Poifon of the Viper ; has defcribed thefe 
 Teeth and their Poiion lb much better than 
 it is poffible for me to do, that I fhall beg 
 Leave to borrow the chief I have to fay from 
 him. 
 
 The poifonous Fangs or great Teeth are 
 crooked and bent : they are hollow from 
 the Root a confiderable Way up, not to the 
 very Point, (which is folid and (harp to pe- 
 netrate the better) but to within a little Dif- 
 tanceof it: as may be feen by fplitting a Tooth 
 through the Middle. This Cavity ends in a 
 vifible Slit refembling a Nip or Cut of a Pen. 
 See Plate XIII. Fig. XI. The Poifon is 
 ejected through this Slit from a Bag at the 
 Root of the Teeth, into which it is difcharg'd 
 by a Du6r jult behind the Orbit of the Eye, 
 P 4 from 
 
216 Of the Poifon of a Viper. 
 
 from a conglomerated Gland that feparates it 
 from the Blood. 
 
 The venomous Juice of the Viper may be 
 got by enraging it till it bites on fomething 
 folid. This Juice the Doctor put carefully 
 on a Glafs Plate, and examined it by the Mi- 
 crofcope. Upon the firft Sight he could dif- 
 cover nothing but a Parcel of fmall Salts nim- 
 bly floating in the Liquor : but in a very 
 fhort Time the Appearance was changed, 
 and thofe faline Particles were now fhot out 
 as it were into Cryftals of an incredible 
 Tenuity ox Sharpnefs, with fomething like 
 Knots r here and there, from which they 
 feemed to proceed : fo that the whole Tex- 
 ture did in a manner reprefent a Spider's 
 Web, though infinitely finer and more mi- 
 nute; and yet withal, fo rigid were thefe 
 pellucid Spicula or Darts, that they remain'd 
 unaltered upon his Glafs for feveral Months. 
 And^ by confidering the necefTary Effects of 
 fuch Spicula in the Blood, this learned Phy- 
 fician accounts very reafonably for all the 
 Symptoms ufually fucceeding the Bite of 
 this Animal. 
 
 Galen fays, the Mountebanks of his Time 
 ufed, with fome kind of Parte, to flop the 
 Perforations in the Teeth of Vipers , whereby 
 they kept in the Venom ; and then would 
 fiiffer themfelves to be bit, pretending their 
 Antidotes prevented any ill Effects. 
 
 CHAR 
 
[ 2 *7 ] 
 CHAP. XXXII. 
 
 Of the Snail. 
 
 THE * Snail ha& four Eye.-, at the End 
 of optic Nerves, (heathed in her Horns, 
 which the can draw in, or thrufl out, turn, 
 or direct, as fhe finds moft convenient. 
 
 When the Horns are out, cut off nimbly 
 the Extremity of one of them, and, placing 
 it before the Micro/cope, you may difcover 
 the black Spot at the End to be really a 
 Scmiglobular Eye. 
 
 The Diflcction of this Animal is very cu- 
 rious ; for the Micro/cope does not only fhew 
 the Heart, beating, jufi: againft a round Hole 
 near the Neck, which feems the Place of 
 Refpiration ; but alfo the Liver, Spleen, 
 Stomach, Veins, Arteries, Guts, Mouth and 
 Teeth. The Guts are green, from the Crea- 
 ture's eating Herbs, and branched all over 
 with fine capillary white Veins. The Mouth 
 is like a Hare's or Rabbet's, with four or fix 
 Needle-Teeth refembling thofe of Leeches , 
 and of a Subftance like Horn. 
 
 Snails are all Hermaphrodites, having 
 both Sexes united in each Individual. They 
 lay their Eggs with great Care in the Earth ; 
 
 * Vide Power's Oijh-v. p. 38. Lister Exerc. Ana- 
 torn. Cocbl. — Speft. de la Nature, Dial. XI. 
 
 and 
 
2 1 8 Of the Snail. 
 
 and the young ones come out, when hatch- 
 ed, with Shells compleatly formed, and of 
 a Minutenefs proportionable to their own 
 Size. Thefe little Shells enlarge, as the 
 Snails advance in Growth, by the Addition 
 of new Circles, of which Circles they always 
 continue to be the Center. 
 
 Cutting oft* a Snail's Head, a little Stone 
 appears, -f- which from fts diuretic Quality is 
 offineul i Sei vice in gravelly Diforders. Im- 
 mediately under this Stone the beating Heart 
 is feen, with its Auricles, which are mem- 
 branous ; all of a white Colour, as are alio 
 the Veflels iffuing therefrom. This, little 
 Stone feems intended to ferve inftead of a 
 Breaft-Bone, which moft other Creatures 
 have. 
 
 It is very remarkable that Snails dis- 
 charge their Excrements at an Opening in 
 the Neck, that they breathe there, and that 
 both their male and female Parts of Genera- 
 tion are fituated near the fame Place. The 
 male Part is very long, and in Shape refem- 
 bles the Penis of a Whale. 
 
 j[Vide Swammerdam Hift. Gener . des Infe&es. p. 77. 
 
 CHAP. 
 
t 219 ] 
 
 CHAP. XXXIII. 
 
 Of the common Fly. 
 
 ^T^HE common Fly is adorn'd with Beau- 
 **- ties not to be conceived without -iMi- 
 crofcope. It is ftudded from Head to Tail 
 with Silver and Black, and its Body is all 
 over befet with Briitles pointing towards the* 
 Tail. The Head of it contains two large 
 Eyes, encircled with Borders of Silver Hairs ; 
 a wide Mouth, with an hairy Trunk or In- 
 ftrument to take in its Food : a Pair of fhort 
 Horns, fcveral ftiff black Briitles, and many 
 other Particulars difcoverable by the Micro- 
 fcope*. Its Trunk confifts of two Parts, fold- 
 ing over one another, and ihcathed in the 
 Mouth. The Extremity thereof is lharp 
 like a Knife, for the Separation of any thing. 
 The two Parts can alfo be form'd, occasion- 
 ally, into a Pair of Lips for taking up pro- 
 per Quantities of Food, and by the F/y's 
 fucking in the Air, they become a kind of 
 Pump, to draw up the Juices of Fruits or 
 other Liquors. 
 
 Some Flies are much lighter coloured and 
 more tranfparent than others, and in fuch 
 the Motion of the Guts may be feen very 
 
 * Speftacle de la Nat. Dial. VII. 
 
 diflinclly, 
 
220 Of the common Fly. 
 
 diftinctly, working from the Stomach to- 
 wards the Anus ; and alfo the Motion of 
 the Lungs, contracting and dilating them- 
 felves alternately. Upon opening a Fly, 
 numberlefs Veins may likewife be difcover'd 
 difperfed over the Surface of its Inteftines : 
 for the Veins being blackifh, and the Intef- 
 tines white, they are plainly vifible by the 
 Micro/cope, though two hundred thoufand 
 Times ilenderer than the Hair of a Man's 
 Beard. According to Mr. JLeeuwenhoek, 
 the Diameter of four hundred and fifty fuch 
 minute Veins were about equal to the Dia- 
 meter of a fingle Hair of his Beard ; and 
 confequently, two hundred thoufand of them 
 put together would be about the Bignefs of 
 fuch an Hair. 
 
 In moft kinds of Flies, the Female is 
 furnimed with a moveable Tube at the End 
 of her Tail, by extending of which fhe 
 can convey her Eggs into convenient Holes 
 and Receptacles, either in Flefh, or fuch 
 other Matters as may afford the Young Ones 
 proper Nourishment. From the Eggs come 
 forth minute Worms or Maggots, which 
 after feeding for a while, in a voracious Man- 
 ner, arriving at their full Growth, become 
 transformed into little brown Aurelias j 
 
 % Are. Nat, Tom. II. p. 77. 
 
 whence^ 
 
Of the Weevil. 22 1 
 
 whence, after fome time longer, they illuc 
 perfect Flies. 
 
 It would be endlefs to enumerate the dif- 
 ferent Sorts of Flies^ which may continually 
 be met with in the Meadows, Woods and 
 Gardens : and impoffible to defcribe their 
 various Plumes and Decorations, furpafTing 
 all the Magnificence and Luxury of Dreis 
 in the Courts of the greateft Princes. Every 
 curious Obferver will rind them out himfelf, 
 and, with Amazement and Adoration, lift 
 up his Eyes from the Creature to the 
 Creator. 
 
 CHAP. XXXIV. 
 
 Of the Weevil, or Corn-Beetle. 
 
 ^T^HE Weevil and the IFo/fare two kinds 
 ■*- of imall Infecls that do abundance of 
 Mifchief to many Sorts of Grain, by eat- 
 ing into them and devouring all their Sub- 
 fiance. 
 
 The Weevil is fomewhat bi^er than a 
 large Loufe, of the Scarab Kind, with two 
 pretty jointed tufted Horns, and a Trunk 
 or Peircer projecting from the Fore-part of 
 its Head; at the End of which Trunk (which 
 is very long in Proportion to its Body) are a 
 fort of Forceps or fharp Teeth, wherewith 
 it gnaws its Way into the Heart of the 
 
 Grain, 
 
222 Of the Weevil. 
 
 Grain, either to feek its Food or depofit its 
 Egffs there. 
 
 By keeping thefe Creatures in Glafs 
 Tubes, with fome few Grains of Wheat, 
 their Copulation has been difcovered, and 
 likewife their Manner of Generation, which 
 
 is thus. * The Female perforates a Grain 
 
 of Wheat, and therein depofits a fingle ob- 
 long Egg, or two Eggs at mofr, (a Grain of 
 Wheat being unable to maintain above one or 
 two of the young Brood when hatch'd)and this 
 fhe does to five or fix Grains every Day for fe- 
 veral Days together. Thefe Eggs, not above 
 the Size of a Grain of Sand, in about feven 
 Days produce an odd fort of white Maggot, 
 which wriggles its Body pretty much, but 
 is icarce able to move from Place to Place, 
 as indeed it has no occafion, being happily 
 lodged by its Parent where it has Food e- 
 nough. This Maggot turns into an Aurelia, 
 which in about fourteen Days comes out a 
 perfect Weevil. 
 
 As many People are unacquainted with 
 the Weevil, a Picture of it is given Plate XIII. 
 Fig. XII. 
 
 Weevils when in the Egg, or not come 
 to their perfect State, are often devoured by 
 Mites. 
 
 -f- Vide Leeuwen. Epift. de Sexto Augufti 1687. ad 
 "Keg Societ. 
 
 CHAP. 
 
t 22 3 1 
 
 CHAP. XXXV, 
 
 Of the Wolf. 
 
 / Hp H E Wolf is a little white Worm or 
 ■** Maggot that in felts Granaries and Corn- 
 chambers, and unlefs proper Care be taken, 
 will do unfpeakable Damage.— I call it a 
 Worm, or Maggot, becaufe under that Form 
 it does the Mifchief, though in its perfect 
 State it is really a fmall Moth, whofe Wings 
 are white, fpotted with black Spots. 
 
 This little Maggot has fix Legs ; and, as 
 it creeps along, there iflues from its Mouth 
 an exceeding fine Thread or Web, by which 
 it fattens itfelf to every thing it touches, fo 
 that it cannot fall. Its Mouth is armed with 
 a pair of reddifli Forceps or biting Inftru- 
 ments, wherewith it gnaws its Way not on- 
 ly into Wheat and other Grain, but perfo- 
 rates even wooden Beams, Boxes, Books, 
 and almoft any thing it meets with. 
 
 Towards the End of Summer, this per- 
 nicious Vermin (in Corn-chambers infefted 
 with them) may be feen crawling up the 
 Walls in great Numbers, in fearch of pro- 
 per Places where they may abide in Safety 
 during their Continuance in their Aurelia 
 State : for when the Time of undergoing a 
 Change into that State approaches, they for- 
 i fake 
 
224 « Of the Wolf. 
 
 fake their Food, and the little Cells they had 
 formed of hollowed Grains of Corn, clotted 
 together by means of the Web coming from 
 their Mouths, and wander about till they 
 find fome Wooden Beam, or other Body to 
 their Mind, into which they gnaw Holes 
 with their fharp Fangs, capable of conceal- 
 ing them : and there, enveloping themfelves 
 in a Covering of their Own Spinning, foon 
 become metamorphofed into dark- coloured 
 Aurelias -j-. 
 
 Thefe Aurelias continue all the Winter 
 unactive and harmlefs, but about April or 
 May, as the Weather grows warm, they 
 are transformed a-new, and come forth 
 Moths of the Kind above defcribed. They 
 may then be feen in great Numbers taking 
 little Flights, or creeping along the Walls ; 
 and, as they eat nothing in their Fly-State, 
 are at that Time not milchievous. But they 
 foon copulate and lay Eggs (fhaped like 
 Hen's Eggs, but not larger than a Grain of 
 Sand) each Female fixty or feventy, which, 
 by means of a Tube at the End of her Tail, 
 ihethruits or infinuates into the little Wrinkles, 
 Hollows, or Crevices of the Corn j where, 
 in about fixteen Days they hatch, and then 
 the Plague begins : for the minute Worms 
 or Maggots immediately perforate the Grain 
 
 ■\ F/^Leeuwen Experiment. & Contempl. Epift. 7*- 
 
 they 
 
Of the Wolf. 225 
 
 they were hatched upon, eat out the very- 
 Heart of it, and with their Webs cement 
 other Grains thereto, which they likewife 
 icoop out and devour, leaving nothing but 
 Hulks, and Dull, and fuch a quantity of 
 their Dung as Chews them to be more vo- 
 racious Infe&s than the Weevil. 
 
 The watchful Obfervcr has two Opportu- 
 nities of deifroying this Vermin, if they hap- 
 pen to be got among his Corn. One is, when 
 they forfake their Food and afcend the Walls, 
 which they will ibmetimes almoft cover : 
 the other, when they appear in the Moth 
 State. At both thefe Times they may be 
 cruthed to Death again ft the Walls in great 
 Numbers by clapping Sacks upon them. 
 But they may hall be exterminated more 
 effectually, if doling up all the Doors and 
 Windows, the Corn-Chamber be filled with 
 the Fumes of Brimftone i by leaving it burning 
 on a Pan of Charcoal, without giving it any 
 Vent, for twenty-four Hours. Great Cau- 
 tion, however, mull: be ufed, to open the 
 Windows and Doors, and let all the Fumes 
 be intirely gone, before any Body enters the 
 Place afterwards, for Fear of Suffocation. 
 The Fumes of Sulphur are in no wife hurt- 
 ful to the Corn, or give it any Tafte. 
 
 The Picture of the Wolf in its Reptile 
 State, (when it goes by that Name) is (hewn 
 Plate XIII. Fig. XIII, a. 
 
 Q^_ Its 
 
226 Of the pearled Eyes of Infects. 
 
 Its Appearance when transformed into a 
 Moth is feen Fig XIII b. 
 
 Old Corn is lefs fubjecl to thefe devour- 
 ing Infects than Corn that is new ; for its 
 Skin being more hard and dry, it is much 
 more difficult for the little Maggots when 
 firil hatch'd to penetrate*. 
 
 CHAP. XXXVI. 
 
 Of the pearled Eyes of\ Insects. 
 
 / "T^HE Eyes of Infects arc amazing Pieces 
 ■** of Mechanifm, whofe Structure and 
 Difpoiition without the Affiftance of the 
 Microjcope would for ever have been un- 
 known to us. — Beetles, Dragon-flies, Bees, 
 Wafps ) Ants, common Flies, Butterflies, and 
 many other Infec~is have two Crefcents, or 
 immoveable Caps compoling the greateir. 
 Part of the Head, and containing a prodi- 
 gious Number of little Hejnifpheres or round 
 Protuberances, placed with the utmoft Re- 
 gularity and Exactnefs in Lines eroding each 
 other, and refembling Lattice- Work. Thefe 
 
 * I call this InfecT: the Wolf from the Latin Name Lupus i 
 given, I fuppofe, for its Voracioufnefs. 
 
 + Vide Speftacle de la Nature, Dial. VIII. Hook's 
 Microg. p. i 80. Leeuw. Arc. Nat. Tom. II. PartII.p.41. 
 again,p. 424. Der ham's Phyf. Theolog, p. 364. 
 
 2 are 
 
Of the pearled Eyes of Infects. 227 
 
 areaCollection of Eyes, fo perfectly fmooth 
 and polifhed, that like fo many Mirrors they 
 reflect: the Images of all outward Objects. 
 One may fee the Figure of a Candle multi- 
 plied almoft to Infinity on their Surfaces, 
 Shifting its Beams into each Eye, according to 
 the Motion given it by the Obferver's Hand: 
 and as other Creatures are obliged to turn 
 their Eyes to Objects, this Sort have fome 
 or other of their Eyes always ready directed 
 towards Objects on whatever fide they pre- 
 fent themielves. In fhort, all thefe little 
 Hemijpheres are real Eyes, having in the mid- 
 dle of each a minute tranlparent Lens and 
 Pupil, through which Objects appear topfy 
 turvy as through a convex Glafs : This be- 
 comes alfo a Jmall Teleftope when there is a 
 juft focal Diftance between it and the Lens 
 of the Micro/cope. It is alfo reafonable to 
 believe, that every Lens has a dillinct Branch 
 of the Optic Nerves adminiftring to it : and 
 yet, that Objects are not multiplied, or ap- 
 pear otherwile than fingle, any more than 
 they do to us, who fee not an Object dou- 
 ble though we have two Eves. 
 
 Every Man almoft that has feen a Micro- 
 fcope has been entertained with a View of 
 thefe minute Eyes, and yet very few perhaps 
 have well confide r'd either the Nature or 
 the Number of them. Mr. Hooke com- 
 puted fourteen thoufand Hemijphercs in the 
 
 Q^2 tWO 
 
228 Of the pearled Eyes of Infects. 
 
 two Eyes of a Drone , viz, feven thouiand 
 in each Eye. Mr. Leeuwenhofk reckon- 
 ed fix thouiand two hundred thirty-fix in a 
 Si Ik- Worm's two Eyes, when in its Fly- irate: 
 three thoufand one hundred eighty one in 
 each Eye of a Beetle : and eight thoufand 
 in the two Eyes of a common Fly. The 
 Libella, Adder- Bolt ', or Dragon- Fly, is the 
 moil remarkable of all the Infects we know 
 for its large and fine pearled Eyes ; which 
 even with a common Reading- Glafs appear 
 like the Skin we call Shagreen. Mr. Leeu- 
 wenhoek reckons in each Eye of this 
 Creature, twelve thoufand five hundred forty 
 four Lenjes, or, in both, twenty-five thou- 
 fand eighty-eight ; placed in an hexangular 
 Pofition, each Lens having fix others round 
 it j which is alfo the Order moft common in 
 other Eyes. He likewife obferved in the 
 Center of each Lens a minute tranfparent 
 Spot, brighter than the reft, and fuppofed to 
 be the Pupil, through which the Rays of 
 Light are tranfmitted upon the Retina. This 
 Spot had three Circles furrounding it, and 
 teemed feven times lefs than the Diameter 
 of the whole Lens. We fee here, in each 
 of thefe exceedingly minute lenticular Sur- 
 faces, as much Accuracy in the Figure and 
 Polifh, and as much Contrivance and Beau- 
 ty as in the Eye or a Whale or an Elephant : 
 and how delicate, how exquifitely delicate 
 muit the Filaments of the Retina be which 
 
 ferve 
 
Of the pearled Eyes of Infects. 229 
 
 ferve to each of thefe, fince the whole Pic- 
 ture of Objects painted thereon, mud be 
 Millions of times lefs than the Images of 
 them pictured on the human Eye ! 
 
 If we cut off the Eye of a Dragon Fh\ 
 of a Drone, or of a common F/\\ and with 
 a Pencil and fome clean Water wafh out 
 all the Veflels, thofe VeiTels may be cxa- 
 min'd by the Micro/cope, and the Numbers 
 of them will appear wonderful and furpriz- 
 ing ; and then, if the outward Covering be 
 dryed carefully, fo as not to (brink, it will 
 be rightly prepared for making Experiments 
 with the Micro/cope, and upon viewing it 
 we (hall perfectly diftinguilh the numerous 
 Protuberances or Uemifpheres divided from 
 one another, with a fmall Light ifiuing be- 
 tween them, and fix Sides to each. Mr. 
 Leeuwenhoek having prepared an Eye 
 in this Manner, placed it a little farther 
 from his Micro/cope than when he would exa- 
 mine an Object : fo as to leave a right and 
 exact focal Di fiance between it and the hens 
 of his Micro/cope y and then, looking thro' 
 both in the Manner of z'Telcfcope, at the 
 Steeple of a Church, which was two hun- 
 dred ninety and nine Feet high, and feven 
 hundred fifty Feet from the Place where he 
 ftood, he could plainly fee,through every little 
 Lens, the whole Steeple, inverted, tho' not lar- 
 ger than the Point of a fine Needle : and then, 
 Q^3 direct- 
 
2 3° Of ^- e Antennas, Feelers, 
 directing his View to a neighbouring Houfe, 
 he faw through abundance of the little He- 
 mifpberes, not only the Front of the Houfe, 
 but likewife the Doors and Windows ; and 
 was able to difcern distinctly whether the 
 Windows were fhut or open. 
 
 There can be no doubt, that Lice, Mites, 
 and multitudes of other Animalcules, much 
 fmaller ft ill than they, have Eyes contrived 
 and fafhion'd, to difcern Objects fome thou- 
 fands of times lefs than themfelves : for fo 
 the minute Particles they feed on, and ma- 
 ny other Things neceffary for them to di- 
 ftinguifti and know perfectly, muft certainly 
 be. — What a Power then of magnifying are 
 fuch Eyes endued with ! and what extra- 
 ordinary Difcoveries might be made, were 
 it poffible to obtain Glafles through which 
 we could fee as they do ! 
 
 CHAP. XXXVII. 
 
 Of the Antennae, Feelers, or Horns of 
 Insects. 
 
 '"T" V H E Horns of Infetts have been thought 
 
 **• by many defigned only to clean their 
 
 Eyes, by wiping off any Dufl that may fall 
 
 thereon : but as we constantly obferve them 
 
 perform- 
 
or Horns of Infects. 231 
 
 performing that Office with their Fore-legs, 
 'tis certain their Horns muff, be intended for 
 fome other Purpofe. And fince they are 
 perpetually feeling before them with their 
 Antenna as they walk along*, Mr. De r h am 
 very reafonably imagines them abfolutely 
 necerTary to fearch out and find their Way. 
 For as their Eyes are immoveable, fo that 
 no Time is required for their turning them 
 to Objects, there is no NecefTity that the 
 Retina, or optic Nerve, fhould, occafionally, 
 be brought nearer to, or removed farther 
 from the Cornea, as it is in other Animals ; 
 which would require Time : but their Cornea 
 and Optic Nerve being always at one and 
 the fame Diftance, and fitted only to fee dif- 
 tant Objects ; they would be infenfible of, 
 and apt to run their Heads again ft Bodies 
 very near them, were they not ailifted by 
 their Feelers. 
 
 And that this, rather than wiping the Eyes, 
 is the chief Ufe of the Feelers, is farther 
 manifeft from the A?itenna of the Flejh- 
 Fly, and many other Infects, which are fhort 
 and ftrait, and uncapable of being bent 
 down to, or extended over the Eyes : as al- 
 fo from others enormoufly long, fuch as 
 thofe of the Capricorni or Goat Chafers, 
 the Cadew Fly, and divers others both Beetles 
 and Flies. 
 
 * Der ham's Phyf. Theol. p. 36;. 
 
 CL4 The 
 
2 3 2 Of ( ' je ^i n S s °f Infers. 
 
 The lamellated Antenna of fome, the 
 clavellated of others, the Topknots or Tufts 
 like Dandelion Seeds, the branched, the fea- 
 thered, and divers other Forms of Horns of 
 the Beetle, Butterfly, Moth, Gnat, and many 
 Kinds befide, are farprizingly beautiful when 
 viewed through a Microfcope. And, in fome, 
 thefe Antenna? diftinguifh the Sexes j for in 
 the Gnat-kind all thofe with Tufts, Feathers, 
 or Brufh-Horns (of which there are great Va- 
 rieties) are Males : thofe with fhort fingle- 
 fhaited Horns are Females. 
 
 CHAP. XXXVIII. 
 
 Of the Wings of Insects. 
 
 'HpHERE is fuch infinite Variety in the 
 ■*■ Contexture, Formation, Difpofition and 
 Ornaments of the Wings of InfcSls, accord- 
 ing to their different Wants and Ways of 
 Life, that nothng but a curious Obfervation 
 can make us have any true Conception of it. 
 Some Wings are filmy, as thofe of Dragon- 
 flies ; others are ftuck over with fhort Brif- 
 tles, as in Flefi-flies ; fome are Films co- 
 vered with fhort Feathers, like the Tiles of 
 a Houfe, as in Butterflies and Moths ; others 
 have divided Wings, as the grey and white 
 2 . feathered 
 
Cf the Wings of Infe&s. 233 
 
 feathered-Moth. The Wings of many forts 
 of Gnats are adorned with Rows of Fea- 
 thers along their Ridges, and Borders of 
 Feathers round their Edge. Some, again, 
 have Hairs, and others Hooks, placed with 
 the greateft Regularity and Order. All of 
 the Scarab Kind have Elytra, or Cafes, into 
 which their Wings are folded and preferved 
 until they want to employ them. Some of 
 thefe Cafes reach almoit to the Extremity of 
 the Tail, as in mod: Kinds of Beetles ; and o- 
 thers are very fhort, as in the Earwig. Many 
 of them are likewife extreamly beautiful 
 when brought before the Microfcope. 
 
 All thefe Kinds cf Wings have certain bo- 
 ny Parts or Ribs, that give them Strength, 
 along the Sides of which run large Blood- 
 VelTels branching out into numberlefs Divi- 
 fions, and conveying Nourifhment to the in- 
 termediate Parts : for though no Circulation 
 can be difcerned in them, it being probably 
 extreamly flow, we can fcarce doubt that 
 there mutt be continually a Supply of Jui- 
 ces to the Quills, Hairs, or Briftles where- 
 with they are armed or ornamented. 
 
 As to Motion, Wings that are filmy move 
 fader than thofe cover'd with Feathers. Mr. 
 Hook obferves, that in the Wings of fome 
 minute Flies there are many Hundreds, if not 
 Thoufands of Vibrations in a Second, and 
 fuppofes them the fwifteft Vibrations in the 
 
 World : 
 
2 34 Of ^ je Wings °f Infects. 
 
 World : whence he reflects, very ingenious- 
 ly, on the Quicknefs of the Animal Spirits, 
 that ferve to fupply this Motion. 
 
 Thofe converfant in Microfcopes need not 
 be informed, that the beautiful Colours on 
 the Wings of Butterflies and Moths are ow- 
 ing to elegant minute Feathers, ending in 
 Quills, and placed with great Exactnefs in 
 orderly Rows ; as when rubbed off, the Holes 
 they come from fhew : but few, it may be, 
 have much obferved the great Variety of their 
 Make : not only in Moths and Butterflies of 
 different Sorts, but even in thofe taken from 
 different Parts of the fame Wing ; infomuch 
 that it is pretty difficult to find any two 
 of them exactly alike. 
 
 Rub thefe Feathers gently off, with the 
 End of your Finger or Pen-knife j and, 
 breathing upon a fingle Talc in one of 
 your Sliders, apply it to the Feathers which 
 feem only like a fine Duft, and they will im- 
 mediately adhere to it : then placing it be- 
 fore the Micro/cope, if they are not perfect, 
 or lye not to your Mind, wipe them on, 
 and put on others in the fame Manner, till 
 you get thofe you like : then cover them with 
 another tfalc, and faften it down with a 
 Wire, that you may preferve them for future 
 Examination. Look at them with the third 
 or fourth , then with the fecond, and at lafl 
 with the greatefi Magnifier, 
 
 The 
 
Of the Ballances or Poifes 0/" Infects. 235 
 
 The Wing of a Midge is a mod: curious 
 Object, and fo indeed is every Part of that 
 minute Infect. The Wing of the little Flume 
 Moth is compofed of feveral diftinct Quills, 
 like thofe of Birds. There are alfo Wines 
 folded up in the little Cafes on the Backs of 
 Earwigs, very pretty to examine. But no 
 more need be laid of Wings, fince every 
 Body mult be fenfible the great Variety of 
 them is an endlefs Subject of Enquiry and 
 Admiration. 
 
 CHAP. XXXIX. 
 
 Of the Ballances or Poifes of Infects. 
 
 "j\/TOST Infects having but two Wings, are 
 ■**-■■ provided with a little Ball or Bladder 
 under each, fet at the Top of a (lender Foot- 
 ftalk, which is moveable every Way at Plea- 
 fure. With thefe they ballance themfelves 
 in Flight as a Rope- Dancer does with his Pole 
 leaded at each End ; and if one of them be 
 cut off, the Creature flies for a while very 
 awkardly, as if over-heavy on one Side, and 
 falls at laft to the Ground. Thefe Bladders 
 being hollow may ferve likewife to produce 
 the Noife many Sorts of Flies make, by 
 ftriking their Wings again ft them, and be a 
 Means of finding out one another. In fome 
 
 Creatures 
 
23 ^ Of the Scales of Fifties. 
 
 Creatures they ftand alone, but the whole 
 Fly-Tribe have little Covers or Shields under 
 which they lye and move. Infects that have 
 four Wings ballance themfelves with the two 
 lefTer Ones, and, as they want not, have none 
 of thefe little Poifes. The Microj'cope may 
 probably find out ftill farther Beauties, Con- 
 trivances and Ufes for them than have been 
 yet difcovered. 
 
 CHAP. XL. 
 
 Of the Scales of Fifhes. 
 
 THE Scales or outfide Coverings of Fifoes 
 are formed with furprizing Beauty and 
 Regularity ; and in different Kinds of them, 
 exhibit an endlefs Variety in Figure and Con- 
 texture. Some are longifh, fome round, 
 fome triangular, fome fquare, and fome or 
 other of all Shapes we can well imagine. 
 Some, again, are armed with fharp Prickles, 
 as thofe of the Pearch y Soal, Sec. Others 
 have fmooth Edges, as of the Cod-Fift, Carp, 
 Tench, &c. There is likewife a great Varie- 
 ty even in the fame Fifh ; for the Scales ta- 
 ken from the Belly, the Back, the Sides, the 
 Head, and all the other Parts are very dif- 
 ferent from one another. And, indeed, for 
 Variety, Beauty, Regularity, and the Order 
 
 of 
 
Of the Scales of Fillies. 237 
 
 of their Arrangement, the Scales of Fifties bear 
 a near Refemblance to the Feathers on the 
 Bodies and Wings of Moths and Butterflies. 
 
 ■c 
 
 Thefe Scales are not fuppofed to be (lied 
 every Year -f, nor during the whole Life of 
 the Filli ; but to have an annual Addition 
 of a new Scale, growing over and extending 
 every Way beyond the Edges of the former, 
 in Proportion to the Fifli's Growth ; fome- 
 what in the fame Manner as the Wood of 
 Trees enlarges yearly by the Addition of a 
 new Circle next the Bark. And as the Ace 
 of a Tree may be known by the Number of 
 Ringlets its Trunk is made up of, foin Fifhes 
 the Number of Plates compoiing their Scales 
 denote to us their Age. It is alio probable, 
 that as there is a Time of Year when Trees 
 ceafe to grow, or have any farther Addition 
 to their Bulk, the fame Thing happens to 
 the Scales in Fillies ; and that, afterwards, 
 at another Time of Year, a new Addition, 
 Increafe or Growth begins. Somewhat like 
 this in Birds and Beafts their Feathers and 
 Hairs demon fixate. 
 
 Mr. Leeuwenhoek took fome Scales 
 from an extraordinary large Carp, forty-two 
 Inches and a half long, and thirty-three and 
 a quarter in the Round, Ry/iland Meafure, 
 
 f Vid. Leeuwen. Epift, Phyfiol. E/ift. 24. Maii 1716. 
 
 which 
 
238 Of the Scales of Fifhes. 
 
 which were as broad as a Dollar. Thefe he 
 macerated in warm Water to make them 
 cut the eafier : and then cutting obliquely 
 through one of them, beginning with the 
 fii"ft form'd and very little Scale in the Cen- 
 ter, he, by his Micro/cope, plainly diftin- 
 guifhed forty Lamella or Scales, glewed as it 
 were over one another; whence he concluded 
 that the Fifh was forty Years of Age *. 
 
 It has generally been imagined that an 
 Eel has got no Scales ; but if its Slime be 
 wiped clean away, and the Skin be examin'd 
 by a Micro/cope, it will be found covered 
 with exceeding fmall Scales, ranged in a 
 very orderly and pretty Manner : and I be- 
 lieve few Fifties, unlefs fuch as have Shells, 
 are to be found without Scales. 
 
 The Way of preparing Scale 5 1 is, to take 
 them off carefully with a Pair of Nippers, 
 warn them very clean, and place them in a 
 fmooth Paper, between the Leaves of a 
 Book, to make them dry flat, and prevent 
 their (hrivelling up. Then place them be- 
 tween your Talcs in Sliders, and keep them 
 for Examination. 
 
 The Snake, the Viper, the Slow-worm, 
 the Lizard, the Eft, &c. afford a further 
 Variety of Scales. 
 
 + Arcan. Nat. Tom, III p. 214. 
 
 CHAP, 
 
t 2 39 ] 
 
 CHAP. XLI. 
 Of the Oyster. 
 
 TN the clear Liquor of an Oyfter many little 
 * round living Animalcules have been found, 
 whofe Bodies being conjoined formed fpheri- 
 cal Figures with Tails, not changing their 
 Place but by finking towards the Bottom, as 
 being heavier than the Fluid : Thefe were 
 feen fometimes leparating, and preiently af- 
 terwards coming together and joining them- 
 felves again. In other Oyfters Animalcules 
 of the fame Kind were found, not conjoined, 
 but fwimming by one another, whence they 
 feemed in a more perfecl: State, and were 
 fuppofed by Mr. Leeuwenhoek to be the 
 Animalcules in the Row or Semen, of the 
 Oyfter. * 
 
 A Female Oyfter being opened, incredible 
 Multitudes of minute Etnbryo-Oyfters cover'd 
 with little Shells perfectly tranfparent were 
 plainly feen therein, fwimming along (low- 
 ly : in another they were found of a brown- 
 ifh Colour without any apparent Life or Mo- 
 tion. Monfieur Joblot kept the Water 
 running from Oyfter s three Days, and it ap- 
 peared full of young Oyfter s that fwam a- 
 
 * Arc. Nat. Tom, 11, Par, I, p. 5 z, Again, p. 149. 
 
 bout 
 
240 Of the Oyfter. 
 
 bout nimbly, and increafed in Bignefs daily. 
 A Mixture of Wine, or the very Vapour of 
 Vinegar killed them. 
 
 In the Month of Auguft Oyflers are fup- 
 pofed to breed, becaufe young Ones are then 
 found in them. Mr. Le e u w e n hoe k 
 open'd an Oyfter on the fourth of Auguji^ 
 and took out of it a prodigious Number of 
 minute Oyfters, all alive, and fwimming 
 brifkly in the Liquor, by the Means of certain 
 exceeding fmall Organs extending a littleWay 
 beyond their Shells, which he calls their 
 Beards. In thefe little Oyjlers he could dif- 
 tinguifh the. joining of the Shells, and per- 
 ceived fome that were dead, with their Shells 
 gaping, and as like large Oyjlers in Form, as 
 one Egg is like another. 
 
 As for the Size of thefe Embryo-Oyfters, 
 he computes, that one hundred and twenty 
 of them in a Row would extend an Inch ; 
 and, confequently, that a globular Body 
 whofe Diameter is an Inch, would, if they 
 were alfo round, be equal to one Million 
 feven hundred and twenty eight thoufand of 
 them. * He reckons three or four Thou- 
 fand are in one Oyfter \ and found many of 
 the Embryo-Oyfters among the Beards, fome 
 fattened thereto by {lender Filaments, and 
 
 Vid. Arc. Nat. Tom. IV. p. 513, 
 
 others 
 
Of the Light on Oyflers. 241 
 
 others lying loofc. He lifcewife found other 
 Animalcules in the Liquor five hundred 
 times fmaller than Embryo-Oyfters. 
 
 CHAP. XLII. 
 
 Of the Light on Oysters. 
 
 IT is not very uncommon to fee on the Shells 
 ■* of Oyflers, when in the Dark, a finning Mat- 
 ter or blewijh Light like the Flame of Brim- 
 flone, which flicks to the Fingers when touch- 
 ed, andcontinuesfhiningorgivingLight a con- 
 fiderable Time, though without any fenfible 
 Heat*. Monf. Auxaut obferved this Jhining 
 Matter with a Micro/cope, and difcovered it 
 to confift of three Sorts of Animalcules. The 
 firft whitifh, having twenty-four or twenty- 
 five Legs on each Side, forked ; a black 
 Speck on one Part of the Head ; the Back like 
 an Eel with the Skin flrip'd off. The fecond 
 Sort red, refembling the common Glczv-icorm, 
 with Folds on its Back, but Legs like the 
 former, a Nofe like a Dog's, and one Eye in 
 the Head. The third Sort fpeckled, a Head 
 like a Soal, with many Tufts of whitifh 
 Hairs on the Sides thereof. He faw alio 
 fome much larger, and greyifh, having a gieat 
 
 Via. Phil. Tranfaft. Numb. 12. 
 
 R Head, 
 
242 Of the Mufcle. 
 
 Head, two Morns like a Snail's, and fix or 
 eight wbitilh Feet : but theie mined not. 
 
 As the Bodies of Lobfters and fome other 
 Kinds of Fifties, tainted Flefh, rotten Wood, 
 and other Subtfances are fometimes found to 
 ihine with a Light refembling the foregoing, 
 may it not probably proceed from the fame 
 Caufe, viz. hum Animalcules? Some have 
 alio fuppofed, that the Ignis fat uus, Will-in- 
 a-JVifp y or f ack-a-L,anthorn y is nothing elfe 
 but a Swarm of minute flying Infects, that 
 emit Light around them in the manner Glow- 
 worms do: and indeed the Motions, and fe- 
 veral other Circumftances of this Sort of Fire, 
 (if I may fo term it,) feem favourable to fuch 
 Opinion. 
 
 - The curious will judge it proper to exa- 
 mine this Matter carefully, and to them it is 
 fubmitted. 
 
 CHAP. XLIII. 
 
 Of the Muscle. 
 
 Have obferved already, in the I2jtb Page 
 of this Treatife, that a Mufcle is a moil 
 delightful Object for the Micro fcope , and 
 that in the tranfparent Membrane, adhering 
 on cither Side to the Fore-part of each Shell, 
 
 the 
 
Of the Mufcle. 243 
 
 the Blood may be feen circulating through 
 an amazing Number of VefTels, even in the 
 imalleft Particle of it that can be applied for 
 Examination. 
 
 Mr. Leeuwenhoek, in feveral that lie 
 difTected, difcovered Numbers of Eggs or 
 Embryo-Mufclcs in the Ovarium, appearing 
 as plainly as if he had feen them with the 
 naked Eye, lying with their (harp Ends 
 fattened to the Strings or VeiTels whereby 
 they receive Nourishment. Thefe minute 
 Eggs or Embryo-Mufcles, are, in due Time, 
 laid or placed by the Parent, in a very re- 
 gular and dole Order, on the Outride of 
 the Shell : where, by means of a glewy Mat- 
 ter, they adhere very fail, and continually 
 increafe in Size and Strength, till becoming 
 perfect Mufcle s y they fall off and mift for 
 themlelves, leaving the Holes where they 
 were placed behind them. This abundance 
 of Mufcle- She lis viewed by the Microfcope 
 can {hew. Sometimes two or three Thou- 
 fand of thefe Eggs adhere to the Shell of one 
 Mufcle ; but 'tis not certain they were all 
 fix'd there by the Mufcle itfelf, for they fre- 
 quently place their Eggs on one another's 
 Shells. The fring'd Edge of the Mufcle, 
 which Mr. Leeuwenhoek calls the Beard, 
 has in every the minuted Part of it fuch a 
 Variety of Motions, as is unconceivable : for 
 being compofed of longifh Fibres, each Fibre 
 has on both Sides a vail many moving Par- 
 
 R 2 tides. 
 
244 Of the Mufcle. 
 
 tides, which one would almott imagine to be 
 Animalcules -f. 
 
 The Threads or Strings, which we term 
 the Beard, are compofed of a Glew which 
 the Mufcle applies by the Help of its Trunk 
 to fome fix'd Bod)'', and draws out as a Spi- 
 der does its Web, thereby fattening itfelf, 
 that it may not be warned away. If Mufcles 
 be put into Salt and Water, we may have 
 the Pleafure of feeing them perform this 
 Work, and fatten themfelves to the Sides or 
 Bottom of the Vetted we place them in. 
 
 Cockles, Scallops, Limpets, Perriwinkles, 
 and Abundance of other Shell-Fifh, are Ob- 
 jects that have as yet been very flightly ex- 
 amin'd by the Micro/cope • and, therefore, 
 the ferious Enquirer into Nature's fecret 
 Operations may here be certain of difcover- 
 ing Beauties which at prefent he can have no 
 Conception of. 
 
 f Phil. Tranfaft. Numb. 336. Arc. Nat. Tom. II. p. 
 19. &.c. Tom. IV. p. 423. &c. 
 
 jo. 
 
 CHAP. 
 
[ 245 ] 
 
 CHAP. XLIV. 
 Of Hairs. 
 
 / ~p H E Hairs of Animals are very diffe- 
 -*• rent in their Appearance before the 
 Micro/cope, and can furniih out a great Va- 
 riety of pleating Obilrvations. Ma lpighi 
 difcovered them to be tubular, that is, com- 
 pofed of a Number of extreamly minute 
 Tubes or Pipes, in his Examination of a 
 Horfe's Main and Tail, and in the Briftles 
 of a Boar. Thefe Tubes were moil diftin- 
 guifhable near the End of the Hairs, where 
 they appeared more open : and he fometimes 
 could reckon above twenty of them. In 
 the Heds;e-Ho2;'s Prickles, which are of the 
 Nature of Hairs, he perceived thefe Tubes 
 very plainly, together with elegant medullary 
 Valves and Cells. 
 
 There are alfo in the Hairs of many Ani- 
 mals, in fome tranfverfe, in others fpiral 
 Lines, fomewhat of a darker Colour run- 
 ning from Bottom to Top in a very pretty 
 Manner. A * Moufe's Hairs are of this 
 Sort, they appear as it were in Joints like 
 the Back-bone, are not fmooth but jagged 
 on the Sides, and terminate in the fharpeft 
 Point imaginable. Hairs taken from a 
 
 J Vii. Arcan. Nat. Tom. III. p. 47. 
 
 R 3 Moufe's 
 
246 Of Hairs. 
 
 Moufe's Belly are leaft opake, and fitteft for 
 the Milcrofcope. 
 
 The Hairs of Men, Horfes, Sheep, 
 HogSj &c. are compofed of fmall, long, tu- 
 bular Fibres, or fmaller Hairs encompaffed 
 with a Rind or Bark; from which Structure 
 a fplit Hair appears like a Stick fhiver'd with 
 beating. They have Roots of different 
 Shapes in different Animals,become lengthen ? d 
 by Propulfion, and are thicker towards the 
 End than at Bottom. 
 
 Hairs of Indian Deer are perforated from 
 Side to Side ; our Englijh ones feem cover 'd 
 with a kind of fcaly Bark. The Whilkers 
 of a Cat, cut tranfverfly, have fomevvhat in 
 the Middle like the Pith of Elder. * The 
 Quills of Porcupines or Hedge-Hogs have 
 alfo a whitim Pith in a ftar-like Form : and 
 a human Hair cut in the fame Manner (hews 
 a Variety of Veffels in very regular Figures. 
 
 Hairs taken from the Head, the Eye- 
 brows, the Noftrils, the Beard, the Hand, 
 and other Parts of the Body appear unlike 
 as well in the Roots as in the Hairs them- 
 felves, and vary as Plants do of the fame 
 Genus, but of different Species. 
 
 * Hook's Microg. p. 157. 
 
 1 CHAP, 
 
[ 2 47 ] 
 
 CHAP. XLV. 
 
 Of the Farina of Flowers. 
 
 np H E Farina ■, or mealy Powder , found 
 -*' on the little pendant Tops of almoft 
 every Flower, is fomewhat fo analagous to 
 the Semen of Animals, that it deferves the 
 iiricteft and moll: attentive Examination. 
 
 This Powder, whole Colour is different in 
 Flowers of different Kinds, was imagined, 
 by former Ages, to be a meer excrement U 
 tious and unneceflary Part of the Plant : but 
 the Micro/cope here alfo has made lurprizing 
 Difcoveries, by (hewing, that all the minute 
 Grains of this Powder are regular, uniform 
 and beautiful little Bodies, conftantly of the 
 fame Figure and Size in Plants or the fame 
 Species, but in different Kinds of Plants as 
 different as the Plants themfelves. 
 
 It was impofTible to obferve this Order 
 and Configuration of the Farince, without 
 concluding, that Providence, which never 
 acts in vain, mult intend a nobler Ufe for 
 Bodies fo regularly formed, than to be difli- 
 pated by the Winds and loft. This Reflecti- 
 on drew on farther Examination ; and farther 
 Examination, by the Help of the fame In- 
 ftrument, foon difcover'd, that this Powder 
 is produced and preferved with the utmoft 
 R 4 Care, 
 
248 Of the Farina of Flowers. 
 Care, in YefTels wonderfully contrived to 
 open and discharge it when it becomes ma- 
 ture : that there is likewife a Pijlil, Seed- 
 Vejfel, or Uterus in the Center of the Flower, 
 ready , to receive the minute Grains of this 
 Powder, as they either fall of themfelves, 
 or are blown out of their little Cells. And 
 Experience, founded on numberlefs Experi- 
 ments, proves, that on this depends entirely 
 the Fertility of the Seed : for if the Farina- 
 Vefjels be cut away before they open and 
 ihed their Powder, the Seed becomes barren 
 and unproductive. 
 
 This Farina is therefore judged to be the 
 Male Seed of Plants, and every litttle Grain 
 of its Powder may poffibly contain in it a 
 minute Plant of the Species whereto it be- 
 longs. ■ It is wonderful to obferve the vari- 
 ous Contrivances Nature employs to prevent 
 this Powder from being unprofitably difper- 
 fed, and to affift its Entrance into the proper 
 Pi/lil, Seed-Vefjel or Uterus prepared for it. 
 The Tulip, for Inftance, which ftands up- 
 right, has its Pijlil fhorter than the Farina- 
 VcfJ'els, that the Powder may fall directly on 
 it: but in the Martagon, which turns down- 
 wards, the Pijlil is longer than the faid 
 Vejfels, and fwells out at its Extremity, to 
 catch the Farina hanging over it, as it 
 meds. 
 
 A Mind 
 
Cf the Farina of Flowers. 249 
 
 A Mind inquiiitive into Nature's hidden 
 Beauties, will find inexpreilible Delight in 
 examining and confidering the endleis Va- 
 riety difcoverable in the Farina of number* 
 lefs vegetable Specie?. In that of the Mai- 
 low, each little Grain appears to be an opake 
 Ball with Prickles hTuing from it on every 
 Side. The Sun-Flower Farina feems com- 
 pofed of flat circular minute Bodies, iliarp- 
 pointed round the Edges ; the middle of 
 them appears transparent, and exhibits fome 
 Refemblance ot the Flower it proceeds from. 
 The Powder of the Tulip is exaclly fhaped 
 like the Seeds of Cucumbers or Melons. The 
 Farina of the Poppy appears like Pearl- Bar- 
 ley, with a Furrow, as in that, reaching from 
 End to End. That of the Lilly is a great 
 deal like the Tulip. 
 
 I'll not anticipate the Pleafure of the Cu- 
 rious, or take up their Time, in defcribing 
 more of thefe Farina, which every Flower 
 they come at prefents to their Examination; 
 but advife them, not to nesled: the Veflels 
 that contain it, for they will find Beauties in 
 them alfo fufficient to reward their Pains. 
 
 Gather your Farina in the midfl: of a 
 Sunfhiny dry Day, when all the Dew is off: 
 be careful not to fqueeze or prefs it, but 
 lhake or elfe gently brum it off with a foft 
 Hajr Pencil upon a piece of clean white Pa- 
 per. 
 
250 Of the Farina of Flowers. 
 
 per. Then take a Tingle Talc or Ifinglafs 
 between your Nippers, and breathing on it, 
 apply it inftantly to the Farina, which the 
 Moifture of your Breath will make adhere to 
 it. If too great a Quantity of Powder 
 feems flicking to your Ifinglafs, gently blow 
 off a little j if there be not enough, breathe on 
 it again, and touch the Farina with it as 
 before. Then put your Glafs into the Hole 
 of a Slider, and apply it to the Microfcope to 
 fee if the little Grains are fpread according to 
 your liking, and when you find they are, 
 cover them cautioufly with another Talc, 
 which faften down with a brafs Wire; but 
 let not the Glaffes prefs hard upon the Fa- 
 rina^ for that will deftroy its true Figure, 
 and reprefent it different from what it is. 
 
 A Collection of the mod remarkable 
 Farina thus preferved muff be a lafting 
 Entertainment to thofe who ftudy Na- 
 ture : to fuch I alfo recommend a diligent 
 Examination of the little Cells that con- 
 tain the Farina , and like wife of the Pijlils 
 or Uteri and other Parts of Generation in 
 Flowers. Let them only begin with the 
 Arch- Angel, or blind Nettle with a white 
 Flower, or even with the common Mallow, 
 and they will difcover Beauties impofTible to 
 be defcribed. And as every other Flower 
 has Organs for the fame Purpofe, though of 
 a different Form and Structure, here are 
 
 Wonders 
 
Of Seeds. 251 
 
 Wonders in abundance for the Microfcope to 
 difcover, and happy the Man who can find 
 moft Leifure to explore thefe Worlds as yet 
 unknown ! 
 
 I (hall add only one Obferyation more be- 
 fore I leave this Head, which is, that as the 
 Animalcules in Semine differ not in Bigneis 
 according to the Size of thofe Animals 
 whence the Semen comes : fo the minute 
 Grains compofing the Farina of Vegetables 
 are not bigger or lefs in Proportion to the 
 Size of the Plants producing them, but are 
 often the direel contrary j as we find by 
 the Farina of the little creeping Mallow, 
 the Globules of which are larger than thofe 
 of the lofty gigantick Sun-flower. 
 
 CHAP. XLVI, 
 
 Of Seeds. 
 
 EACH Seed includes a Plant : that Plant, again, 
 Has other Seeds which other Plants contain: 
 Thofe other Plants have all their Seeds; and, thofe, 
 More Plants, again, fucceflively, inclofe. 
 Thus, ev'ry fingle Berry that we find, 
 Has, really, in itfelf whole Forefts of its Kind. 
 Empire and Wealth one Acorn may difpenfe, 
 By Fleets to fail a thoufand Ages hence: 
 Each Myrtle-Seed includes a thoufand Groves, 
 Where future Bards may warble forth their Loves. 
 
 Sd 
 
252 Of Seeds. 
 
 So Adam's Loins contain'd his large Pufteiity, 
 
 All People that have been, and all that e'er (hall be. 
 
 Amazing Thought ! what Mortal can conceive 
 
 Such wond'rous Smallnefs ! Yet, we mud believe 
 
 What Reafon tells : for Reafon's piercing Eve 
 Difcerns thofe Truths our Senfes can't defcry. 
 
 I hope to be excufed for borrowing the 
 Lines above from a little Poem of my own, 
 called the Univerfe, publimed fome Years 
 ago -, as they contain a Suppofition, which, 
 however chimerical it may appear at firft, 
 will, if duely confidered, be found, per- 
 haps not only poffible, but even highly pro- 
 bable. Malpighi, Leeuwenhoek, 
 Hooke, Grew, and feveral others bear 
 Witnefs, that the Micro/cope has difcover'd 
 minute Plants not only in the larger Seeds, 
 fuch as the Walnut, Chefnut, Acorn, Beech- 
 nut, Seed of the Lime, Cotton -feeds, Peafe, 
 &c. butalfoin the fmaller of Rhadiih, Hemp, 
 Chervil, Scurvy-grafs, Muftard, and multi- 
 tudes of other Seeds. About two Years a- 
 go, I likewile had the Honour to prefent 
 the Diffeclion of a Seed of the Gramen tre- 
 mulum, or trembling Grafs, with an Account 
 thereof to the Royal Society, wherein a per- 
 fect Plant appeared, with its Root, fending 
 forth two Branches, from each of which fe- 
 veral Leaves or Blades of Grafs proceeded. 
 Thus far our Sight amfted by the Micro/cope 
 is able to difcover : and as that Inftrument 
 
 convinces 
 
Of Seeds. 2£% 
 
 convinces us that Nature in her Operations 
 is in no wife confined to our Conceptions of 
 Bignefs, but ads as freely in die minute Fa- 
 brick of a Mite, as in the bulky Compafs of 
 a Whale or Elephant: nay, that (he rather 
 feems to wanton in her Skill, by giving a 
 greater Number of Limbs, and more nume- 
 rous ornaments to the minute Creatures than 
 to the larger ones. When thefe Things, I 
 fay, are feen and reflected on, it is eaiy to 
 conceive the reft. 
 
 Mod Kinds of Seeds muft be prepared, in 
 order to difcover the minute Plants they con- 
 tain, by fteeping them in warm Water till 
 their Coats can be feparated and their femi- 
 nal Leaves opened without Laceration : tho' 
 fome few Sorts may better be differed dry. 
 But Seeds even without any Preparation are 
 exceeding pretty Objects, and afford infinite 
 Varieties of Figure, Colour and Decoration. 
 
 The Seeds of Strawberries rife out of the 
 Pulp of the Fruit, and appear themfelves like 
 Strawberries when viewed. 
 
 Poppy Seeds (and what we call Maw- 
 Seeds, which come from Germany, and are 
 produced bj a Kind of Poppy) in Shape re- 
 femble little Kidneys : but have Furrows or 
 Ridges on their Surfaces curioufly difpofed 
 with regular Sides and Angles. From thefe 
 Seeds a Duft may be fhaken, that looks a- 
 greeable enough when brought before the 
 
 Micro/cope-, 
 
254 Of S ee ds* 
 
 Microfcope % having nearly the fame Appear- 
 ance as the Surfaces of the Seeds, with the 
 Advantage of being tranfparent. This Duft 
 is really the fine Membranes that lay between 
 the Seeds; which, by the Preffure of the 
 Seeds again ft them, have received Marks 
 correfponding to the Ridges or Furrows on 
 the Seeds themfelves. 
 
 Seeds of the leifer Moonwort, of Tobacco, 
 Lettice, Thyme, Chervil, Pariley, and a thou- 
 fand others, afford a delightful Entertainment. 
 
 The Ancients imagined the capillary Plants 
 and many other Kinds to produce no Seeds 
 at all, and their Miflake could never have 
 been rectified by the naked Eye : but the 
 Microfcope has difcovered, that all the feve- 
 ral Species of Fern, Harts-Tongue, Maiden- 
 Hair, &c. are fo far from being barren in 
 this Refpect, that they are amazingly fruit- 
 ful : that the Seed-VefTels are on the Backs 
 of the Leaves, and that the Dull which flies 
 off when we meddle with them, is nothing 
 but their minute Seeds. Thefe Seed-VefTels 
 appear to the naked Eye like a black or 
 brown Scurf on the Backfide of the Leaf ; 
 but, when viewed by the Microfcope^ refem- 
 ble little circular Tubes, divided into many 
 Cells, containing Seeds. When the Seed is 
 ripe, the VefTels fly open with a Spring, and 
 fpirt the Seeds out on every Side, in the 
 Form of Dull: : and if at that Seafon fome 
 of the Leaves are put in a Paper Cone, and 
 
 that 
 
Of Seeds. 255 
 
 that be held to the Ear, the Seed Veflels may 
 be heard to burft with a coniiderable Noife. 
 Some of thefe minute Veflels contain at leaft 
 an Hundred Seeds, invifible to the naked Eye. 
 
 It would be tedious to enumerate the Beau- 
 ties of Seeds, fince every tranfient Obierver 
 muft be fenfible of their great Variety : but 
 I believe I (hall be excufcd, if I take Notice 
 of the Powder or Seed of the Fungus Ful- 
 verulentus or Puff-Bali, which, when crufh'd, 
 feems to the naked Eye like a Smoke or 
 Vapour - y but when examined by one of the 
 greatefl Magnifiers (for elfe it cannot be 
 diftinguifhed) it appears to be infinite Num- 
 bers of little Globules, of an Orange Colour, 
 fomewhat tranfparent, whofe Axis is not a- 
 bove the fiftieth Part of the Diameter of a 
 Hair : lb that a Cube of a Hair's Breadth 
 Diameter would be equal to an hundred and 
 twenty- five thoufand of them. This was 
 the Powder of a Fungus bigger than twoFifts ; 
 but in another Sort the Size of a fmall Apple, 
 the Globules were of a darker Colour, and 
 had each a little Stalk or Tail *. Thefe are, 
 evidently, fo many minute Puff-Balls, fur- 
 nilhed with Stalks or Tails to penetrate eaiily 
 into the Ground : and the Mifchief they do 
 
 * Vtd. PhilofoDh. Tranfaft. Numb. 284. and Dsr ham's 
 Phyf. Theol. p. 418. 
 
 the 
 
256 Of Leaves. 
 
 the Eyes is probably owing to their (harp 
 Stalks that prick and wound them $. 
 
 CHAP. XLVII. 
 
 O/'Leaves. 
 
 / "T -V HE Leaves of Trees or Plants are full 
 -*- of innumerable Veins and Ramifica- 
 tions, that convey the perfpirable Juices to 
 the Pores, for their Difcharge. Whether or 
 no there be any Circulation in them is ftill a 
 Matter of Doubt ; but as their Juices, when 
 let out, immediately break, coagulate and 
 become a ftiff Jelly, it feems probable there 
 may be fome Circulation which prevents the 
 fame Effect in the Veflels. The fudden 
 fhrinking, doling, and opening of Flowers, 
 the railing and finking the Heads of Poppies, 
 &c. the vermicular Motions of the Veins of 
 Plants when expofed to the Air, feem alfo to 
 imply fome what like Senfation. The Mi- 
 crojcobe may perhaps be of Service to difcover 
 much more on thefe Subjects than we yet know. 
 
 \ A Puff-Ball being burft near the Eyes of a Boy of 1 2 
 Years old, by an unlucky Play-fellow, and the Dull thereof 
 flying into them,occafioned fuch Swelling, Inflamm.ition, a.id 
 intenie Pain, with a continual Difcharge of Water, that he 
 could not open them for feveral Days ; and did net recover 
 his Sight in lefs than a Fortnight, tho' all the Remedies that 
 could be thought on were applied. Vid. Jo h . Mu y 's Pi ax. 
 chirur. ration. Obf. I. 
 
 2 Mr. 
 
Of Leaves. 257 
 
 Mr. Lekuwenhoek tearing to Pieces 1 
 Leaf of the Species of Box called Palm a 
 Cereris y that he might examine it the better, 
 computed one Side of it to be farnifhed with 
 an hundred feventy two thoufand and ninety 
 Pores: and as the other Side mud have 
 many, the whole Number of Pores in a tin 
 Leaf of Box will be three hundred forty four 
 thoufand one hunched and eighty. 
 
 The Leaves of Rue feem full of Holes like 
 a Honey-comb ; all the Kinds of St. John's 
 Wort appear likewife ttuck full of Pin-Holes, 
 to the naked Eye; but the Microfcope (hew^ 
 that the Places where thofe Holes feem to be, 
 are really covered with an exceeding thin and 
 white Membrane. 
 
 The Backfide of the Herb Mercury looks 
 as if rough-call: with Silver, and the Ribs full 
 of white round traniparent Balls, like num- 
 berlefs Grapes, fattened by (lender Footftalks. 
 
 A Sage Leaf appears like Rug or Shag, 
 full of Knots taflel'd with iilver Thrums, and 
 embellifhed with fine round cryftal Beads or 
 Pendants fattened by little Footttalks. 
 
 The Backfide of a Rofe Leaf but efpe- 
 cially of Sweet Briar, looks diaper 'd with 
 Silver *. 
 
 Every Body knows that the Leaves of 
 Stinging Nettles are thick fee with fharp 
 
 • Dr.?owift'sAficr0,fcy Qbfervat. 
 
 S Prickles, 
 
2 c3 Of Leaves. 
 
 Prickles, that penetrate the Skin when 
 touch'd, andoccaiion Pain, Heat and Swel- 
 ling : which Symptoms were imagined, for- 
 merly, to enfue from the Prickles being left 
 in the Wounds they make. But the Micro- 
 (cope difcovers fomething much more won- 
 derful in this common Vegetable, and mews 
 that its Prickles are formed and act in the 
 fame Manner as the Stings of living Animals. 
 For every one of them is found to be a rigid 
 hollow Body, terminating in the mod acute 
 Point imaginable, with an Opening near its 
 End. * At the Bottom of this Cavity lies 
 a minute VerTel or Bag, containing a limpid 
 Liquor, which, upon the leaft touching of 
 the Prickle, is fquirted through the little Out- 
 let -, and, if it enters the Skin, produces the 
 Mifchiefs before- mentioned by the Pungency 
 of its Salts. Hence it comes to pafs, that 
 when the Leaves of Nettles are considerably 
 dried by the Heat of the Sun, they fting but 
 very little : whereas fuch as are green and 
 juicy produce violent Pain and Inflammation. 
 But the quite contrary to this would happen, 
 if the Symptoms were only owing to the 
 Breaking of the Prickles in the Flefh: fince, 
 when dry, they muft be more brittle, as well 
 as more rigid, than when they abound with 
 Juice. 
 
 * Hook's Microgr. p. 142. Arc Nat. Tom. I. Par. III. 
 psg. 107. 
 
 %uere. 
 
Of Saks in General. 259 
 
 §>yere. Are there any Valves in the Vef- 
 fels of Vegetables, as in thofe of Animals, 
 to let the Juices pafs, but hinder their Re- 
 turn ? 
 
 CHAP. XLVIII. 
 
 Of Salts in General. 
 
 IT is I think agreed, that all Bodies have 
 their Salts ; from whofe different Confi- 
 gurations and Impreflions many wonderful 
 Changes are erfecteJ both in Solids and Fluids, 
 in things animate and inanimate. Saline 
 Particles ilriking upon the Nerves of Ani- 
 mals excite the Senfations of Tafte and Smell; 
 and as their Forms and Degrees of Impulie 
 are almoil infinitely diverfified, the Senfi- 
 bility of Pain or Pleafure arifing therefrom 
 muft be vary'd almoft infinitely, according 
 to the greater or lets Delicacy of the Organs 
 they ftrike upon.— -It is therefore of great 
 Confequence to difcover what we can about 
 them. 
 
 The Micro/cope (liews, that Vinegar owes 
 its Pungency to multitudes of floating ob- 
 long quadrangular Salts, each of which, ta- 
 pering from its Middle, has two exquifitely 
 
 S 2 iharp 
 
260 Of Salts in General. 
 
 fharp Ends. Thefe Salts being inexpreflibly 
 Minute, can hardly be difcovered, unlefs a 
 Drop or two of Vinegar be expofed for 
 fome Hours to the Air, that the more wa- 
 tery Part may evaporate, before we attempt 
 to view them. 
 
 Their Shape appears, Plate XIV. Fig. I. 
 
 If Crabs Eyes are infufed in Vinegar, 
 after the Effervefcence is over, the Shapes of 
 the Salts will be found quite altered j their 
 fharp Points feem broken off, and they ap- 
 pear in different fquare-like Forms, as at 
 Fig. II. 
 
 In Wines of feveral Kinds the Salts are 
 diftinguifhable, of various Figures, many of 
 them refembling thofe in Vinegar, but with 
 Ends much more obtufe : Some are fhaped 
 like a Boat, fome like a Spindle, others like 
 a Weaver's Shuttle, and others fquare : there 
 are alfo infinite Varieties of other Forms. 
 
 The Salts of Sugar candy 'd are fhewn 
 Fig. III. 
 
 Vegetable Salts are to be extracted by 
 burning the Wood, Stalks, or Leaves of any 
 Tree, or Plant j throwing the Allies into Wa- 
 ter; then filtering, and fetting the Liquor 
 to cryftallize in a cold Place. Their Oils 
 alfo, when examin'd, prefent abundance of 
 Salts. 
 
 The Salts of Minerals or Metals are to be 
 come at, by quenching them, when red hot, 
 in Water, then filtering, evaporating, and 
 cryflallizing. 
 
Of Salts in General. 261 
 
 Pretty Salts for Obfcrvation are, Pot-aih> 
 ILnglifo and RuJJian : Salt of Wormwood* 
 Camphire, Salt of Tartar, Sjlt Armoniac, 
 Salt of Hartfhorn, Salt of Amber, &c\ They 
 mould be examined firft in their dry or 
 cryftallized State, and afterwards diflblved in 
 a very fmall Quantity of fome tranfparent 
 Fluid. 
 
 The Salts found in all Bodies when fe- 
 parated by Fire, fcem as fo many Pegs or 
 Nails*, penetrating their Pores, and fatten- 
 ing their Parts together : but as Pegs or Nails 
 when too large, or too numerous, ferve on- 
 ly to fplit and rend afunder ; Salts, by the 
 fame Means, oftentimes break, feparate and 
 diffolve, inftead of joining and making fail. 
 They indeed are meerly Instruments, and can 
 no more act upon or force themfelves into 
 Bodies, than Nails can without the Stroke 
 of a Hammer; but they are either driven 
 on by the PrelTure of other Bodies, or by 
 the Spring of the Air impelling them. As 
 Salts enter the Pores of all Bodies, Water 
 infinuates between the Particles of Salt : Se- 
 parates or diflblves, and fuftains them in its 
 Interfaces, till by being in a State of Reft they 
 precipitate, and form themfelves into Mattes. 
 By this diflblving Power, Water becomes the 
 
 ♦ ViieSpeBacU dt la Nat. Dial. XXVI. 
 
 S 3 Vehicle 
 
262 Of Salts in Mineral Waters. 
 Vehicle of Salts, and conveys them into the 
 Pores of Bodies, where it leaves them to 
 execute their proper Office. 
 
 Moft forts of Animal and Vegetable Salts 
 are likevvife, probably, diffolved by the Jui- 
 ces of the Stomach, before they enter the 
 Blood, or they would ocean* on great Mif- 
 chiefs : and the Difficulty of difTolving fome 
 mineral Salts, or breaking off their Points in 
 the fame Manner, may be the Reafon of 
 their dreadful Effects. 
 
 CHAP. XLIX. 
 
 Of Salts in Mineral Waters. 
 
 'T"" V H E Microfcope may be of great Service 
 -*■ to determine by ocular Examination, 
 what Kinds of Salts our medicinal Springs 
 are charged with, whence to form a Judg- 
 ment in what Cafes their Waters may be 
 drank to Advantage. 
 
 The four Kinds offo/file Salts, bed known, 
 are, according to Dr. -j- Lister, Vitriol, 
 Alum, Salt-petre, and Sea-Salt : whereto 
 he adds a .fifth, lefs known, though more 
 
 •f Vide Lister de Fontibuj Medicatis Angliae. 
 
 common 
 
/ ',-. 
 
 Fig. 1. 0.2 fo. 
 
 Fia. JLp. 26b. 
 
 O □ 
 
 _? uj.JLi.p-soo. 
 
 -£<</. IK p. 263. 
 
 Fy.V~p.263. Fyr. FT. p.263. 
 
 Fy.ru. 
 
 VJF.P.264. 
 
 4- 3. 
 
 Fuj.FKl.p.26^. Fn/.JCp.aS^, Fiq.-XF. 
 
 .XF.p. 263. 
 
Of Salts in Mineral Wafers. 263 
 
 common than any, viz. Calcarious Salt, or 
 Niter. 
 
 Green Vitriol is produced from the Iron 
 Pyrites. When mature and perfect, its 
 Cryftals are always pointed at each End, 
 and coniift often Planes with unequal Sides: 
 that is, the four middle Planes are Pentagons, 
 and each of the (harp Ends is made up of 
 three triangular Planes, as Plate XIV. Fig. 4.. 
 
 Alum burnt, diffolved in Water, and drain- 
 ed, affords Cryitals whole Top and Bottom 
 are two fexangular Planes, the Sides round 
 which appear compofed of three Planes that 
 are likewife fexangular, and three double 
 quadrangular ones, placed alternately. So 
 that every perfect Cryftal con lifts of eleven 
 Planes, viz. five fexangular, and fix qua- 
 drangular. Fig. V. 
 
 The Water of our Inland Salt-Springs 
 affords Cryftals of an exact cubical Form, 
 one Side or Plane whereof feems to have a 
 particular Clearnefs in the Middle, as if fome 
 Deiiciency were in that Place ; but the other 
 five Sides are white and folic'. See Fig. VI. 
 
 Sal Gem, diffolved, ihoots into the like 
 cubic Cryitals. 
 
 Sea-Water boiled to Drynefs, and its Salt 
 diffolved again in a little Spring Water, crivcs 
 Cryftals alio that are cubical, but remarka- 
 bly different from thofe laft defcribed : for 
 in the Cryftals of Sea-Salt, all the Angl 
 of the Cube are feemingly cut off, and the 
 S 4 Corners 
 
264 Of Salts in Mineral Waters. 
 Corners left triangular: (fee Fig XI. XI.) 
 whereas the Salts of our Inland-Springs 
 have all their Corners fliaro and perfect, as 
 Fig. VI. 
 
 Niter, or Saltpefre,throws itfelf into long 
 (lender iexangular Cryftals, whole Sides are 
 Parallelograms. One End conftantly termi- 
 nates either in a ovramid-like Point, or elfe 
 in a fharp Edge, according to the Pofition 
 of the Sides of two unequal Planes. The 
 other End is always rough, and appears as if 
 broken. Fig. VII. VII. 
 
 The mod general, though leaft noted of 
 ell thzJo//ile Salts amongft us, is a Kind of 
 Wallov c ale arious Niter, or Lime- Salt, which 
 may be collected from the Mortar of anci- 
 ent Walls ; and is, as Dr. Lister fuppofes, 
 what a great Part of the Earth and Mountains 
 confift of*. Its Cryftals are flender and long, 
 the Sides of them four unequal Parallelo- 
 grams : their Point at one End is formed 
 of two Planes with triangular Sides : the 
 other End terminates in two quadrangular 
 
 * We are well affined, that in France, it is the common 
 Pra&ice, for thofe who have the Superintendency of the 
 King's Saltpetre Works, to amafs vaft Quantities of the 
 Mortar and Rubbith taken from old Buildings: whence, by 
 proper Management, they extracl abundance of this calcari- 
 '• ter. And when they have got all they can from it, 
 by ictcingir ;ie together forfome Years, it becomes impreg- 
 nated anew, and affords almoit as much as it did at firft. 
 
 Planes : 
 
Of Salts in Mineral Wat en. 265 
 
 Planes : though both Ends are feldom to be 
 found unbroken.— -Of this Salt fome is feen 
 with five Sides, an. 1 all the other Varieties 
 may be found in it which are (hewn Fig. 
 VIII. 1. a. 3. 4- 5- 6 - 7- 
 
 Unripe, or im perfect Vitriol, is a white 
 Salt, whofe Cryftals are Cubic Rhomboides : 
 as Fig. IX. 
 
 The Cryftals of our Inland Salt-Springs, 
 not yet arrived at Maturity and Perfection, 
 are formed like Fig. X. 
 
 The Particles of each of thefe particular 
 Salts, either in falling one upon another, or 
 uniting on one common Bafe, form them- 
 felves into MafTes, which are invariable, and 
 always of the fame regular Figure : but it 
 is bell: to examine them in the fmalleft Maf- 
 fes, their Shape being there moil perfect and 
 diftindh 
 
 CHAP. L. 
 
 Mifcellaneous Discoveri es and 
 Observations. 
 
 IT has been urg'd by fome in behalf of 
 ■*- fpontaneous Generation, that Worms arc 
 found in the human Bowels, of a Figure 
 feen no where elfe, and therefore that they 
 muil: be generated there, fpontaneoufly, by the 
 
 2 Slime 
 
266 Mifcellancous Difcoveries 
 
 Slime and Heat of the Inteftines: for if they 
 proceed from Parents of their own Kind 
 without the Body, and get into it by Acci- 
 dent, either in the Egg or any other State, 
 where are thofe Parents found ?— This feems 
 a very ftrong Objection ; but the Micro/cope, 
 I believe, can enable us to anfwer it. 
 
 Worms found in the human Body are of 
 three Kinds, viz, the Afcarides, or little, 
 fiort, Jlcnder Maggots, fo nearly refembling 
 a Sort frequently met with in warm moift 
 Places, under rotten Wood, &c. that they 
 may reafonably be fuppofed the fame.— The 
 c feretes,Rotundi, or long round Worms, which 
 are evidently the Species of Earth-worms 
 found commonly in Dunghills and Hot- 
 Beds ; whofe Degree of Warmth is pretty 
 equal to that of the human Bowels. And 
 the Lati, Fafcice, Tape-worms or 'Joint- 
 worms, which are broad, flat, full of Joints, 
 and fometimes of a monflrous Length, ex- 
 tending many Yards along the Inteftines. — 
 This is the Animal faid to be found no where 
 elie : but the Micro/cope has very happily 
 difcover'd Worms of the fame Figure ex- 
 actly, and differing in Size only, in the In- 
 teftines of Eels, fo flxt as not to be removed 
 without great Difficulty, but contracting 
 and dilating themfelves very agreeably* .They 
 
 * Arc. Nat. Tom. IV. p. 367. 
 
 are 
 
and- Obfcrvations. 267 
 
 are of an incredible Length in companion of 
 their Breadth, and when contracted become 
 iix times broader than when extended. There 
 are Tape-Worms likewife in the Bowels of a 
 Turbut y though fhorter than thofe in Eels, 
 with a Head not quite the fame. They are 
 fixed to the Guts by a kind of Hooks which 
 they have in their Mouths, and are not to be 
 got off but by holding the Tail with one 
 Hand, and feparating the Head from the In- 
 teftines with a Needle. 
 
 Having found thefe Worms in the Inteftines 
 of Fi/7:es y let us now conlider how they could 
 get there. And, 'tis probable, they are natu- 
 rally Water-Animals, whofe Eggs or Young 
 Ones getting into the Stomach with the Wa- 
 ter or the Food, become hatch'd or nourifti- 
 ed there. In the fame Manner they may 
 allb be introduced into the Stomach of other 
 Animals : and their Difference of Size in 
 one or the other may arife from the different 
 Degrees of Heat, and the Kindsof Nourifhment 
 they meet with.—Three other Sorts of Worms 
 are allb found in the Inteftines of Eels. Carp 
 are likewife fubject to Worms which make 
 them very lean, and fo is the Trout.— There 
 are two Sorts of white Worms in the Whit- 
 ing \ and the Micro/cope may difcover them 
 perhaps in every other Kind of Fifh ; nor 
 can we wonder at it, when we reflect how 
 liable Fifties muft be to fwallow the Eggs or 
 
 Young 
 
268 Miscellaneous DiJ cover ies 
 
 Young Ones of whatever Infects are Inha- 
 bitants of the Waters. 
 
 2. There are frequently, in the Liver of 
 Sheep, Animalcules fhaped like the Seed of 
 a Gourd, or rather like a fmall thin Myrtle- 
 Leaf with a very fhort Foot-ftalk. Their 
 Colour is whitifh, but numberlefs branching 
 Veflels or minute Canals of a greenifh Yel- 
 low are difperfed every where about them ; 
 and a round Hole or Mouth appears near the 
 Stalk End. Thefe Creatures are found often 
 in the G all-Bladder y and in every Part of 
 the Liver ; where, forming themfelves little 
 Cells, they abide in a Liquor that is feeming- 
 ly Blood mixt with Gall. 
 
 3. In the Heads of * Stags, Worms or 
 Maggots are moft commonly to be met with, 
 lodged in a Cavity under the Tongue, near 
 the Vertebra where the Head joins on to the 
 Neck. Their Shape is partly Cylindrical, 
 being flat underneath, but rounded on the 
 upper Side : in Colour white, with many 
 femi-annular Rings befet with darkifh Hairs. 
 On the Head are a couple of exceeding fmall 
 white Horns, which are thruft out or drawn 
 in like a Snail's ; and under them two mi- 
 
 % Vide Redi deGener. Infect, p. 302.^ 
 * Ibid. p. 307. 
 
 nute 
 
mid Obfervations. 269 
 
 nute Claws, black, hard and (harp, exciting 
 much Itching, and thereby great Uncafinefs. 
 They move along by fixing thefe Claws, and 
 then dragging up their Bodies to them. 
 The End where their Excrements are dif- 
 charged has a little Opening, with two black 
 Spots refembling a Half-Moon. Twenty or 
 thirty are ufually found in one Head, of the 
 Size of very large Maggots. 
 
 4. Like to the foregoing, efpecially to- 
 wards the Tail, but fmaller, lefs vigorous, 
 and not fo hairy, are certain Maggots found 
 in the -f Heads of Sheep. Their white Bo- 
 dies are mark'd acrofs with black Lines, (par- 
 ticularly the largefl of them:) and two black 
 Spots at the Anus, which form a Half- Moon 
 in the Worms of Deer, compofe in thefe a 
 compleat Circle. They abide mod: com- 
 monly in a hollow Part of the Os Frontis 
 nearthe Infertion of the Horns, but are fome- 
 times found even in the Noftrils, and in the 
 Cavities round the Roots of the Horns. 
 Sometimes too they get higher up into the 
 Head, and make the Sheep run mad. They 
 are lefs numerous than thofe in Deer, being 
 feldom more than ten or fifteen. 
 
 5. Early in the Spring Seafon, we fliall fre- 
 quently find flicking to Pales of Wood, efpe- 
 
 Vid. Redi deGencr. Infeft. p. 309. 
 
 cially 
 
270 MifceIlGncous Difcoveries 
 
 daily very old ones, and fometimes to Walls 
 of Brick or Stone, a Sort of little Worm or 
 Maggot, inclofed in a Cafe about the Bignefs 
 of a fmall Barley- Corn. If this Cafe be 
 Viewed with the Micro/cope, it appears cover'd 
 all over with a mod delicate Sort of Mofs, in- 
 termixt with fine Sand or Earth. At the 
 iharpeft End there's a little Hole through 
 which the Excrements are difcharg'd, and 
 at the other a larger Opening, where the 
 Creature puts out its Head, and fattens itfelf 
 to the Pales or Wall. The included Ani- 
 mal is all black, about two Lines of an Inch 
 long, and three quarters of a Line broad. Its 
 Body has feveral Ringlets folding over one 
 another. Its Head is large, flat and polifh'd, 
 refembling Tortoife-fhell, with fome Hairs 
 ifluing from it; and near thereto on each Side 
 are three Legs. The Mouth is large, and 
 in continual Motion, and from it proceeds a 
 flender Thread or Web : the Eyes are black 
 and round. This is a pretty Object, and 
 changes I believe to fome fort of minute Fly, 
 tho' I have not had an Opportunity of mak- 
 ing the Experiment. 
 
 6. Nothing is more common, in the Be- 
 ginning of Summer, than to fee the Leaves 
 of Peaches, Nectarines, and Cherries curled up 
 and blighted : which Leaves on Examination 
 are found cover'd with little Infeffis, fome 
 blackifhi, others green; fome winged, and 
 2 others 
 
and Obfervatiom, 271 
 
 others without Wings. Thefe Creatures 
 bring forth their Young alive and perfect* 
 and if their Bodies be opened, feveral perfect 
 Embryos will be feen therein. — It remains 
 a Doubt, whence, and by what means, thefe 
 Infects are conveyed upon the young fprout- 
 ing Leaves, which, at the fame Time, are 
 always covered with a glutinous and honey- 
 like Moifture : but we may hope, diligent. 
 Obfervations will difcover this Secret to us. 
 Trees in this Condition are vilited by Multi- 
 tudes of Ants ; which hurt not the Trees, 
 as fome erroneoufly conjecture, but do them 
 Service, by devouring this Vermin that in- 
 fers them. 
 
 7. The Ant itfelf is an Object well worth 
 our Notice, being a Creature of a very An- 
 gular Structure. The Head is large, adorned 
 with two pretty Horns, each having twelve 
 Joints. Its Eyes are protuberant and pearl- 
 ed : it has Jaws faw-like or indented, with 
 feven little Teeth that exactly tally, opening 
 Side- ways, and able to gape very wide afun- 
 der ; by the Help whereof it is often feen 
 grafping and tranlporting Bodies of three or 
 four times its own Bulk and Weight. It is 
 naturally divided into the Head, the Breaft, 
 the Belly or Tail : each of thefe Parts joy n- 
 ing to the other by a very flender Ligament. 
 From the Breah>Part, three Legs come forth 
 on either Side. The Tail is armed witfi a 
 
 Sting, 
 
27 2 Mifcellaneous Difcoven'es 
 
 Sting, which the Animal ufes only when 
 provoked; but then a poifonous Liquor is 
 conveyed by it into the Wound, occafion- 
 ing Pain and Swelling. The whole Body 
 is cafed over with a fort of Armour, fo hard 
 as fcarce to be penetrated by a Lancet, and 
 thick fet with mining whitifh BrifHes. The 
 Legs, &c. are alfo cover'd with Hairs, but 
 much fmaller and of a darker Colour. 
 
 Upon opening an Ant-Hill, we (hall fee 
 them carrying in their Mouths and fecuring 
 with great Solicitude fmall whitifh Bodies, 
 ufually call'd their Eggs. Thefe, however, 
 are not Eggs, but Ants in their Aurelia State, 
 each encompafs'd with an Integument of its 
 own fpinning. We might have conjeclur'd 
 this from their Largenefs in Proportion to a 
 perfeff Ant, but the Micro/cope fully proves 
 it, by difcovering to us their real Eggs, of 
 an oblong oval Figure, about the Size of a 
 Grain of Sand * t ninety whereof would not 
 extend the Length of an Inch, nor an hun- 
 dred and feventy be equal in Bignefs to one 
 of thefe Anrelids inclofed in its Cafe. Thefe 
 minute Eggs produce Maggots, which after 
 a Time fpin themfelves Coverings, become 
 Aurelias, and then Ants. The Parents 
 Affection for their Young in the Aurelia 
 State is fo ftrong, that when Danger 
 
 *f Vid. Leeuwbn. Epift. 2d Reg. Soc. 9. Sep. 1687. 
 
 threatens, 
 
end Obfewatlons. 273 
 
 threatens, the\ inftantly run away with them, 
 and willfooner die than leave them. There 
 are fcveral S0 1 s of Ants differing both in Size 
 and Colour; and towards the End of Sum- 
 mer many of.them are feen having four Wings. 
 Thefe, Swammerdam fays, are Males -j-. 
 
 The French Academy has publifh'd a curi- 
 ous Account of Ants, whence I {hall abilract 
 fome few Particulars. Every Ant's Ncft 
 ( ir tells us ) has a ftrait Hole leading into it, 
 abou: the Depth of half an Inch ; which, 
 afterwards, runs flowing downwards to the 
 public k Magazine, where the Grains 
 collect are itored up: and this is a diff ent 
 Place from that where they reft and eat. 
 -- Their Corn being kept under Ground, 
 would ihoot and grow, did they not prevent 
 it by biting out tne Germ en or Bud before 
 they lay it up: but this they constantly do, 
 for if their Corn be examin'd no Bud will 
 be found therein, nor if fowed in the Earth 
 will it ever -vegetate. Was it, however, to 
 lye continually in the Ground, the Moiiture 
 would occaiion it to fwell and rot, and make 
 it unfit for Food. But thefe Inconven encies 
 they find means to remedy by their Vigilance 
 and Labour, in the following Manner. -- 
 
 They gather very fmall Particles of dry 
 Earth, which they bring oui: of their Holes 
 
 f Vid . Swammer. lilji. Generate dis hifecl. p. i8v 
 
 T every 
 
274 Mifcellaneoits Difcoveries 
 
 every Sunfhiny Day, and place them in the 
 Heat. Every one of them brings in her 
 Mouth a Particle of this Earth, lays it by 
 the Hole, and then goes to fetch another : 
 fo that in a Quarter of an Hour a vaft Num- 
 ber of fuch fmall Particles of dryed Earth 
 are heaped round the Hole. Their Corn is 
 laid upon this Earth when under Ground, 
 and covered with the fame. When thefe 
 Particles of Earth are brought out, they fetch 
 out their Corn like wife, and place it round 
 this Earth, making two Heaps about the 
 Hole, one of dry Particles of Earth, and 
 the other of Grains of Corn. Lail of all, 
 they fetch out the Remainder of their dry 
 Earth whereon the Corn was laid. They 
 never go about this Work unlefs the Weather 
 be clear, and the Sun very hot: but when 
 both are favourable they perform it almoft 
 every Day. 
 
 The Author of this Account had found 
 a Neft of Ants in a Box of Earth, Handing 
 out from a Window two Stories high ; 
 whence they made Excursions both upwards 
 to the Top of the Houie, where fome Corn 
 lay in a Garret ; and downwards into a Gar- 
 den, which the Window overlook'd. The 
 Situation of this Neft obliged them to go up 
 or down a great way before they could pof- 
 fihjy meet with any Thing; but he found, 
 notwithstanding, that none of them ever re- 
 turned empty, but brought a Grain of Wheat, 
 
 Rye, 
 
and Obfervations. 2j$ 
 
 Rye, or Oats, a fmall Seed, or even a Particle 
 of dry Earth if nothing elfe could be got. Some 
 travelled to the farther End of the Garden, 
 and, with prodigious Labour, brought heavy 
 Loads from thence. It requirM four Hours, 
 as he learned by frequent Observation, to car- 
 ry a pretty large Grain or Seed from the 
 Middle of the Garden to the Neft: and he 
 computed therefrom, that an Ant works as 
 hard as a Man who lhould carry a heavy 
 Load twelve Miles a Day. 
 
 The Pains thefe Ants took, to carry Grains 
 of Corn up a Wall to the fecond Story, 
 climbing all the Way with their Heads down- 
 ward, muft be exceeding great. Their 
 Wearinefs was thewn,by their frequent Stops 
 at the mod convenient Places; and fome ap- 
 pear'd fo fatigued and fpent they could not 
 reach their Journey's End: in which Cafe, 
 'twas common to fee the ltrongeft A its, 
 which had carried home their Load, come 
 down again and help them. Sometimes 
 they were fo unfortunate to fall down with 
 their Burdens when juft in ir ight of Home : 
 but when this happen'd they feldom loft their 
 
 Corn, but carried it up again. He faw 
 
 one, he fays, of the fmalleft Ants carrying 
 a large Grain of Wheat with incredible 
 Pains. When fhe came to the Box where 
 the Neft was, (lie and her Load together 
 tumbled back to the Ground. Going down 
 to look for her, he found the had recover 'd 
 T 2 the 
 
zy6 Mi/cellaneous Difcoveries 
 
 the Grain, and was ready to climb up again. 
 The fame Misfortune befel her three times ; 
 tut fhe never let go her Hold, nor was dif- 
 couraged ; till at laif, her Strength failing, 
 fhe was forc'd to flop, and another Ant 
 affifred her to carry home her Load to the 
 publick Stock. 
 
 How wonderful is the Sagacity of thefe 
 Infects! How commendable their Care, Di- 
 ligence, and Labour! How generous their 
 Ailiftance of one another for the Service of 
 the Community! How noble their publick 
 Virtue, which is never neglected for the Sake 
 of private Intereft! In all thefe Things they 
 defer ve our Notice and Imitation. — A con- 
 templative Mind will naturally turn its 
 Thoughtsfrom theCondition and Government 
 of Ant-Hills to that of Nations-, and reflect, 
 that Juperi our Beings may poilibly confider 
 Human Kind and all their Solicitudes and 
 Toils, Pride, Vanity, and Ambition, with 
 no more Regard than we do the Concerns of 
 thefe little Creatures. 
 
 8. Among Pinks, Rofcs, and Sun-Flowers, 
 there's to be found, almoft confrantly, a 
 little^ long, nimble Injecl fmaller than a Loufe, 
 feme times creeping, and fometimes leaping. 
 It appears in the Micro/cope bodied like a 
 Wafp, with fix or feven annular Divifions i 
 it has two fair long black and yellow Wingsj 
 two Horns, each rifing from a knobbed 
 
 Roctj 
 
and Obfervatioiv. 277 
 
 Root; two black Eyes, and fix Lea?. 'Tis 
 fo tender the leaft Touch kills it, but a very 
 pretty Object. 
 
 9. A little InfeB is conflantly found in 
 the Froth (or Cuckow-Spit as fome call it) 
 that hangs on the Leaves of Pvofemary, La- 
 vender, &c. It creeps firft, then leap?, and 
 at laft flies. It has fix Feet, with two black- 
 ifh Claws at the End of each ; a long Pro- 
 bofcis to fuck up its Food, two Horns, and 
 a Pair of darkifh red pearled Eyes. The 
 Tail ends in a Stump, but by its annular Di- 
 visions can be thruit out or drawn in at 
 Pleafure. 
 
 1 0. There's a pretty yellow InfeB on Sy- 
 camore Leaves, with fix Legs, running very 
 nimbly. The Eyes are red, prominent and 
 pearled; the Horns are flit, and forked at 
 the Ends. At firft it has no Wings, but 
 near the Shoulders are two little Protuber- 
 ances, whence two long Wings come forth 
 when it turns into a Fly or Locuft. It is 
 hairy towards the Tail. 
 
 1 1 . A fmall white oblong In/eft flicks to 
 the Ribs on the Backfides of Rofe-Tree 
 Leaves, towards the End of Summer, which 
 turns into a little yellow Locuft that fkips 
 about the lame Tree. In both States it is a 
 pretty Object. 
 
 T 3 12. There 
 
2j$ Mifcdlancous Difcoveries 
 
 12. There is alfo a greenifh Grajkopper 
 or Locujiy on Goofeberry- Leaves, Sweet- 
 Bryar, and golden Moufe-Ear, in April 
 and May, with four Leg?, two black Eyes, 
 a pair of curious Horns, and many other 
 Beauties. 
 
 13. In the Water of Ditches there are fre- 
 quently Num*bers of Water-Spiders, not 
 larger than a Grain of Sand j they are very 
 voracious, hunting about continually for 
 Prey: and may be feen by the Micro/cope 
 catching and devouring other minute Animal- 
 cules. Some have eight, fome ten Legs, and 
 Antenna jointed like Equifetum or Horfe- 
 Tail. 
 
 14. Likewife in Handing Waters we may 
 often meet with (lender Eels ox Worms, about 
 the third of an Inch, and fometimes more, 
 in Length. They are full of Joints from 
 End to End zt large Diftances from one 
 another, have a (harp Head like an Eel, a large 
 Mouth, and two fine black Eyes. The Tail 
 terminates in a Tuft of Hairs of a very cu- 
 rious Structure ; the Motions of the Inteilines 
 are feen diftinctlv, and the whole Animal 
 is a delightful Object.— The Blood-red 
 Jointed Worm, very common in ftagnant 
 Waters, is alfo well deferving our Observa- 
 tion. 
 
 15. The 
 

 and Obfervations. 279 
 
 15. The Crane- Ffy> called byALDROVAND 
 Culex maximus > by Swammerdam Tipula 
 terre/iris y and by the common People Fa- 
 ther --long-Legs t affords, in every Part of it, 
 agreeable Subjects of Examination : But the 
 Feet are more particularly furprizing, for upon 
 diffircting them, in a Drop of Water, the 
 fle/hy Fibres contract and diftend, in a Man- 
 ner not to be imagined without feeing it, 
 and continue their Motions three or four Mi- 
 nutes. Mr. Leeuwenhoek found it con- 
 ftantly in the Feet of this Creature, but not 
 in thofe of any other Infect*. The In- 
 teflines are alio very curious, con filling of 
 numberlefs VefTels and Organs, which may 
 be feen as plainly by the Microfcope, as the 
 Bowels of larger Animals can by the 
 naked Eye -f. The Tails both of the Male 
 and Female are of an extraordinary Struc- 
 ture : that of the Female ends in a (harp 
 Point, wherewith (lie perforates the Ground, 
 and depofires her Eggs under the Grafs, in 
 Meadows. 
 
 16. The Multipcs, or Scolopendra, has a 
 very long (lender Body : its Mouth is armed 
 with a pair of (harp Forceps, and in hot 
 Countries (where they are of a large Size) 
 
 * Vid.Arc. Nat.Tom. III.p. 119. f Tom; IV. 351. 
 
 T 4 its 
 
2?o Mifcellaneous Difcoveries 
 
 its Bite is venomous; but our fmaller Ones 
 
 feem not mifchievous. One I examin'd had 
 fifty four Joints, and from every Joint a Leg 
 iiTued on each Side, which, with two others, 
 at the End of the Tail, larger than the reft, 
 made in all one hundred and ten. When 
 the Creature moves along, thefe Legs follow 
 one another very regularly, making a pretty 
 kind of Undulation, not to be defcribed, 
 and giving the Bodv a fwifter Pro°;refTion 
 than one would expect, where fo many Feet 
 take lb many fhort Steps, in turn, one after 
 another. There are feveral Sorts of thefe 
 Infects, different in Shape, and in Number 
 of Legs, which the Curious will be pleafed 
 tQ examine *. 
 
 17. There's an extraordinary Sort of Ca- 
 terpillar, of a middling Size, having four 
 Tufts of yellowiih white Hair, like little 
 Brumes, of an equal Height, Handing up- 
 right on its Back : below thefe, from each 
 Side, iffues a Bunch of dark-colour'd Hairs 
 of different Lengths, the Extremities of 
 which are black. Two more Bunches of 
 the fame Form rife from the Head like 
 Horns, and another ftill from the Top of 
 the Tail. Every Hair in thefe Bunches, 
 
 * Leeuwenhoek fay?, the Indian Millepes has eight 
 Eyes like the Spider. Shtcre. Have Engtijb Ones fo too ? 
 
 when 
 
and Obfervations: 281 
 
 when viewed through the Microfcope, re- 
 fembles a Peacock's Feather, and is a delight- 
 ful Object. The Inquifitive will find abun- 
 dance more Wonders in this amazing Crea- 
 ture, and indeed in moil Sorts of Caterpil- 
 lars. 
 
 18. The Silk-Worm is a Creature every 
 Part whereof, either in the Worm or jF/y- 
 State, deferves our particular Attention: 
 but as both Malpighi and Leeuwen- 
 hoek have examined it with great Skill, 
 and publifh'd their Obfervations with anato- 
 mical explanatory Drawings, I mall refer 
 the Curious to them, and to their own En- 
 quiries ; only advifing fuch as ihall engage in 
 a farther Examination, not to neglect the 
 Skins thefe Animals caft off three Tines 
 before they begin to fpin : for the Eyes, 
 Mouth, Teeth, Ornaments of the Head, 
 and many other Parts may be difcerned bet- 
 ter in the ca/l-off Skins than in the real Ani- 
 mal. A due Obfcrvation of the Changes 
 
 of this Creature, from the Caterpillar to 
 the Nymph , Aurclia, or Chry falls, and thence 
 to the Moth or Butterfly State, will give a 
 general Notion of the Changes all Caterpil- 
 lars undergo, tho' fome little Differences 
 may be in the Manner. Swammerdam 
 fays, the Butterfly, by a judicious Exami- 
 nation, may be traced and difcerned under 
 
 each 
 
2§2 Mifcellaneous Difcoveries 
 
 each of thefe Forms, which are only differ- 
 ent Coverings or Dreffes for it. 
 
 19. The Tail of the Male Silk-Worm be- 
 ing fqueezed, Animalcules were found in the 
 Semen * four times as long as broad : their 
 Backs thicker than their Bellies, like the 
 Shape of a Trout. Their Length was fup- 
 pofed to be about half the Diameter of a 
 
 Hair. This I experienced Myfelf, on the 
 
 8th Day of Augufl, in this prefent Year 1742, 
 when taking a Male Silk-Worm, that was 
 juft then come forth in its Moth-State, and 
 giving its Tail feveral little gentle Squeezes, 
 in about a Minute's Time, a fmall Drop of 
 a brownim white Liquor was fquirted brifk- 
 ly from it on a Talc I held to receive it ; and 
 diluting this with a little Water warmed in 
 my Mouth for that Purpofe, I was very 
 much lurprized and pleas'd to obferve the 
 numberlefs Animalcules it contain'd, fwim- 
 ming about, alive and vigorous. 
 
 N. B. Whoever would make this Experi- 
 ment, muft do it before the Moth has been 
 coupled with the Female ; for nothing is to 
 be got from it afterwards, as I have found by 
 feveral Trials. 
 
 20. The Probofcis of a Butter-fly, which 
 winds round in a fpiral Form, like the Sprjng 
 
 * Vid. Leeuwen. Arc. Nat. Tom. I. P. II. pag. 422. 
 
 of 
 
and Obfervations. 283 
 
 of a Watch, ferves both for Mouth and 
 Tongue, by entering into the Hollows of 
 Flowers, and extracting the Dews and Jui- 
 ces. — The Shape and Structure of it will be 
 found very furprizing. 
 
 21. The Legs and Feet of In feels are 
 wonderful in their Structure and Contrivance, 
 according to their different Circumftancvsand 
 Neceflitics of Life, and afford a pleating 
 Variety of Objects. It is pretty to obferve, 
 not only the iharp hooked Claws, but alfo 
 the fkinny Palms of fomc Flies, &c, which 
 enable them to walk on Glafs and other 
 linocth Surfaces, even with their Bodies hang- 
 ing downwards, by means of the Pre flu re of 
 the Atmofphere : others again have a fort of 
 Spunges, which preferve theirClaws from be- 
 ing broken or blunted by ftrik:ng againil hard 
 Bodies, as the Claws of Cats, &c. are, by 
 ibft flefliy Protuberances at the Bottoms of 
 their Feet. 
 
 22. The Nympb of the CIotbts-Afoth, which 
 (from being often found fcudding among 
 Books and Papers) Mr. Hook calls the iil- 
 ver-colour'd Book-worm, is covered with 
 thin tranfparent Scales, from whofe Surfa- 
 ces a multiplicity of Reflections of Light 
 make the Animal appear in Colour like a 
 fine Pearl. It has fix Legs, runs by Starts 
 and Stops, and has three Horns at the Ex- 
 1 tremity 
 
284 Mifcellaneous D if c overt cs 
 tremity of the Tail. As this Defcription is 
 fufficient to make it known, I mall leave 
 the Curious to examine its Beauties, and not 
 anticipate their Pleafure. Vide Hook's Mi- 
 crog. p. 208. 
 
 23. On the Leaves of Orange-Trees, Fig- 
 Trees, Willows, and many other Trees and 
 Plants, there are various Kinds of minute In- 
 I'eSfs. as vet but Utile known, inclofed in 
 Tubercles or Swellings. 
 
 24. The Eggs of Infefts are remarkable 
 for their different Figure and Colour, and 
 for the particular Regularity and Exactnefs 
 wherewith they are frequently placed. We 
 mall fometimes find a fort cemented round 
 a Twig of the Sloe-Tree or Damfon-Tree, 
 as if fattened there by Art, and rang'd meer- 
 ly for the Sake of Beauty. The Variety of 
 them is inconceivable, and to be fought for 
 as well in the Waters as elfewhere ; as thofe 
 will be convinced who will take the Pains 
 to examine in the Spring, the Water-CrefTes, 
 Brooklime, and other Water- Plants, on the 
 Back of whofe Leaves infinite Numbers of 
 minute Eggs may frequently be difcovered, 
 appearing to the naked Eye only as a Slime. 
 
 25. In Cellars, on the Corks of Bottles, 
 there are three or four Sorts of very furpriz- 
 ing In feels. 
 
 I 26. The 
 
and Obfervations. 285 
 
 26. The Lungs of a Frog, blown up and 
 dry'd, will afTift us to difcover the true Struc- 
 ture of that Bowel. 
 
 27. Cochineal, which comes from New 
 Spain, and is fo valuable for its ufe, in dying 
 Scarlet, Crimfon, and Pur/le : has been a{- 
 ferted, by fome, to be a Seed or Grain, and, 
 "by others, an Infect : but the Micro/cope de- 
 termines thefe Difputes, by (hewing plainly, 
 after fteeping it in Water twenty- four 
 Hours, an oval Body, Scales, Legs, and a 
 pointed Trunk : in fhort, the whole refem- 
 bles our Coic-LaJy. Many Eggs may be dif- 
 covet'd upon opening their Bodies, and if 
 you burn them, let their Afhes (land two or 
 three Days in Wjlter, then filter and evapo- 
 rate, their Salts may be diitinclly feen. 
 
 28. The Feathers of Birds afford variety 
 of Beauty, and differ greatly from one ano- 
 ther, not only in their general Colour and 
 Form, but in the Structure of each particu- 
 lar Part ; as every Body muft be fenfible, 
 who examines thole of the Oftrich, the Pea- 
 cock, the Eagle, the Swan, the Parrot, the 
 Owl, and all die numerous Species of Birds. 
 Their Qi : 11s too deferve our Attention : and 
 our Oblcrvations 6n them will be afTiftcd by 
 readi ig the 36th Obfervation in Mr. Hook's 
 Micrography, p. 168. and alio Mr. Lee u- 
 wenhofk's Experiments, in the 4th Tome 
 of his Writings, p. 323. 
 
286 Mifcellaneous Difcoveries 
 
 29. Mofjes of all Kinds are agreeable Ob- 
 jects, and appear, by die Microfcope, to be 
 as perfect in their Leaves, Flowers and Seeds, 
 as the largeft Plants or Trees. Thole, parti- 
 cularly, that grow on the Rocks and Coafls 
 of the Sea, exhibit amazing Beauties. 
 
 ^o.Spunge is reckon'd a Plant Am mal y 
 and appears compofed of minute VefTels re- 
 sembling Veins and Arteries. 
 
 31. Decay'd Fruits, moift Wood, damp 
 Leather, ftale Bread, and abundance of other 
 Things, contract what we call Mouldinefs ; 
 which the Micro/cope difcovers to be nothing 
 elfe but innumerable minute Plants, bear- 
 ing Leaves, Flowers and Seeds, and increafing 
 in a Manner almoft incredible : for in a ve- 
 ry few Hours the Seeds fpring up, arrive at 
 full Maturity, and bring forth Seed them- 
 klves , fo that a Day produces feveral Ge- 
 nerations of them. There are many Sorts 
 of thefe microfcopical Plants, very different 
 in Size and Appearance : Some of the Mufh- 
 room Kind, Others refembling Bulrumes, 
 and Others again bearing vaft Quantities 
 and great Varieties of Fruit. Other Kinds 
 are likewife found in great Abundance on 
 the Surface of Liquors j when they are what 
 we term Mother y. 
 
 32. 
 
and Obfervations. 287 
 
 32. The Air-Veflels, Sap-Fejels } and Pores 
 diWood are wonderful in their Figure, Num- 
 ber and Dilpofition : as plainly appears by 
 (having off the thinned Slices pomble, length- 
 wife, crofswife, and obliquely, and bringing 
 them to view. Fir and Cork are the rea- 
 died: for this Purpofe : but all other Kinds of 
 Wood, tho' with fomewhat more Trouble, 
 
 may be render'd fit to be examin'd. In a 
 
 piece of Cork, no longer than the eighteenth 
 Part of an Inch, lixty Cells were number'd in 
 a Row ; whence it follows, that one Thou- 
 fand and eighty are in the Length of an 
 Inch : one Million an hundred iixry and fix 
 Thoufand four Hundred in an Inch fquare ; 
 and in a Cubic Inch one Thoufand two 
 Hundred fifty-nine Millions, feven hundred 
 and twelve Thoufand*. 
 
 In the Pith of Trees and Plants, cut fo 
 as to become tranfparent, the VefTels may 
 be difcerned diftinctly. The Pores of Wood 
 may likewife be {ttw advantageoufly in Char- 
 coal and Small- coal, 
 
 33. There are many Sorts of Sand; fome 
 gathered on the Sea Shore, or, on the Shores 
 of Rivers, and others found within Land. 
 The Grams of each Sort differ much in Size, 
 
 * Hook'* Microg. p. 114. 
 
 Form, 
 
288 Mifcellancoiis Discoveries 
 
 Form, and Colour : fome are. opake, others 
 tranfparent : fome have rough Surfaces, and 
 others are quite fmooth *. Thefe Varieties are 
 very agreeable to examine by the Micro/cope, 
 which fhews, in fome of the mining Kinds, 
 Grains having all Numbers of Sides and 
 Angles, and lb finely polifh'd, that no Dia- 
 mond is more ex quiii tely beautiful. On others 
 grotefque Figures, or Reprefentations of 
 Landfcapes, Buildings, Plants, and Animals, 
 at once furprize and pleafe. 
 
 34. In order to examine Diamonds with 
 the greater Exactnefs, Mr. LeeiTwenhoek 
 broke a imall one between two Hammers,and 
 placing the Pieces before his Microjcope, in 
 the Sun-fhine, he faw many fparkling Flames 
 iffue from them, with a continual Corruf- 
 cation, in fome, like a faint Lightning. Then 
 viewing them in the Shade, he obferved, a- 
 mong other pretty Appearances, a little Flame 
 that feem'd to dart from each Particle of 
 the Diamond : and it was a glorious Sight 
 to behold multitudes of fparkling Flames, 
 moft of a bright Fire -Colour, and others 
 greenifb, flail ling faintly and like Lightning 
 at a Diltance. In other Pieces of the 
 
 * Vid. Philafoph. Tranfaftions, Numb. 289. Hook's 
 Microg. p. 80. 
 
 f Vid, Philofoph. Tranf. Numb. 374. 
 
 Diamond 
 
mid Objurations. 2 89 
 
 mond the Lamella or Layers compofing it 
 were very plainly to be diilinguifli'd. 
 
 In ftriking Fire with a Flint and Steel, 
 little Particles of Steel are muck off, and 
 melted into Globules by the Colli fion ; as 
 will be evident upon making the Experiment 
 over a Sheet of white Paper, and viewing 
 what falls into it through the Micro/cope. 
 Mr. Hooke firft: made the Trial, and found 
 that a black Particle, no bigger than a Pin's 
 Point, appeared like a Ball of polilh'd Steel 
 and ftrongly reflected the Image of the Win- 
 dow near which he examined it *. It is alio 
 entertaining enough, to feparate the melted 
 Iron Particles from the Particles of Stone, 
 which fometimes are vitrified ; by means of 
 a Knife that has been touched by a Load- 
 ftone. 
 
 36. Kind Nature has fuppiy'd the Seeds of 
 Dandelion, Thirties, and many other Plants 
 with a Donn, that ferves inftead of Wings 
 to convey them to diliant Places. The Fi- 
 gures of fuch Down, in different Plants, are 
 very different when look'd at through Gl.if- 
 fes : fome appearing plain and fmooth, others 
 rough and thorny, and others again with lit- 
 tle Hooks or Clampers to catch hold of any 
 
 flr.CK's Microg. p. 2:, 44, 46. 
 
 U thin 
 
290 Mlfcellaneous Difcoveries 
 
 thing. Peaches, Quinces, and fome other 
 Fruits have like wife a foft Down, which is 
 worth examining, as well as the Hairs on 
 many Sort of Leaves, Fruits, and Seeds. 
 
 37. There's a very fine Down or Hair call- 
 ed Coinage, or Cow-itch, growing on a Sort 
 of hairy Kidney Bean that comes from the 
 Eaft-Lidies. The Pods, about three Inches 
 long, refemble a French Bean, and are co- 
 vered with this Down or Hair, which is very 
 ftiff for its Bignefs, caufes Pain and In- 
 flammation if rubbed on any Part, and when 
 viewed by a Micro/cope appears like multi- 
 tudes of Needles. 
 
 A Sort of curling Horns, rifing out of the 
 Middle of fome Carnations and Pinks are 
 exceeding pretty Objects. 
 
 38. The Flakes of falling Snow are vari* 
 ous in their Configuration, and extreamly 
 beautiful, if examin'd before they melt ; 
 which may ealily be done by making the 
 Experiment in the open freezing Air. Des- 
 cartes, Dr. Grew, Mr. Hook, Mr. Mor- 
 ton, Dr. Langwith, and others, have 
 edven us feveral of their different Star-like 
 Forms: and Dr. STocKE,of Zealand, has 
 lately communicated to the Royal Society 
 fome new Figures unobferved before. 
 
 The Configuration of the Particles of Dew 
 
 may perhaps be likewife very well worth 
 
 obferving. Plumous 
 
and Obfer r jations. 291 
 
 Plumous Alum, Talcs of different Kinds, 
 Afbeftos, Marcaiites, and all Sorts of Mine- 
 rals and Fofiils, afford a Variety of agreeable 
 and curious Objects. 
 
 iEthiops Mineral, Calomel, Mercurius dul- 
 cis, and all other Mercurial Powders, are 
 found, when examined by the Micro/cope, to 
 be full of minute Globules of crude and un- 
 alter'd Mercury. 
 
 Common Bait diilblved in Water exhibits 
 infinite Numbers of quadrangular Bodies. 
 
 Toads, Frogs, and Newts are * killed by 
 rubbing Salt upon their Backs : Snakes, 
 Vipers, Rattle-fnakes, &c. by drawing thro' 
 their Skin with a Needle a Thread dipped 
 in Oil of Tobacco •, and Mercury is a mortal 
 Poifon to Ants. 
 
 It would be an endlefs Taflc to point out 
 half the Objects fit to be examined by this 
 ufeful and entertaining Inftrument, which 
 fupplies us, as it were, with Eyes, infinitely 
 more penetrating than our own : and diico- 
 vers Wonders to us which wc fhculd be un- 
 able to conceive without it. The foregoing 
 are a few only among thofe that are molt 
 Curious ; but every Creature, every Plant, 
 and Fruit, -and Flower j every Drop of Wa- 
 
 FooK'sMicrog. p. t 44. 
 
 U 2 ter 
 
292 Art and Nature 
 
 ter, and every Particle of Matter, if carefully 
 examin'd, will afford us new Inftruclion and 
 Delight. 
 
 CHAP. LI. 
 
 The Works of Art lend of Nature 
 compared together and coiifiderd. 
 
 EFORE this Treatife is concluded, 
 it will not perhaps be thought unprofi- 
 table, to examine fome of the fineft and 
 moft exquifke Performances of human Art, 
 and compare them with the Productions of 
 Nature ; as fuch a Comparifon muft tend 
 towards humbling the Self-conceit and Pride 
 of Man, by giving him a more reafonable 
 and modeft Opinion of himfelf - y and at the 
 fame Time may in fome Degree conduce to- 
 wards improving his imperfect Conceptions 
 of the Supreme Creator. 
 
 Upon examining the Edge of a very keen 
 Razor by the Microfcope y it appeared as 
 broad as the Back of a pretty thick Knife ; 
 rough, uneven, full of Notches and Fur- 
 rows, and fo far from any thing like Sharp- 
 nefs, that an Initrument as blunt as this feem- 
 ed to be, would not ferve even to cleave 
 Wood f . 
 
 •\ Hook's Microg. 
 
compared and confidered. 293 
 
 An exceeding fmall Needle being alfo ex- 
 amined, the Point thereof appeared above 
 a quarter of an Inch in breadth ; not round, 
 or flat, but irregular, and unequal ; and 
 the Surface, though extreamly fmooth and 
 right to the naked Eye, feemcd full of 
 Ruggednefs, Holes, and Scratches. In ihort, 
 it refembled an Iron Bar out of a Smith's 
 Forge*. 
 
 But the Sting of a Bee viewed through the 
 fame Inftrument, Ihewed every where a Po- 
 lilli mod: amazingly beautiful, without the 
 leafl Flaw, Blemim, or Inequality ; and end- 
 ed in a Point too fine to be difeerned : yet 
 this is only the Cafe or Sheath of Inifru- 
 ments much more cxquifite contained therein, 
 as before defcribed, Page 210. 
 
 A fmall Piece of exceeding fine Lawn, ap- 
 peared, from the large Diitances and Holes 
 between its Threads, fomewhat like a Hurdle, 
 or Lattice, and the Threads themfelves feem- 
 ed coarfer than the Yarn wherewith Ropes 
 are made for Anchors. 
 
 Some Brujfel's Lace, worth five Pounds 
 a Yard, look'd as if it were made of a thick, 
 rough, uneven Hair- Line, entwifted, fatten- 
 ed, or clotted together in a very awkard and 
 unartful Manner. 
 
 * Thil. Tranf. Numb. 324. Spcdacle de la Nat. Eng. 
 Edit. 1 2tno. Vol. I. page X. 
 
 U 3 But 
 
294 Art and Nature 
 
 But a Silkworm s Web being examined, 
 appeared perfectly fmooth and mining, every 
 where equal, and as much finer than any 
 Thread the beft Spinftcr in the World can 
 make, as the fmallelt Twine is finer than the 
 thickeft Cable. A Pod of this Silk being 
 wound off, was found to contain nine hun- 
 dred and thirty Yards : but it is proper to 
 take Notice, that as two Threads are glewed 
 together by the Worm through its whole 
 Length, it makes really double the above 
 Number, or one thouland eight hundred 
 and fixty Yards : which being weighed with 
 the utmoft Exactnefs, were found no hea- 
 vier than two Grains and a half*. What 
 an exquifite Finenefs is here ! and yet, this 
 is nothing when compared with the Web of 
 a fmall Spider, (fee Page 200) or even with 
 the Silk chat iffued from the Mouth of this 
 very W r orm, when but newly hatched from 
 the Egg. 
 
 The fmalleft Dot, Tittle, or Point that 
 can be made with a Pen, appears, when 
 viewed by the Micro/cope, a vaft irregular 
 Spot, rough, jagged, and uneven all about 
 its Edges, and far enough from being truly 
 round. The fmeft and minuted Writing, 
 fuch as the Lord's Prayer in the Compafs 
 of a filver Penny, or other like curious Per- 
 
 Jbid. p. 50. 
 
 formance 
 

 compared and confidered. 295 
 
 formance, done by the mofl: able Mafter, 
 feems, when brought to Examination, as 
 fhapelefs, uncouth and barbarous as if written 
 in Runic Characters. But the little Specks 
 on the Wings or Bodies of Moths, Beetles, 
 Flies, and other Infects, are found when mag- 
 nified, to be moft accurately circular: and 
 all the other Lines and Marks about them, 
 appear regularly and finely drawn, to the ut- 
 nioft Pombility of Exactnefs. 
 
 Dr. Power fays, he law a golden Chain 
 at Tredesc ant's, of three hundred Links, 
 not more than an Inch in Length, fa fined 
 to, and pulled away by a Plea. And I 
 mylelf have feen very lately, near Durham 
 7\ird in the Strand, and have examined with 
 my Microfcope, a Chaife, ( made by one 
 Mr. Boverick, a Watch- maker) having 
 four Wheels, with all the proper Apparatus 
 belonging to them, turning readily on their 
 Axles : together with a Man fitting in the 
 Chaife; all formed of Ivory, and drawn along 
 by a Flea without any feeming Difficulty. I 
 weigh'd it with thegreatefl Care I was able, and 
 found the Chaife, Man, and Flea were 
 barely equal to a fingle Grain. I weighed 
 alio at the fame Time and Place, a Brafs 
 Chain made by the fame Hand, about two 
 Inches long, containing two Hundred Links, 
 with a Hook at one End, and a Padlock and 
 U 4 a Key 
 
296 Art and Nature 
 
 Key at the other ; and found it lefs than the 
 third Part of a Grain. -f- 
 
 We are told, that one Oswald Ner- 
 linger! made a Cup of a Pepper-Corn , 
 which held twelve Hundred other little Cups, 
 all turn'd in Ivory, each of them being gilt 
 on the Edges and (landing upon a'Foot : and 
 that, (o far from being crouded or wanting 
 Room, the Pepper Corn could have held four 
 Hundred more. 
 
 Thefe are fome of the niceft, moll: curi- 
 ous and furprizing Works of Art ; but let 
 us examine any of them with a good Micro- 
 
 jcope, and we ihail immediately be convin- 
 ced, that the utmoft Power of Art is only a 
 Concealment of Deformity, an Impofition 
 
 ■ upon our Want of Sight ; and that our Ad- 
 miration of it arifes from our Ignorance of 
 what it really is. 
 
 This valuable Difcoverer of Truth will 
 prove the moil boaited Performances of Art 
 to be as ill-fhaped, rugged, and uneven, as 
 
 ■f I have feen fince my Writing the above, (made by the 
 fame Artift) a Quadrille-Table with a Drawer in it, an Eating- 
 Table, a Side-Board Table, a Looking-Glafs, twelve Chairs 
 with Skeleton Backs, two Dozen Plates, Six Dimes, a Do- 
 zen Knives and as many Forks, twelve Spoons, two Salts, 
 a Frame and Caflors, together with a Gentleman, Lady, and 
 Footman, all contained in a Cherry-Stone : and not rilling 
 much moie than half of it. 
 
 J Ephem. German. Tom. I. Addend, ad Obferv. 13. 
 
 if 
 
compared and confide red. 297 
 
 if they were hewn with an Ax, or (truck out 
 with a Mallet and Chiflel. It will (hew 
 Bungling, Inequality, and Imperfection in 
 every Part, and that the Whole is difpropor- 
 tionateandmonftrous. Ourfineit Miniature 
 Paintings appear before this Inftrument as 
 meer Dawbings, plaiifer'd on with a Trow- 
 el, and entirely void of Beauty, either in 
 the Drawing, or the Colouring. Our moil 
 mining Varnimes, our fmootheft Polifhings 
 will be found to be meer Roughne fs, full of 
 Gaps and Flaws. 
 
 Thus fink the Works of Art when we be- 
 come enabled to fee what they really are!— 
 But, on the contrary, the nearer we examine, 
 the plainer we diltinguifh, the more we can 
 difcover of the Works of Nature ', even in 
 the leaft and meaneit of her Productions, 
 the more fenuble we muir. be made of the 
 Wildom, Power and Greatnefs of their Au- 
 thor. — - Let us apply the Micro/cope where 
 we will, nothing is to be found but Beauty 
 and Perfection. View we the numbcrlefs 
 Species of Infects that fvvim, creep, or fly 
 around us ; what Proportion, Exactnefs, 
 Uniformity and Symmetry fhall we perceive 
 in all their Organs! what a Profusion of 
 Colouring ! Azure, Green, and Vermilion, 
 Gold, Silver, Pearls, Rubies and Diamonds, 
 Fringe and Embroidery on their Bodies, 
 Wings, Heads, and every other Part ! How 
 
 rich 
 
2<) < 6 Art and Nature 
 
 rich the Glow ! how high the Finifhing ! 
 how inimitable the Poliih we every where 
 behold ! — Search we yet farther, and ex- 
 amine the Animalcules ', many Sorts whereof 
 it would be impoffible for any human Eye 
 unaifiiied to difcern ; thofe breathing Atoms, 
 fo fmall they are almoft all Workmanfhip ! 
 In them too we (hall difcover the fame Or-^ 
 gans of Body, Multiplicity of Parts, Vari- 
 ety of Motions, Diverfity of Figures, and 
 particular Ways of Living as in the larger 
 Animals.— How amazingly curious mud 
 the Internal Structure of thefe Creatures be ! 
 The Heart, the Stomach, the Entrails, and 
 the Brain! How minute and fine the Bones, 
 Joints, Mufcles and Tendons! How exqui- 
 iitely delicate beyond all Conception the Ar- 
 teries, Veins, and Nerves ! What Multitudes 
 of Veffels and Circulations mult be con- 
 tain'd within this narrow Compais! And yet, 
 all have fufficient Room to perform their 
 different Offices, and neither impede nor in- 
 terfere with one another. 
 
 The fame Order, Regularity and Beauty 
 will appear likewife among Vegetables if 
 brought to Examination. Every Stalk, Bud, 
 Flower, or Seed, difplays a Figure, a Pro- 
 portion, a Harmony beyond the Reach of 
 Art. There's not a Weed, not a Mofs, 
 whofe every Leaf does not (hew a Multipli- 
 city of Veffels and Pores difpofed moft curi- 
 oufly for the Conveyance of Juices to fup- 
 2 port 
 
compared and confidered. 299 
 
 port and nourifh it, and which is not adorn'd 
 with innumerable Graces to embelliih it. 
 
 The moll: perfect Works of Art betray a 
 Meannefs, a Poverty, an Inability in the 
 Workman ; but, thofe of Nature plainly 
 prove, the Hand that form'd them was abfo- 
 lute Mailer of the Materials it wrought 
 upon, and had Tools exactly fuitable to its 
 Delign. Every Hair, Feather, or Scale, even 
 of the meaneft Infect, appears rounded, po- 
 lifli'd, and finim'd to the highcit Pitch; and 
 fhews the abundant Riches, Munificence, and 
 Skill of its Maker. 
 
 But fome may pombly enquire, to what 
 Purpofe Providence has beftowed fuch an 
 Expence of Beauty on Creatures lb infigni- 
 ficant: and then cry out, What is all This to 
 us? — My Reply is, that the Beauty and 
 Elegance which adorn them are, evident and 
 convincing Proofs of their not being lb infig- 
 nificantas weprefumptuoufly fuppoie they cxt: 
 for, fuch Beauty muft be given them, either for 
 their own Sake, that they thcmfelves may be 
 delighted with it ; or elfc, for Ours, that we 
 may obferve, in them, the amazing Power 
 and Goodnefs of the Creator. If the former 
 be the Cafe, we muft allow them to 
 be of Confequence in the Account of their 
 Maker, and therefore deferving our Regard ; 
 and if the latter, it is reallv our Duty to take 
 notice of and admire them. But for what- 
 ever 
 
300 Some reafonable RefeBiom o?i 
 ever Reafon God has been pleafed to beftow 
 Exigence on them, and to clothe them with 
 Beauty, what he has judged worthy hirnfelf 
 to create, is not, furely, below us to examine 
 and confider. The lame Hand that form'd 
 the Whale, the Elephant, and the Lion, has 
 likewife made the Loufe, the Gnat, and the 
 Flea. 
 
 CHAP. LII. 
 
 Some reafonable Reflections on Difcoveries 
 made by the Microfcope. 
 
 A Tp H E Ule of the Microfcope will natu- 
 ■* rally lead a thinking Mind to a Conii- 
 deration of Matter, as fafhion'd into different 
 Figures and Sizes, whether Animate or In- 
 animate : It will raife our Reflections from a 
 Mite to a Whale, from a Grain of Sand to 
 the Globe wherein we live, thence to the Sun 
 and Planets j and, perhaps, onwards frill to 
 the fixt Stars and the revolving Orbs they 
 enlighten, where we fliall be loft amongft 
 Suns and Worlds in the Immenflty and Mag- 
 nificence of Nature. 
 
 Our Ideas of Matter, Space, and Dura- 
 tion are meerly comparative, taken from 
 Ourfelves and Things around us, and limited 
 to certain Bounds ; beyond which, if we 
 endeavour to extend them, they become very 
 indiftincT:. The Beginnings and Endings, 
 exceflive Greatnefs or exceflive Littlenefs of 
 2 Things, 
 
Dijtoverhs made by the M'crofcope. 301 
 
 Things, are to us all Perplexity and Confu- 
 fion. 
 
 " Let a Man try to conceive the different 
 " Bulk of an Animal which is twenty, from 
 " another which is an hundred times lcis 
 " than a Mite; or to compare, in his 
 " Thoughts, a Length of aThouiand Dia- 
 " meters of the Earth with that of a xMillion, 
 " and he will quickly find, that he has no 
 u different Meaiures in his Mind adjufted to 
 M fuch extraordinary Degrees of Grandeur 
 " or Minutenefs. The Underftanding, in- 
 " deed, ope"ns an infinite Space on every 
 l< fide of us; but the Imagination, after a 
 " few faint Efforts, is immediately at a (land, 
 " and finds itfelf l wallowed up in the Im- 
 " menfity of the Void that furrounds it. 
 " Our Reafon can purfue a Particle of Mat- 
 <c ter through an infinite Variety of Diviii- 
 " ons, but the Fancy foon lofes Sight of it, 
 cc and feels in itfelf a kind of Chafm, that 
 4< wants to be filled with Matter of a more 
 " lenfible Bulk. We can neither widen, nor 
 " contract the Faculty to the Dimeniions 
 tc of either Extream. The Object is too 
 " big for our Capacity, when we would 
 l< comprehend the Circumference of a 
 " World; and dwindles to Nothing, when 
 " we endeavour after the Idea of an 
 " Atom*" 
 
 * Spc&ator, N°. 420. 
 
 The 
 
302 Some reafonable Reflexions on 
 
 The minute Size of microfcopical Ani- 
 malcules, and the little Space they occupy, 
 when compared with ourfelves and the Room 
 we fill, may poffibly increafe our Pride and 
 Folly, and make us imagine ourfelves of 
 mighty Confequence in the Creation. But 
 if we carry our Thoughts upwards, and 
 compare the Body of a Man to the Bulk of 
 a Mountain, that Mountain to the whole 
 Earth, the Earth to the Circle it defcribes 
 round the Sun, that Circle to the Sphere of 
 the fixt Stars, the Sphere of the fixt Stars to 
 the Circuit of the whole Creation, and the 
 whole Creation itielf to the infinite Space 
 that is every where diffufed about it, we ihall 
 find ourfelves fink to nomine:. — *" Were 
 " the Sun with all its planetary Worlds ut- 
 " terly extinguished and annihilated, they 
 " would no more be miffed in the Grand 
 " Univerfe than a Grain of Sand upon the 
 " Sea-fhore : the Space they poffefs is fo ex- 
 " ceeding little, in companion of the Whole, 
 " that it would fcarce make a Blank in the 
 <c Creation. The Chafm would be almoft 
 ' imperceptible to an Eye that could take in 
 " the whole Compafs of Nature, and pafs 
 " from one End of the Creation to the 
 " other." What then is the mightieft Mo- 
 
 Vide Spe&ator, N°. 565. 
 
 narch 
 
Dijcoveries made by the Microfcope. 303 
 natch that ever lived! What is the whole 
 Race of Man ! 
 
 A Mite upon a Cheeie is as large and 
 considerable, in Proportion, as a Man upon 
 the Earth: the little Iniedts feeding on the 
 Leaves of Peach-Trees and Cherry-Trees, 
 are no ill Representation of Oxen grating 
 in large Paitures: and the minute Animal- 
 cules in a Drop of Water, fwim about with 
 as much Freedom as Whales do in the 
 Ocean: All have equal Room in Propor- 
 tion to their own Bulk. 
 
 The Term or Duration of Life, in different 
 Creatures, is likewife comparatively long or 
 fhort, according to the Number, Quicknefs, 
 or Slownefs of Ideas, prefenting themfelves 
 fucceffively to the Mind. For when the 
 Ideas iucceed one another fwiftly, and ma- 
 ny of them are crouded into a narrow Com- 
 pais, the Time, however mort it may be, 
 will feem long, in Proportion to the Number 
 of Ideas patTing through it : on the contrary, 
 when the Ideas are but few, and follow one 
 another very (lowly, a long Time will appear 
 ihort, in Proportion to their flow Succerhon, 
 and the Smallnefs of their Number. 
 
 u It is evident, fays Mr. Lock, to any 
 u one who will but obferve what poiTes in 
 M his own Mind, that there is a Train of 
 iC Ideas, which conilantly fucceed one ano- 
 
 11 ther 
 
304 Some reafonable Refections on 
 
 " ther in his Under ftanding, as long as he 
 " is awake. Reflection on thefe Appearan- 
 " ces of feveral Ideas one after another in 
 11 our Minds, is what we call Duration. 
 * c For whilft we are thinking, or whilfl 
 <c we receive fucceffively feveral Ideas in 
 ■■ our Minds, we know that we do exifl : 
 " and (o we call the Exigence, or the Con- 
 " tinuation or Exiflence of ourfelves, or 
 " any thing elfe commenfurate to the Suc- 
 " cemon of any Ideas in our Minds, the 
 " Duration of ourfelves, or any fuch other 
 " Thing coexifting with our Thinking" J. 
 
 From thefe Principles it is manifefr, that 
 one Day may appear as a thoufand Years, 
 and a thoufand Years but as one Day : 
 by which means, the Lives of all Crea- 
 tures, for ought we know, may feem to 
 themfelves nearly of the fame Duration. 
 It is at leafl; probable, that fomething like 
 this may really be the Cafe as to the Inha- 
 bitants of this our Earth: for as the fame 
 Functions or Offices of Life, viz. to be born, 
 feek proper Suftenance, increafe in Bulk, ar- 
 rive at full Maturity, propagate the Kind, 
 and die, are equally performed by all j they 
 who perform them in a few Months, Days, 
 
 % Vide Lock on Human Under {landing, Chap. XIV. 
 
 or 
 
Difcoveries made by the Micro fcope. 305 
 
 Or Hours,* may be fnppofed, from the Num- 
 ber and fwift SuccefTion of Ideas fuited to all 
 thefe Purpofes, to live as long, according to 
 
 • Swammerdam has publifhed, in Low Dutch, a curious 
 Account of what he calls the Ephemera n : a Fly which, he 
 telb u>, lives but five Hours. This Infect is found abuut all 
 the Mouths of the Rhine ; and, according to his Drawings 
 and Descriptions. feems to be a Species fomewhat between our 
 May-Fly (bred from the Cadeixi-Worm) and the Lihclla or 
 Dra;a-F/y. It has four Wings, two whereof are lhorter than 
 the other ; a pair of fmall Horns, fix Legs and two very long 
 ftrait Ilairs ifiuing from the Tail. They are feen, he fays, flying 
 near the Surface of theWater, about Midiummer,for three fuc- 
 ceeding Days, but no longer in one Seafon. They eat nothing ; 
 and their only Bufinefs is to generate, and drop their Eggs 
 upon the Water ; which Eggs, finking to the Bottom, pro- 
 duce a Kind of Wormi or Maggots, that foon hollow them- 
 felves Cavities in the Clay, where they abide three Years; 
 growing each Yenr "about an Inch in Length. When the 
 If'orm is come to its full Growth, it rifes to tiie Surfice, about 
 fix o' Clock in an Evening : lays its Eggs, and dies about ten 
 o'CIock the fame Night. 
 
 I'm furprized that Swammerpam fhould fay, the Life 
 of this Creature is no more than five Hours, when his own 
 Account pla nly proves that it really lives three Years : for 
 it is certainly as much alive in the Worm-State, as when af- 
 terwards it becomes a Fly. Truth fhould be every Bodv's 
 
 Purfuit, and for the Sake thereof I have endeavoured to clear 
 up the general Miftake as to this Fly, which is frequently 
 produced, upon Swammerdam's Authority, as the moil 
 remarkable Inftance we know of the Shortncfs ot Life. — But 
 tho' this Infect happens to live much longer than was ima- 
 gined, 1 make no Doubt, there are feme among the number- 
 lefs Species of Beings, whofe natural Lives are as fhort 
 as this was fuppofed to be : fuch too are molt likely to be 
 found amongil the very minute Kinds. For as thofe ex- 
 ccedingl; fmall Plants, invifible to the naked Eye, which com- 
 pofe what we call Moid dine fs, fpring up, bear Fruit,' and dye 
 in a few Hours; we may reafonably fuppcfe, the Lives of 
 fome exceedingly fmall Animals to be of as fhort a Duration . 
 
 X their 
 
306 Reafonable Reflections on 
 their own Thinking, as other Creatures do, 
 where the fame Train of Ideas proceeds more 
 flowly, and takes up many Years. 
 
 As the Microfcope difcovers almoft every 
 Drop of Water, every Blade of Grafs, every 
 Leaf, Flower, and Grain fwarming with Inha- 
 bitants; all of which enjoy not only Life but 
 Happinefs ; a thinking Mind can fcarce for- 
 bear confidering that Part of the Scale of 
 Beings which defcends from himfelf, to the 
 loweft of all fen iitive Creatures, and may 
 confequently be brought under his Exami- 
 nation, -f " Amongft thefe, fome are raifed fo 
 little above dead Matter, that it is difficult 
 to determine whether they live or no : others 
 but one Step higher, have no other Senfe be- 
 fides Feeling and Tafte : fome again, have 
 the additional one of Hearing j others of 
 Smell, and. others of Sight. 
 
 It is wonderful to obferve, by what a gra- 
 dual Progreilion the World of Life advances 
 through a prodigious Variety of Species, be- 
 fore a Creature is formed that is compleat in 
 all its Senfes: and, even amongft thefe, there 
 is fuch a different Degree of Perfection in 
 the Senfes which one Animal enjoys be- 
 yond what appears in another, that tho' the 
 Senfe in different Animals be diflinguifh'd 
 
 f Vide Stella tor. Numb. 519. 
 
 i by 
 
Difcoveries made by the Microfcope. 307 
 
 by the fame common Denomination, it feems 
 almoft of a different Nature. If, after this, 
 we look into the feveral inward Perfections of 
 Cunning and Sagacity, or what we general- 
 ly call Inftinct, we find them riling in the 
 fame Manner, imperceptibly, o;ie above an- 
 other, and receiving additional Improve- 
 ments according to the Species in which they 
 are implanted. 
 
 This Progrefs in Nature is fo very gradual, 
 that the whole Chafm, from a Plant to a 
 Man, is filled up with divers Kinds of Crea- 
 tures, riling one over another by fuch a gen- 
 tle and cafy Afcent, that the little Tranfitions 
 and Deviations from one Species to another 
 are almoft infenfible. And the intermediate 
 Space is fo well hufbanded and managed, that 
 there is fcarcc a Degree of Perception which 
 does not appear in fome one Part of the World 
 of Life, bince then the Scale of Being ad- 
 vances by fuch regular Steps fo high as Man, 
 we may by a Parity of Rcafon fuppoie, that it 
 ftill proceeds gradually upwards thro' number- 
 lefs Orders of Beings of a fuperior Nature to 
 him : as there is an infinitely greater Space 
 and Room for different Degrees of Perfecti- 
 on between the Supreme Being and Man, 
 than between Man and the molt defpica- 
 ble Infect." 
 
 Mr. Lock's Thoughts upon this Subject 
 X 2 are 
 
308 Re a/on able RfjleEiiom on 
 are very curious : " That there mould,. fayS 
 " he, be more Species of intelligent Creatures 
 1 ' above us, than there are of fenfible and 
 " material below us, is probable to me, from 
 <c hence, that in all the vifible and corporeal 
 cc World, we fee no Chafm, no Gaps. All 
 <c quite down from us, the Defcent is by eafy 
 " Steps and a continued Series of Things, that 
 " in each Remove differ very little one from 
 " the other. There are Fifhes that have 
 <l Wings, and are not Strangers to the airy 
 " Region : and there are fome Birds that are 
 <{ Inhabitants of the Water, whofe Blood is 
 " as cold as Filh's, and their Flefh fo like in 
 " Tafle, that the Scrupulous are allowed 
 fc them on Fiih-Days. There are Animals 
 tl fo near a kin to Birds and Beads, that 
 *' they are in the Middle between both. 
 <c Amphibious Animals link the Terref- 
 <( trial and Aquatic together : Seals live 
 " at Sea and at Land, and Porpoifes have 
 <c the warm Blood and Entrails of a Hog : 
 " not to mention what is confidently re- 
 
 ci ported of Mermaids or Sea- Men.— 
 
 tc There are fome Brutes that feem to have 
 tC as much Knowledge and Reafon as fome 
 <c that are called Men ; and the Animal and 
 " Vegetable Kingdoms are fo nearly joined, 
 " that if you will take the loweit of one 
 " and the higheft of the other, there will 
 fcarce be perceived any great Difference 
 
 €{ between 
 
 4< 
 
Djfcoveries made by the Micro fcope. 309 
 
 " between them. And fo on till we come 
 " to the lowed and the mod inbrganical 
 
 ic Parts of Matter, we mall find every where 
 " that the feveral Species are linked together, 
 " and differ but in almofi infallible Degrees. 
 i( And when we confider the infinite Power 
 " and Wifdom of the Maker, we have Rea- 
 tc foil to think, that it is fuitable to the 
 " magnificent Harmony of the Univerfe, 
 <f and the great Defign and infinite Good- 
 <f nefs of the Architect, that the Species of 
 " Creatures, mould alfo, by gentle Degrees, 
 €i afcend upwards from us towards his infi- 
 •■ nite Perfection j as we fee they gradually 
 <c defcend from us downwards. Which if 
 "it be probable, we have Reafon then to 
 u be perfwaded, that there are far more 
 " Species of Creatures above us than there 
 lt are beneath : we being in Degree of Per- 
 tf fecl:ion much more remote from the infi- 
 t£ nite Being of God, than we are from the 
 •* loweft State of Being, or that which ap- 
 " proaches nearefl to Nothing". 
 
 Every Creature is confined to a certain 
 Meafure of Space, and its Obfervations (tinted 
 to a certain Number of Objects: but fome 
 move and act in a Sphere of a wider Cir- 
 cumference than that of others, according 
 as they rife above one another in the Scale 
 of Exiftencc. This Earth is the Spot ap- 
 pointed 
 
 X 3 
 
3 i o Reafo?iable Reflections on 
 pointed for Man to dwell and act upon : he 
 Hands foremoft of all the Creatures here, and 
 links together Intelligences and Brutes. The 
 Sphere of his bodily Action is limited, con- 
 fined, and narrow ; but that of his Mind is 
 vafr,and extenfive beyond the Bounds of Mat- 
 ter. Form'd for the Enjoyment of intellec- 
 tual Plea fares, 'his Happinefs aiifes from his 
 Knowledge j and his Knowledge increafes in 
 Proportion as he difcovers and contemplates 
 the Variety, Order, Beauty, and Perfection 
 of the Works of Nature : whatever, there- 
 fore, can aflift him in extending his Obfer- 
 vations, is to be valued, as in the fame Degree 
 conducive to his Happinefs. 
 
 What we know at prefent, even of things 
 the moft near and familiar to us, is fo little 
 in comparifon of what we know not, that 
 there remains a boundlefs Scope for our En- 
 quiries and Difcoveries j and every Step we 
 take, ferves to enlarge our Capacities, and 
 o-lve us ftill more noble and juft Ideas of the 
 Power, Wifdom, and Goodnefs of the Deity. 
 
 The Univerfe is fo full of Wonders, that 
 perhaps Eternity alone can be fuffkient to 
 furvey and admire them all : perhaps, too, 
 this delightful Employment may be one great 
 Part of the Felicity of the Bleffed. When 
 the Soul (hall become diverted of Flefh, the 
 Pleafures of Senfe can be no more : and if, by 
 
 a 
 
Difcoveries made by the Microfcope. 311 
 
 a continued Habit, any Longings after them 
 (hall hang about it, fucli Longings muft create 
 a proportionable Degree of Wretchednefs, as 
 they can never pombly be gratified. But if 
 its principal Delight has been in the Con- 
 templation of the Beauties of the Crea- 
 tion, and the Adoration of their Almighty 
 Author, it foars, when difembodied, into the 
 celeftial Regions, duely prepared for the full 
 Enjoyment of intellectual Happinefs. 
 
 To Thee, eternal felf-exifting Creator 
 of the Universe ! whofe Will is Nature's 
 Law ! Omnifcienr, Omniprefent, All-Boun- 
 tiful and Gracious ! To Thee be paid, by 
 all thy Creatures, Thankfgiving and 
 Adoration, till Time fhall be no more ! 
 
 INDEX. 
 
INDEX- 
 
 A. 
 
 Page 
 
 Anemone (Sea) or Mnjhrcom, an extraordinary Animal, 98 
 
 Animalcules in Fluid?, ■ 68 
 
 how produced ■ ibid. 
 
 not if covered - 69 
 
 forts in Pepper-Water ~~ 72 
 
 how kill'd by different Mixtures — — — 75 
 
 forts in Hay-Water 76 
 
 fome Univerfal ibid. 
 
 Eel-Jike Kinds *■ 79 
 
 — —in Vinegar — — Hi /• 
 
 how affected by Heat and Cold 80 
 
 __ -inPafte — — 81 
 
 in Rain and other Waters ■ 83 278 
 
 ; caufe the Colours of Waters — 84 
 
 obferv'd in fevera) Infufions by Monf. Jcblot 87 
 
 why not always the fame ibid. 
 
 at the Roots of Duck- Weed 91 
 
 in Leaden Pipes and Gutters »■ ibid. 
 
 two forts in Ditches defcribed 93 
 
 a very extraordinary Kind — — 94 
 
 ■ its Young how produced ■ ■ ibid. 
 
 as defcribed by Mr. Leewwenhoek ibid. 
 
 — by an Englijh Gentleman 95 
 
 by Mr. Buffbn 96 
 
 by one at Geneva 97 
 
 Reflections thereon 10 1 
 
 AnimcLules in the Teeth -— ■- ■ ■ 167 
 
 how to deftroy i63 
 
 in itchy Puftules . . 169 
 
 in the Light of Oyflers — — 241 
 
 A> i nalcules in Semine Mafculino, how to view 58 159 
 
 when fn ft discover' d — — 153 
 
 their general Appearance . ibid. 
 
 tl-.eir Numbers computed - 149 155 
 
 their wonderful Minutenefs ■ 163 
 
 Reflections on their Size — 165 
 
 l Animalcules 
 
INDEX. 
 
 Animalcules in Semine Mafculino of a Frog, p. 154. 
 
 of a Cod-Fifli ■ 155 
 
 of a Pike ■ 155? 
 
 of a Cock « 159 
 
 of a Dog ' 1 60 
 
 •of a Hare ibid. 
 
 of a Rabbet • 1 6 1 
 
 of a Ram ■ ibid. 
 
 of a Man ■ .... 163 
 
 of a Spider ■ • ■ 16c 
 
 of a Dormoufc 166 
 
 of anOyiter 166 239 
 
 of the Mulclc Fifh . 243 
 
 of a Silkworm 166 282 
 
 of a Dragon- Fly 166 
 
 of a common Fly ibid. 
 
 of a Flea ibid. 
 
 of a Gnat - — . 206 
 
 Vide Infedls. 
 
 Animalcules in none of the Animal Juices but only the Semen 
 
 166 
 
 Animah (living) to examine , rj rj 
 
 how admirable their Structure ■ 2 q8 
 
 Ants dcfcribcd 271 
 
 their Eggs and Aurelia? 272 
 
 their Sagacity, Forecaft, and Induilry 273 
 Reflections thereon ■ _ 
 
 Antenna of Infects : vide Horns. 
 
 276 
 
 Area, or Portion of an Object fcen 48 
 
 A>t compar'd with Nature ■ 292 297 290 
 
 Arteries and Feins, how diuinguifh'd 124. 
 
 Authors Defign in Writing : vid. Introduce, and r 1 
 
 B. 
 
 Balances of In feds 
 
 their Ufe 
 
 2 3? 
 'bid. 
 
 Fat (Obfervations on it) . ,-j 
 
 Beauty, why bellowed on Infe<5l«, Is'c. 200 
 
 Bee, vide Sting. 
 
 Bignefs, meerly comparative . , ~ j 
 
 Blood (Circulation of) ro view . rn \ X j lzo 
 
 lamination of by the Microfcope i OZ JI2 
 
 Account of as fo examin'd . | , 
 
 Strudure and Compofition of its Globules ibid 
 
 Size of the Globules __ , - 
 
 Bkod, 
 
INDEX. 
 
 Blood, how eafily diforder'd .. p. 10S 
 
 Mixtures with it in the Veins, their Effects 1 10 
 
 — — when extracted ■ no 114 
 
 its Colour whence - ■ ■■■■■ 116 
 Vid. Circulation. 
 
 JBloodlefs Animals, a Miftake ■ ■ ■ 1 29 
 
 Boajls (ridiculous ones) as toMicrofcopes — — 64 
 
 Bones, their Structure ■ ■ ■ ■■ 143 
 
 foft at firft ■ — — 1 44 
 
 Manner of viewing them ~ 145 
 
 Book-Worm (or Clothes-Moth) .—» 282 
 
 Box for preferving opake Objedls •■ 6 1 
 
 Brujh or Hair-Pencil, its Uie 1 1 
 
 Bug a curious Object — - — — 130 
 
 Butterfiy, its Probofcis — — — — 282 
 
 C. 
 
 Camera olfcura Microfcope > ■ ■ 22 
 
 Cautions in viewing Objects ■ . 62 
 
 Cell to confine living Objefts , - 19 
 
 Chain of Gold, its Finenefs . . 295 
 
 of Bnfs . . _ jhiJ. 
 Circulation of the Blood to view -.-. — n~ 120 
 
 between a Frog's Toes ■ 1 2 1 
 
 in an Eel - ■- . 1^2 
 
 in a Flounder ______ . fad. 
 
 in a Fifh's Tail . ■ ■ . 123 
 
 how numerous in a Human Body 1 25 
 
 in a Newt __-> 126 
 
 in a Tadpole — — . 127 
 
 in a Mufcle Fifh ----- _-_-_, ibid. 
 
 in the Legs of Crabs ■ 1 28 
 
 in Shrimps — — . ___ j 2 a 
 
 in the Legs of Spiders . ■ 1 30 
 
 in Punices or Bugs — — — . ibid. 
 
 in a Bat ■ 131 
 
 in a Frog by the Solar Microfcope, very curious 134 
 
 its Appearance near the Time of Death 1 36 
 
 Cochineal examin'd ____, 2 8c 
 
 Collection of tranfparent Objects to make — — . 56 
 
 of opake Objeds 60 
 
 proper Cafe for them --____ 61 
 
 Colours of Objects how to judge of . 5? 63 
 
 Cone to intercept the Rays of Light, itsUfe 1855 
 
 Cork its numerous Pores ■_>-- ■ . ,, 287 
 Corn-Beetle, vid. Weevil. 
 
 Coinage, 
 
INDEX. 
 
 Cowagi, or Cow-itch, what ■ ■ ■■ 
 
 Crane-Fly, very wonderful ■ 
 
 Cube, why confider'd as if magnified — 
 
 Cups, 1 200 in a Pepper-Corn « ■< ■ 
 
 D. 
 
 Dew recommended to be examin'd — 
 
 Diamonds examin'd by the Microfcope 
 Double Reflecting Microfcope defcribed 
 Down of Thirties, &c. 
 Drawings of Objefts to take 
 
 Duckweed, ftrange Animalcules at its Roots 
 
 Dunghill-Water lull of Animalcules 
 
 Dying, the Appearance of the Blood then 
 
 E. 
 
 - 290 
 *79 
 
 3i 3* 
 296 
 
 290 
 
 288 
 
 16 
 
 289 
 
 2 5 47 
 - 91 
 
 ' 85 
 136 
 
 Eel, Way to examin it • 
 
 its Scales . ■■ 
 
 Eel-like kinds of Animalcules . 
 
 in Vinegar ■ ■ 
 
 Experiments on them — 
 
 in Pafte 
 
 Way to preferve and examine 
 
 their Appearance by the Solar Microfcope 
 
 Eggs of Infcdls __ 
 
 Elephant compnr'd with a Mite, vid. Introduc. 
 
 Ephemeron defcribed . , 
 
 Miilake about it reclify'd _, 
 
 122 
 
 238 
 78 278 
 
 79 
 80 
 81 
 82 
 ibid. 
 284 
 
 305 
 ibid. 
 
 Farina of Flowers defcribed 
 
 its Uieand what it is 
 its Beauties 
 
 way to preferve and examine it 
 
 its Veffels curious ■ 
 
 Obfervations on it • 
 
 Feathers, delightful Objefts , 
 
 Feelers of Infefts, vid. Horns 
 
 Fibres (mufcular or flelfn ) their Appearance 
 
 their Structure . 
 
 in an Ox, Whale, and Moufe 
 way of viewing them — — . 
 
 in a Crane- Fly, very curious 
 
 Fih, how to place in a Glafs Tube . 
 
 2 47 
 248 
 249 
 250 
 ibid. 
 251 
 285 
 
 135 14* 
 '39 
 140 
 141 
 
 - 279 
 
 — »3 
 
 Fijb. 
 
INDEX. 
 
 Eifc-Van 
 Flea defcribed 
 
 Manner of Change from the Egg 
 
 its Coitus 
 
 Diffeclion of _ 
 
 its furprizing Strength and Agility 
 Fluids how to prepare and examine — — 
 
 Fly defcribed — .— 
 
 it? .Trunk 
 
 Diffeftion of 
 
 Manner of Produ&ion — 
 
 Focus what ■ ■ 
 
 forceps or Plyers, their Ufe — 
 Frog how to place in a Glafs Tube 
 
 Apparatus for viewing the Circulation in it 
 Mefentery thereof a curioui Object 
 
 its Lungs 
 
 *9 
 
 191 
 193 
 
 194 
 
 «95 
 ibid. 
 
 S8 
 219 
 
 ibid. 
 220 
 
 ibid. 
 
 4 
 10 
 
 13 
 133 
 13? 
 
 285 
 
 Gad Bee, vide Ox Fly 
 
 Generation equivocal, contrary to Reafon ■ 
 
 Manner of 
 
 Analogous between Animals and Vegetables 
 
 Glafs flat, its Effect 
 
 convex, its EffecT: 
 
 its magnifying Power explain' d — 
 
 how to find its magnifying Power ■ 
 
 concave, its Effect ■■ 
 
 Glafs Slips of different Colours, their Ufe - ■ 
 
 Glaffes mull be fuited to the Objects 
 
 Glafs-Tube, its Ufe — — — — 
 
 Globules of the Blood, how form'd « ■■ 
 
 their Size . — -« 1 
 
 their Appearance in Sicknefs 
 
 in Fifties anJ aquatic Animils — — 
 how affected by Heat and Cold — — 
 
 Vide Circulation. 
 Globule or Drop of Glafs, its Inconvenience — — 
 not ufed by Mr. Leeu^iuenboek - 
 
 Gnat, its Manner of Production 68 
 
 Defcription of it — — 
 
 its Form in the Water — 
 
 its Wings and Horns . 
 
 its Piercer defcribed 
 
 its Spawn — — 
 
 207 
 148 
 150 
 »5» 
 
 ■j 
 J 
 
 46 
 
 - 3* 
 
 33 
 
 - 5 
 
 60 
 
 53 
 11 ; 9 
 103 
 01 132 
 108 
 131 
 ibid. 
 
 6 
 
 7 
 
 88 207 
 
 203 
 
 - 88 
 203 
 20.4 
 206 
 
 Grain 
 
I N D E X. 
 
 Grain of Sand, how to be underftood as a Meafure p. k\ 
 
 Growth of Animals and Vegetables, what iqo 
 
 H. 
 
 Hairs of different Creatures 24c 
 
 tneir Structure « ■ ibid. 
 
 their Variety 246 
 
 of a Caterpillar, very beautiful 280 
 
 Hay Water to make . -6 
 
 when ready for Examination . ibid. 
 
 the Animalcules therein ■■ ibid. 
 
 Ihahh, wherein it confiits 106 116 
 
 how impair'd io- 
 
 how probably it may be reftored 109 
 
 Contrivance of Providence to preferve it 119 
 
 Heart (Pulfation of) ■ 17 7 
 
 in a Bee ^ 
 
 * fy <, .... 
 
 a Graff hopper ( ' "" tb,a - 
 
 \ 
 
 a Lady-Bird 
 
 in a Snail . . 13S 217 2 ^8 
 
 inaLoufe 138 l8o 
 
 Horns of Infefts, their Ufe 2 xi 
 
 their different Beauty . , ,■ ibid. 
 I. 
 
 Ignis Fat 11 us ■ — 2 ±z 
 
 Infujwis of Vegetables produce Animalcules -5 
 
 obferv'd by Monf. Joblot - g_ 
 
 why productive, a Supposition g6 
 
 why not always the fame . g 7 
 
 In/efts how to difleel — __ -g 
 
 fitteft to (hew the Circulation and internal Motion 
 
 • 1 " "7 '4 2 
 
 *n the Liver of Sheep _ ' 2 6i 
 
 in the Heads of Sheep - . 2 ^ Q 
 
 in the Heads of Deer - 2 ^g 
 
 on Pales and Walls . . 2 „ 
 
 on Leaves ■ ^ 27I 
 
 among Pinks. Roles, ©V. 276 
 
 in Cuckow-fpit O 
 
 on Sycamore Leaves > ■ 2 -"r 
 
 on the Ribs of Rofe. Leaves 3 
 
 on Goofeberry-Leaves , 278 
 
 Legs and Feet examin'd . 283 
 
 on Orange, Fig and Willow-Leavss 284: 
 
 Infers, 
 
r- 
 
 INDEX. 
 
 Jnfetls, their Eggs beautiful 7 
 
 on Corks of Bottles \ P- "4 
 
 Itch, a Diftemper occafion'd by Animalcules 169 
 
 defcribed 170 
 
 how cured ■ 171 
 
 Jurin (Dr.) his Way of meafuring Objeds 45 
 
 L. 
 
 Lace (fine Bruflels) examin'd ■ 293 
 
 Leaden Pipes or Gutters, Animalcules there defcribed 92 
 
 Leaves, whether have any Circulation 256 
 
 their Pores how numerous ■■ 257 
 
 of Rue 
 
 St. John's Wort 
 
 Mercury J> _ ibid. 
 
 Sage 
 • Rofe and Sweet Briar 
 
 Fern . 
 
 Stinging-Nettle (/ery wonderful) . 258 
 
 like the Stings of Animals . ibid. 
 
 Lens what 2 
 
 Leeuwenhoek (Mr.) the Structure of his Microfcopes 8 
 
 Liberkhun (Dr.) his folar and opake Microfcopes 21 
 
 Life, in what Manner long or fhort — — - 303 305 
 
 its Progreffion in different Creatures ■ 306 
 
 Light muft be fuited to the Objecl - ■■ 54 
 
 its different Effedl ibid. 
 
 of a Candle beft for fome Things 55 
 
 of the Sun, not elegible — — ibid. 
 
 Loufe f common^ defcribed — — 177 
 
 its Manner of Feeding . — 179 
 
 a Sting in the Male — ■ — 1 80 
 
 its Increafe how numerous . 1 8 1 
 
 way to diffeft it 182 
 
 (Crab) 182 
 
 a general Name for the Vermin of Creatures 183 184 
 on the Beetle "J 
 
 lZ' S \ — ' 8 3 
 
 Spider J 
 
 Humble Bee 1 ,0. 
 
 Flea \ l84 
 
 (Kinds of) Pi&ur'd by Seignior Rett ibid. 
 
 Wood- Loufe — — — 185 
 
 M. 
 
INDEX. 
 
 M. 
 
 Magnifjini Power of GlafTes in the fingle Microfcope p. - 1 
 
 explain' d . ■ ■ ■- — - : 
 
 how to find and calculate - 33 
 
 Table of ■ ■ ■ . 
 
 in the folar Microfcope 37 
 
 in the Double Microfcope — - — — 39 
 
 Man, his propereft Employment vide Introduc. 
 
 his Capacity for Knowledge 310 
 
 whence his eternal Happincfs may poffibly arife 3 1 1 
 
 Matter, Confederations thereon 300 
 
 our Ideas of it imperfect 301 
 
 Mercury unalter'd in feveral Mercurial Medicines 291 
 
 Microfcopt what I 
 
 by whom and when invented ■ j 
 
 Single 2 7 
 
 Double ■ — — ibid. 
 their different Effects and Advantages 2 7 49 
 
 LeeuivcnboeA's, its Structure g 
 
 Wllforis fingle Pocket . 9 
 
 with a Speculum • 14. 
 
 Standard for its GlafTes propofed 37 
 
 Double Reflecting 16 
 
 Solar, or Camera Obfcura . 22 
 
 its Advantages ■ . 25 
 
 for opake Objects 26 
 
 Standard for its Glaflcs propofed 37 
 
 its Advantages 27 
 
 how to ufe it i • 29 
 
 ufeful alfo for tranfparent Objects 30 
 
 wherein it properly can affilt us 49 
 
 why fometimes neglected 51 
 
 how ferviceable in the Practice of Phvfick 107 
 Minutenefs of Animals, &"c. wonderful : vid. In trod. 163 298 
 
 Reflections on it 302 
 
 Mtfentery of a Frog, extrcamly curious . 1 3- 
 
 Mitts defcribed 186 
 
 their Coit and lime of Hatching ■ 188 
 
 their Eggs ■ 188 
 
 compared with a Pigeon's . ibid. 
 
 their Voracioufnefs and Manner of Eating ibid. 
 
 how to defiroy ■ — 1 gn 
 
 Sorts of defcribed .... ■ — ibid. 
 
 wandering , — — g<jo 
 
 very tenacious of Life — — — ibid. 
 
 Mojet, 
 
I N D E X. 
 
 MoJ/ej, exceedingly beautiful Objects p. 286 
 
 Motion ietn by Microfcopes, how to be regarded — 63 
 
 Mouldinefs, feveral Species of Minute Plants 247 
 
 Multipes or Scolopendra, very curious . 279' 
 
 Mufcles of the Abdomen of a Frog 1 5 5 
 
 Mufdt-Yijh a fine Object 128 242 
 
 its Eggs and Embryo-Mufcles -■ ■ 243 
 
 how numerous ibid. 
 
 the Beard, its Ufe — 244 
 
 N. 
 
 Nature's Operations amazing . — 253 
 
 the Perfection of exemplify 'd — — 297 
 
 compared with the Works of Art 292 297 
 
 the Study of them Man's nobleft Employment : vid. 
 
 Introd. and . 300 
 
 Needle, its Point examin'd - 293 
 
 Ner-ves, their Structure and Appearance 146 
 
 not elaftic . — 147 
 
 Newf, a fine Object 1 26 
 
 Globules of its Blood larger than in mod Animals ibid. 
 how to kill i . 291 
 
 O. 
 
 Objects, how feen thro' a Single M'Crofcope 2 
 
 how thro' a Double one ibid. 
 
 how thro' a flat Glafs ■ ' ■ 3 
 
 how thro' a Convex — = — 4 
 
 appear large to fhort-fighted People 5 
 
 their real Size to find 40 158 
 
 Mr. Leeu~L>:enboeJi i Way 41 
 
 Mr. Hook's Way * 44 
 
 Dr. Jurins Way 4? 
 
 Dr. Martins V, ay 46 
 
 Dr. Smith's Way 47 
 
 Area cr Portion of — — 48 
 
 Kinds proper for the Microfcope 50 
 
 what not proper 49 
 
 Directions how to examine — 52 
 
 to be view'd in every Light 54 
 
 their Shadcw only feen by the folar Microfcope 55 
 
 how to prepare and apply - 56 
 
 to make a Collection of ; ." 56 60 
 
 Csutions in the viewing of — 62 
 
 tailed — — — — 291 
 
 Old 
 
INDEX. 
 
 Old People, their Manner of Sight p. 5 
 
 Opake Obje&s (Microfcope for) vid. Micrcfcope 
 
 to prepare and preferve 60 
 
 Opium, how it afts on the Blood 114 
 
 Ox-Fly defcribed 22 6 
 
 its Manner of Production 207 
 
 Oyjlers, Animalcules in their Liquor 239 
 
 in theirSemen 1 /..y 
 
 Embryos J 
 
 their Size and Number 240 
 
 Light on them — > 241 
 
 Pajie full of minute Eels • °i 
 way to preferve therrt ■■ ibid. 
 
 People, old, or wort- lighted, their Cafe 4 
 
 Pepper Water, vid. Animalcules. 
 
 Perijlaltic Motion vifible 138 179 195 219 
 
 Poifes of Infects, vid. Balances 
 
 Polype, a wonderful Animalcule fo called 97 
 
 Pores of the Skin 1 74 
 
 way to view them ibid. & 176 
 
 how numerous 1 • ■ 17? 
 
 of Wood, their Numbers . . - . ■■» 287 
 
 Pulfe beating, vide Heart, 
 
 R. 
 
 i?«/«-Water, its Animalcules » . 83 
 
 Razor, its Edge examin'd — — ■■■ 293 
 
 Sal Volatile oleofum, its Effects on the Blood —— I ! 5 
 
 Salts to prepare and examine 58 
 
 their general Effects 259 
 
 in Vinegar • ■ ■ ■ — — — ibid. 
 
 how chang'd by Crabs Eyes - 260 
 
 in Wines, Vegetables, and Metals — — ibid. 
 
 Sorts to be examin'd ... 261 
 
 their good and ill Effects ___— . Hid. 
 
 (Sorts of) in Mineral- Waters 262 
 
 of Vitriol ■ 263 
 
 ——unripe 1 — — 265 
 
 Y Salts 
 
INDEX. 
 
 Salts, . ■ .. ...of Alum 
 
 from Salt Springs 
 Sal Gem 
 from Sea Water 
 Niter 
 Okarious Niter 
 
 Sand (Grain of) how underflood as a Meafure 
 
 Sands fine Objefts for the Microfcope ~- 
 
 Scale of Beings confider'd ■ 
 
 Scales on the Human Skin 
 
 of Fifhes 
 
 how numerous 
 Way to view them 
 
 fhew their Age •— — 
 
 how to prepare - 
 Scoloper.dra, vide Multipes. 
 Scorpion^ vide Sting. 
 
 Seeds not proportion'd. to the Size of their Plants 
 
 include minute Plants . . 
 
 of the Gramen tremulum 
 
 p. Z63 
 
 204- 
 
 4» 
 
 288 
 
 307 
 172 
 
 173 
 ibid. 
 
 237 
 238 
 ibid. 
 
 to prepare 
 
 of Strawberries 
 Poppy- 
 Fern 
 Puff-Bail 
 
 -how hurtful to the Eves 
 
 Semen Mafculinum, vide Animalcules.' 
 
 Serpents Minute . 1 — — ________ 
 
 Shaife, &c. drawn by a Flea - , 
 
 Sheep (Worms in) vide Infects. 
 
 Sight, its Difference how occafion'd _____ 
 common Standard of . 
 
 Silk-n.vorm _ __ 
 
 Semen thereof cwimin'd •__, 
 
 Length and Finenefb of its Silk 
 
 Sliders what --. 
 
 their great Ufe , , 
 
 to prepare a Set of prop- 
 
 Snail, a curious Animal . 
 
 Manner of Production and Growth 
 
 Srone found therein — 
 
 Sncw, its Configuration curious — — . 
 
 Solar or Camera obfeura Microfcope : vide Microfcope. 
 
 Spider, its Eyes . ,. .-— , 
 
 .65 
 
 252 
 
 - ibid. 
 
 253 
 
 ibid. 
 
 2 54 
 255 
 
 256 
 
 78 
 295 
 
 4 5 
 32 
 
 281 
 ■ 282 
 
 294 
 10 
 
 56 
 
 57 
 
 217 
 
 - 218 
 ibid. 
 290 
 
 196 
 
 Sj>ider t 
 
INDEX. 
 
 Spider, Us Weapons p. 197 
 
 poilonous Liquor how inftilled ■ 199 
 
 Web how fine 200 
 
 Eggs 201 
 
 White Field , ibid. 
 
 Hunting 7 
 
 Shepherd > Spider 202 
 
 Red \ 
 
 Water Spider 278 
 
 Stags, Worms in their Heads . 263 
 
 Star Fim 97 
 
 or Stella Arborefcens (ending forth many Thousand 
 
 Branches 100 
 
 Steel (Particles of) melted by linking Fire 289 
 
 'Sting, how diilinguifhed — — 209 
 
 of a Bee defcrib'd . 210 293 
 
 v. y to view it 21 1 
 
 its povfonous fuice — 21 2 
 
 of a Scorpion dclcribed ibid. 
 
 its poyfonou^ fuice - 213 
 
 furprizing Effect of 2 i 4. 
 
 Surjhine^ a bad Light lor Objects ■ jr 
 
 T. 
 
 Table of the Powers of fingle G'afies — — 3 - 
 
 Tittle made with a Pen exainin'd 204 
 
 Tranjparency how fometimes acquir'd 129 
 
 Truth only to be (ought for 6 \ 
 
 Tube (Glafs) its Ufe "' j , 
 
 (capillary; its great Ufe 59 
 
 V. 
 
 Vegetables (Infufions of J produce Animalcules 70 76 86 87 
 
 Veins, formed to pi. feivc Health . 119 
 
 Vinegar (Animalcules therein) vide Animalcules. 
 
 it? Salts examined 2 -q 
 
 Viper, its Teeth and Poyion 2I - 
 
 W- 
 
 Hater, full of Life : vide Animalcules. 90 
 
 . /or Corn-Beetle defcribed . 221 
 
 its Manner of Production 22a 
 
 Wbalt t its prodigious Size IO i 
 
 Wheel. 
 
INDEX. 
 
 Wheel-Work in the Heads of fome Animalcules p. <)i 
 
 Wilforis Pocket Microfcope : vide Microfccpe. 
 
 Wings of Jnfefls ■ . ,. 232 
 
 their Variety — — — — — 233 
 
 their Motion — — — — ■ . ibid, 
 
 their fine Feathers — — 234 
 
 way to view them •• ■ - — — ibid 
 
 Wolf defcribed — — • ■ ■ 1 — 223 
 
 its Increafe . 224 
 
 way to deftroy — 225 
 
 Wood, its Air-VefTels, Sap-Veffels, Pores, &c. — 287 
 
 Wood Loufe — 185 
 
 Worms in Human Bowels — — ■ 265 
 
 their Kinde — — — — 266 
 
 how probably introduced ■ ibid. 
 
 in Fifties . 267 
 
 Blood-red, jointed — — 278 
 
 FINIS. 
 
A Plate of the Solar Microscope being 
 
 given , in the Second Edition of the Micro- 
 scope made easy, it was found neceflary 
 to draw up a new Defcription of that In- 
 Jlrument, conformable thereto, and in the 
 following Manner, 
 
 Page 22. Chap. VI. 
 
 THIS Microfcope depends on the Sun-fhine, and muft 
 be made ufe of in a darkened Chamber, as its Name 
 implies. 
 
 It is compofed of a Tube, a Looking-glafs, a convex Lens, 
 and W i l son's fingle Pocket Microfcope before defcribed, p. 9. 
 
 The Sun's Rays beingdire&ed by the Looking-glafs through 
 the Tube upon the Object, the Image or Piclure of the Objecl 
 is thrown, diftinftly and beautifully, upon a Screen of white 
 Paper, or a white Linen Sheet, placed at foaie Diftance to 
 receive the fame ; and may be magnified, to a Size beyond 
 the Imagination of thofe who have not feen it : for the far- 
 ther off the Screen is removed, the larger will the Objeft ap- 
 pear ; infomuch, that a Loufe may be magnified to the 
 Length of five or fix Feet, or even a great deal more ; but it 
 is indeed, more diftinft, when not enlarged to above half that 
 Size. 
 
 The Apparatus for this Purpofe, as represented in the Plate 
 annexed, is as follows. 
 
 A. a Cquare wooden Frame, through which two long 
 
 Screws pafs, and, aflifted by a Couple of Nuts 1. 1. fallen it 
 
 firmly to a Window-mutter, wherein a Hole is made for its 
 
 * Reception .; 
 
Reception ; the two Nuts being let into the Shutter, and made 
 fctft thereto. 
 
 A circular Hole is made in the middle of this Frame, to 
 receive a Piece of Wood of a circular Figure, B, vvhofe Edge, 
 that projects a little beyond the Frame, compofes a lhallow 
 Groove 2, wherein runs a Cat-gut 3 ; which by twilling 
 round, and then crofling over a Brafs Pulley, 4, (the Handle 
 whereof, 5, paries through the Frame) affords an eafy Mo- 
 tion for turning round the circular Piece of Wood B, with all 
 the Parts thereto affixt. 
 
 C is a Brafs Tube covered with Seal-Skin, which fcrewing 
 into the Middle of the circular Piece of Wood, becomes a 
 Cafe for the uncovered Brafs Tube D, to be drawn backwards 
 or forwards in. 
 
 E a fmaller Tube of about one Inch in Length, cemented 
 to the End of the larger Tube D. 
 
 F is another fhort Brafs Tube, made to Aide over the above- 
 defcribed Tube E. To the End hereof the Microfcope mult 
 be fcrewed when we come to ufe it. 
 
 5, A convex Lens, whofe Foces is about twelve Inches, 
 defigned to colled the Sun's Rays, and throw them more 
 flrongly upon the Objett. 
 
 G, a Looking-glals of an oblong Figure, fet in a wooden 
 Frame, faftened by Hinges to the circular Piece of Wood B, 
 and turning about therewith, by means of the above-mention> 
 ed Cat-gut. 
 
 H, a jointed Wire, partly Brafs and partly Iron : the 
 Brafs Part whereof, which is flat 6, being fattened to the 
 Looking glafs, and the Iron Part, which is round 7, patting 
 through the wooden Frame, enable the Obferver (by putting 
 it backwards or forward:-) to elevate or decline the Glafs ac- 
 cording to the Sun's Altitude. 
 
 8, a Brafs Ring at the End of the jointed Wire, whereby to 
 manage it with the greater Eafe. 
 
 N. B. The Extremities of the Cat-gut are faftened to a 
 Brafs Pin, by turning of which it may be braced up, if at 
 any time it becomes too flack. This Pin lying behind could 
 not be fhewn in the Pi&ure. 
 
 When this Microfcope is employed, the Room muft be ren- 
 dered as dark as poflible : For on the Darknefs of the Room, 
 and the Brightnefs of the Sunfhine, depend the Sharpnefs and 
 Perfection of your Image. Then putting the Looking glafs 
 G through the Hole in your Window-fhutter, fallen the fquare 
 Frame A to the faid Shutter by its two Screws and Nuts, r. 1. 
 
 This 
 
This done, adjuft your Looking-glafs to the Elevation and 
 Situation of the Sun, by means of the jointed Wire H. toge- 
 ther with the Cat-gut and Pulley 3.4. For the firft of thefe 
 raifing or lowering the Glafs, and the other inclining it to 
 either Side, there refults a twofold Motion, which may eafily 
 be fo managed as to bring the Glafs to a right Pofition ; that 
 is, to make it reflect the Sun's Rays directly through the Lens 
 5, upon the Paper Screen, and form thereon a Spot of Light 
 exactly round *. 
 
 As foon as this appears, fcrew the Tube C into the Brafs 
 Collar provided for it in the Middle of your Woodwork, 
 taking care not to alter your Looking-glafs : then fcrewing 
 the Magnifier you chufe to employ to the End of your Mi- 
 crofcope, in the ufual Manner, take away the Lens at the 
 other End thereof, and place a Slider, containing the Object 
 to be examined, between the thin Brafs Plates, as in the other 
 Ways of ufing the Microfcope. 
 
 Things being thus prepared, fcrew the Body of your Mi- 
 crofcope to the fhort Brafs Tube F, which flip over the fmall 
 End E of the Tube D, and pull out the faid Tube D lefs 
 or more, as your Object is capable of enduring the Sun's Heat. 
 Dead Objects may be brought within about an Inch of the 
 Focus of the convex Lens, 5 ; but the Diitance muft beihort- 
 ened for living Creatures, or they will foon be killed. 
 
 If the Light falls not exactly right, you may eafily, by a 
 gentle Motion of the jointed Wire and Pulley, direct it 
 through the Axis of the microfcopic Lens. 
 
 The fhort Tube F, which your Microfcope is fcrewed to, 
 enables you, by Aiding it backwards or forwards on the other 
 Tube E, to bring your Objects to their true focal Diftance ; 
 which will be known by the Sharpnefs and Clearnefs of their 
 Appearance : they may alfo be turned round by the fame 
 Means, without being in the leaft difordered. 
 
 The Magnifiers moil ufeful in the Solar Microfcope are, in 
 general, the fourth, fifth, or fixth. 
 
 * Though obtaining a perfectly circular Spot of Light upon the Screen 
 before you apply the Microfcope, is a certain Proof that your Looking- 
 glafs is adjufted right, that Proof muft not always be expected : for the 
 Sun is fo low in Winter, that if it fhines in a direct Line againft the 
 Window, it cannot then afford a Spot of Light directly round. But if it 
 be on either Side of you, a round Spot may be obtained even in De ■ 
 ctmbtr. 
 
 * 7 Mention 
 
One from its Parent, and kept it in a Glafs alone ; notwith- 
 ilanding which it bred very plentifully. And that no Copula- 
 tion might poffibly be performed between the young ones them- 
 selves, he has cut them off, one by one, as they fprouted out, 
 and has kept each of them alone, and that for feven fucceffive 
 Generations ; but without finding any Difference as to their 
 Increafe. He has likewife feen a Polype bring forth young ones, 
 and thofe again producing others, before the firft has been Se- 
 parated from its Parent. They multiply more or lefs in pro- 
 portion to their Feeding, and the Warmnefs of the Weather. 
 
 But the moft amazing Part of Mr. Trembley's Account, 
 is, what he tells us, concerning his Operations on thefe Crea- 
 tures. If one of them be cut in two, tranfverfly, the Fore- 
 Part, which contains the Head, Mouth and Arms, lengthens 
 itfelf, creeps, and eats, on the very fame Day. The Tail- 
 Part forms a Head and Mouth at the wounded End, and 
 fhoots forth Arms, more or lefs fpeedily as the Heat is favour- 
 able. In Summer they will be fhot out in 24 Hours, and the 
 new Head perfected in a few Days. 
 
 Cut a Polype where or into what Parts you pleafe, tranf- 
 verfly, each Part becomes a compleat Polype. But being too 
 fmall an Animal to admit of being divided into many Parts at 
 once, he firft cut one into four Quarters, and let them grow ; 
 then divided each Quarter, and proceeded, fubdividing, till 
 he obtained fifty out of one : and has ftill by him feveral Pieces 
 of the fame Polype thus cut above a Year ago, which have pro- 
 duced Numbers of young ones. 
 
 If a Polype be cut the long Way, through the Head, Sto- 
 mach and Body, each Part is half a Pipe, with half a Head, 
 half a Mouth, and fome of the Arms at one of its Ends. The 
 Edges of thefe halfPipes gradually round themfelves, and unite, 
 beginning at the Tail End ; and the half Mouth and half Sto- 
 mach of each becomes compleat. All this he has feen done 
 in lefs than an Hour, and the two Polypes thus formed differed 
 nothing from whole ones, but in having fewer Arms ; which 
 Defeft a few Days Supplied. A Polype has been cut, length- 
 ways, between 7 and 8 in the Morning, and between 2 
 and 3 in the Afternoon, each Part has devoured a Worm as 
 long as itfelf. 
 
 Cutting a Polype, lengthways, through the Head and Body, 
 but not quite through the Tail, in a fliort time there will be 
 two perfeft Heads and Bodies with but one Tail : which 
 Heads and Bodies, may, foon after, be again divided in like 
 manner : and thus, Mr. Tr e m bley fays, he has produced a 
 Polype with feven Heads and Bodies conjoined by one Tail. 
 Thefe feven Heads being cut off* at once., feven others grew 
 
 in 
 
in their Head j and each of the feven Heads (o cut off, put- 
 ting forth a new Body, became a compleat Polype. 
 
 He cut a Polype, tranfverfly, afunder, and putting the two 
 Parts clofe together, they united where they had been cut. 
 The Creature eat the next Day, is grown fince, and has mul- 
 tiplied. The Fore-Part of one Polype united in the fame man- 
 ner to the Hind -Part of another. This compound Animal 
 eat likewife the next Day, and has fince produced young ones 
 from each of the Parts that formed it. But thefe two Experi- 
 ments don't always fucceed. 
 
 'Twas faid before, that the Body of a Polype is a fort of hol- 
 low Gut or Tube : this he has found means to turn infide out, 
 as one may turn a Stocking ; and has feveral, at prefent, by 
 him, whofe Infides remain to be their Outftdes ; notwithltand- 
 ing which, they eat, grow, and multiply, as if nothing had 
 been done to 'em. He has repeated all thefe Experiments 
 feveral times, with the utmoft Precaution, Affiduity and At- 
 tention ; and might appeal, he fays, to the Quality and 
 Number of the Perfons who have feen them made by him, 
 as well as of thofe who have made the fame themfelves. He 
 adds, that in the Hiftory of the Po/y/c, which he has in 
 Hand, all the Methods and Contrivances ufed by him in his 
 Obfervations will be defcribed, but even before its Publica- 
 tion he is ready and willing to communicate any Information 
 that may enable others to perform the like. 
 
 Mr. Reaumur, Fellow of the Royal Academy of Sci- 
 ences in France, declares (in the Preface to the fixth Volume 
 of his Hijlory of Infeds jult publiihed at Paris) that he has re- 
 peated all Mr. Trembley's Experiments, not only by him- 
 felf, but with Mr. Jussieu and feveral others of the faid 
 Academy, and found them fucceed as they had done in Hoi' 
 land, of which he gives a general andfuccinft Account. When 
 firft he faw two compleat Animals forming themfelves from 
 the Parts of one Polype cut afunder, he knew not, he fays, 
 how to believe his Eyes ; and he can't yet behold it, without 
 new Amazement, tho' he has feen it an hundred and an hun- 
 dred times. He adds, that the Curious in France foon began 
 to try if other Creatures might not be found with the fame 
 extraordinary Faculty. That Mr. Bon net foon difcovered 
 a (lender Water- Worm about one Inch and half long that had 
 the fame Property ; and Mr. Lyon ett found another above 
 three Inches long, and the Thicknefs of the treble String of a 
 Violin, which being cut into thirty or forty Parts afforded the 
 fame Phenomena. 
 
 Mr. 
 
Mr. Reaumur imagining that fome Sea Productions, 
 whofe Shape fomewhat refembles this frtfh Water Polype, fuch 
 as the Urtic? marina and Star-Fijb, might have the like Fa- 
 culties, engaged Mr. Gu ettard and Mr. Ju s s i e u to make 
 Variety of Experiments on the Coafts ofPoifiou and Normandy. 
 They broke and cut Star-Fijh into feveral Parts, and had the 
 Pleaiure to fee the feveral Parts continue alive, and their 
 Wounds cicatrize and heal ; and tho' they could not flay long 
 enough in the Country to fee new Parts (hoot forth inftead of 
 thofe cut away ; Mr. Gerrard de Villars has feen the 
 XJrtica on the Coafts near Recbelle reproduce all the Parts cut 
 off, and the Star-Fijb putting forth new Radii in the Room of 
 thofe they had been deprived of. When the Fifhermen faw 
 Mr. Jussieu tearing and cutting one of thofe Animals in 
 Pieces, they told him, 'twas Labour in vain, he could not kill 
 it : Experience having taught them what Men of Learning had 
 never fo much as heard of. Mr. Reaumur and Mr. Bon- 
 k et found alfo fome forts of Earth- Worms, which being cut in 
 two, each half had all its Deficiencies reproduced after fome 
 Months. Many indeed died, but as fome fucceeded, the 
 Mifcarriages muft be imputed to want of Care, and not to the 
 want of fuch an Ability in thefe Animals. 
 
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