;t^;iiaa«MSn't«H£E£iU3IMe:^ftB 
 
BOUGHT WITH THE INCOME 
 FROM THE 
 
 SAGE ENDOWMENT FUND 
 
 THE GIFT OF 
 ,(.. I89X 
 
Cornell University Library 
 
 3 1924 031 222 031 
 olin.anx 
 
The original of tliis book is in 
 tlie Cornell University Library. 
 
 There are no known copyright restrictions in 
 the United States on the use of the text. 
 
 http://www.archive.org/details/cu31924031222031 
 
NEW CENTURY SERIES 
 
 OF 
 
 ANATOMY PHYSIOLOaY AND HYGIENE 
 
 BY 
 
 HENRY F. HEWES, A.B., M.D. (Haevaed) 
 
 Teacher in Physiological aud. Clinical Chemistry, 
 Harvard Uuiversity Medical School, Boston. 
 
 WINFIELD S. HALL, PH.D., M.D. (Leipsig) 
 
 Professor of Physiology, 
 Northwestern University Medical School, Chicago. 
 
NEW CENTURY SERIES 
 OF ANATOMY PHYSIOLOGY AND HYGIENE 
 
 1. OBAii Lesson Book in Htgiene. 
 
 For Primary Teachers. 
 
 2. The New Century Primer op Hygiene. 
 
 First Book for PupiLs Use 
 
 3. Intermediate Physiology and Hygiene. 
 
 For Fifth- and. Sixth-Year Pupils, or Corresponding Classes in 
 Ungraded Schools. 
 
 4. Elementary Anatomy Physiology and Hygiene. 
 
 For Higher Grammar Grades. 
 
 5. Anatomy Physiology and Hygiene. 
 
 For High Schools. 
 
N£W CENTURY SERIES 
 OF ANATOMY PHYSIOLOGY AND HYGIENE 
 
 ELEMENTARY ANATOMY 
 PHYSIOLOGY AND HYGIENE 
 
 FOR 
 
 HIGHER GRAMMAR GRADES 
 
 BT 
 
 WINFIELD S. |IALL, Ph.D., M.D. (leipsic) 
 
 PROFESSOR OF PHYSIOLOGY, NORTHWESTERN UNIVERSITY MEDICAL 
 SCHOOL, CHICAGO 
 
 NEW YORK •:• CINCINNATI •:• CHICAGO 
 
 AMERICAN BOOK COMPANY 
 
6 PREFACE 
 
 largely experimental and practical, of the phj-siology of 
 a growing plant. Through this means one can best show 
 the interdependence of plant and animal kingdoms, and 
 the unity and harmony of nature. 
 
 Attention is called to the experiments suggested and 
 described in the text. The appliances and material sug- 
 gested are readily procurable; and the experiments de- 
 scribed may easily be performed by any bright and 
 energetic teacher. Taught in this way physiology be- 
 comes a living and intensely interesting science. The 
 problems given for solution by the pupils will tend to fix 
 indelibly the hygienic principles involved in them. 
 
 Especial attention is called to the lessons on Domestic 
 Economy. This work has never failed to arouse the 
 interest not only of the pupils, but of parents also, their 
 feeling being that the school work in physiology is being 
 made practical as life itself is and must be. This chapter 
 and that on plant physiology is the "wprk of Mrs. Winfield 
 S. Hall. 
 
 The author is indebted to Professor Wilson of Colum- 
 bia University, to Professor Piersol of the University 
 of Pennsylvania, and to Professor Williams of the Uni- 
 versity of Buffalo for several valuably figures. Acknowl- 
 edgment is due also to Messrs. Lea Brothers, Philadelphia, 
 for permission to reproduce several figures from the 
 author's Text-hook of Physiology, of which they are the 
 publishers. 
 
 WINFIELD S. HALL. 
 
 eHicAGO, June, 1900. 
 
CONTENTS 
 GENERAL PHYSIOLOGY 
 
 CHAPTER PAGE 
 
 I. Plant Physiology — How the Plant lives and grows . 11 
 II, The Cells, Tissues, and Organs of the Body ... 27 
 
 III. The Nervous System — How the Different Organs are 
 
 made to work in Harmony .... .46 
 
 IV. Narcotics — Their Nature, their Classes, and their Gen- 
 
 eral Action upon the System 58 
 
 SPECIAL PHYSIOLOGY 
 
 V. Nutrition — How the Body is nourished .... 76 
 
 VI. Circulation — How the Nourishment is distributed . 126 
 
 VII. Respiration — How the Blood is purified . . . 164 
 
 VIII. How the Food is used in the Body 196 
 
 IX. How the Waste Materials are thrown out of the Body . 208 
 
 X. The Skin — How it is made and what it does — how to 
 
 take care of it . 211 
 
 XI. The Special Senses — How one knows what is going on 
 
 about him ... 225 
 
 7 
 
8 CONTENTS 
 
 CIIAI'TER PAGE 
 
 XII. The Nervous System — The Brain, the Spinal Cord, and 
 
 the Nerves 237 
 
 XIII. The Muscles — How the Body moves . . . .251 
 
 XIV. TheSkeleton — The Framework of the Body . . . 263 
 
 Imdex 271 
 
PHYSIOLOGY AND HYGIENE 
 
 Physiolog-y is one of the Natural Sciences. It tells how 
 plants and animals live. It tells just what each part of 
 the living being does, and how all of the parts work 
 together. For example, it tells how the stomach digests 
 the food we eat ; how the food is absorbed and dis- 
 tributed to all parts of the body by the heart and blood 
 vessels, and how each part of the body is nourished by 
 the food thus brought. 
 
 Hygiene tells how to take care of the body. Every 
 one wishes to have a healthy body. There are many 
 things that injure the body, and many other things that 
 make the body grow large and strong and healthy. 
 Hygiene tells first, what is proper for the body, and 
 second, what will injure it, and what should therefore be 
 avoided. 
 
 Physiology treats not only of man, but of all other 
 animals, as well as of plants. Animals could not live 
 upon the earth if the plants did not prepare food for 
 them. One might think that man could live upon milk 
 and eggs and meat if there were no plants to furnish 
 vegetable food ; but a second thought makes it plain that 
 the animals which furnish us with milk, eggs, and meat 
 live upon vegetable foods, such as grass and grain. Thus 
 we are all dependent finally upon plants. 
 
 If one understands something of how plants live, that 
 is, of Plant Physiology, it is much easier to understand 
 Animal Physiology and Human Physiology. We shall 
 
 9 
 
10 PHYSIOLOGY 
 
 begin our study of physiology by the study of how a 
 plant lives and grows; then we shall study how the cells 
 and tissues, of which the human body is built, live and 
 grow, and the part which they play in bodies. This part 
 of the general science of physiology is called General 
 Physiology. 
 
GENERAL PHYSIOLOGY 
 
 CHAPTER I.— PLANT PHYSIOLOGY— HOW THE 
 PLANT LIVES AND GROWS 
 
 1. THE PLANT AND ITS NEEDS 
 
 Heke is a kernel of corn that is dry and hard, and here 
 is another which has been in water for a few days. No- 
 tice what a change has taken place in those few days. 
 The little dried-up kernel has become large, full, and soft. 
 
 Fig. 1. — a, a diy kernel of coru. li, a soaked kernel. '•, soaked keiuel from 
 which a thin slice has been cut. d, soaked kernjl cut through along the line 
 aj, (6).' e, soaked kernel cut through along the line cij, (6). The skin of 
 the kernel is peeled up and one can see the plantlet lying in its little bed 
 of food. 
 
 Inside the change is still greater. If one opens a dry 
 kernel, he will see in the midst of the white part a softer, 
 yellow part which, in the soaked kernel, has become much 
 larger and is plainly a little plant (Fig. 1). 
 
 Here is still another seed that has been in the wet earth 
 in a warm place for five or six days, and in this we see the 
 
 11 
 
12 PHYSIOLOGY 
 
 perfect little plant partly within and partly without the 
 kernel (Fig. 2, a). What suddenly started this little 
 plant to growing after lying asleep all winter? What 
 waked it up ? 
 
 It could not have been the water alone, for the kernels 
 which were put in damp soil or water and set in a cold 
 place showed no sign of life. Nor could it have been 
 
 Fig. 2. — The corn plant growing from the kernel, a shows the size of the 
 plant at one week, b shows the size at ten days, and c at two weeks. 
 
 heat alone, for those that were put in a warm window 
 without water still slept on. But when we gave them 
 both heat and moisture, they awoke and began to grow. 
 The growth, however, would soon stop if the plant had 
 no food, so nature has put the food where the plant can 
 get it most easily. 
 
PLANT PHYSIOLOGY 13 
 
 The white part and the yellow part of the kernel are all 
 the food which the plant needs until it is old enough and 
 strong enough to earn its own giving. But even with all 
 the moisture and heat and food which it needs, a plant 
 cannot be healthy without one tiling more. 
 
 You have seen a potato growing in a dark cellar, and 
 have noticed its sickly, yellow color and long, weak 
 shoots ; perhaps, too, you have seen a spot on the grass 
 wiere a board has lain for several days and which when 
 removed showed the grass with yellow blades instead of 
 green ones. 
 
 Without light there could be no green color in the 
 leaves nor strength and vigor in the plant ; without food 
 the plant could not grow, and after living for a time upon 
 its own tissue, it would die ; without moisture the plant 
 would wither and dry up ; without warmth, the light, 
 food, and moisture could not do their work. 
 
 After the plant has started to grow, it grows in two 
 directions, one part pointing up and becoming the stem, 
 and the other pointing down and becoming the root, and 
 whichever way the seed is planted, the stem will turn 
 upward even if it has to make a complete turn to get 
 started in the right direction. 
 
 If we look at the seed after the pldnt has been growing 
 for two weeks, we shall find there is little of the seed left 
 within the shell, for the plant" has eaten all the stored-up 
 food (Fig. 2, c). 
 
 2. THE PLANT AND ITS NEEDS (continued) 
 
 We have seen that a plant needs food and drink, heat 
 and light, but we have said nothing about another need 
 that is quite as great ; that is, the need of the oxygen of 
 the air. 
 
14 PHYSIOLOGY 
 
 A plant not only eats and drinks, but it breathes. All 
 plants breathe oxygen by day and by night. In plants 
 that have leaves, the leaf, is the organ of breathing ; in 
 other plants the breathing is done by means of the body 
 of the plant. 
 
 Before we can understand the use of the oxygen we 
 must know something further of the food and the Avork 
 of the plant. A plant cannot eat s*olid food. It must 
 take its food either as a liquid or as a gas. The liquid 
 food is taken from tlie earth through the roots, and the 
 gases are taken from the air through the leaves. At least 
 half of the solid part of a plant body is carbon, and the plant 
 must have a continuous supply of carbon to satisfy this need. 
 
 There are several forms of solid carbon, such as coal or 
 plumbago, but plants cannot eat solid foods, so that these 
 forms cannot be used. The plant must take carbon in the 
 form of gas, and this gas is called carbon dioxide. The 
 plant can absorb this tlirougli the leaves and use it as a 
 food. The most important food of a plant is carbon diox- 
 ide, which is absorbed from the air by the leaves. 
 
 Carbon dioxide is composed of carbon and oxygen. 
 Carbon when alone is a solid like coal, or coke, or plum- 
 bago. Oxygen Avhen alone is a gas. The air is composed 
 of a mixture of gases, of which oxygen comprises about one 
 fifth of the whole amount. When oxygen and carbon are 
 joined together they make a gas which is called carbon 
 dioxide gas. Carbon dioxide forms a very small part of 
 the air. The leaves absorb the carbon dioxide, and if the 
 plant is in the sunlight, the green coloring matter in the 
 leaf separates the carbon from the oxygen. The carbon 
 remains in the plant as a part of the plant, while the 
 oxygen escapes from the leaves as a gas. All of this 
 wonderful process is a part of the plant's eating. 
 
PLANT PHYSIOLOGY 15 
 
 To understand the way in which a plant breathes, we 
 must study the subject of oxidation. Have you noticed 
 that a fire which has been given plenty of coal will stop 
 burning if we close the draught? If the draught is not 
 perfectly closed, the fire will burn slowly; but if quite 
 closed, the fire will go out. It is plaih that the fire needed 
 something which it did not get. It had no oxygen. The 
 coal cannot burn without the help of oxygen. This 
 burning we call Oxidation. 
 
 You have seen copper become tarnished and iron be- 
 come rusted when exposed to the air. In both cases they 
 have become oxidized. When the coal became oxidized, 
 it was a quick process which we call rapid oxidation, but 
 when the iron became oxidized it was by slow oxidation. 
 
 Oxidation always produces heat. Jlapid oxidation takes 
 place in a short time with a great hS.at, while slow oxida- 
 tion gives little heat during a long time. 
 
 Heat may be used for warming houses, for cooking, or 
 for producing power to move machinery. 
 
 In the plant oxidation is used priijcipally for power to 
 do the work of the plant. The plant work is to push 
 itself upward and to carry food from the ground to the 
 highest point, and later to form the seed. It is tlie union 
 of carbon and oxygen that gives the plant power to grow 
 and to feed itself, and to make a new plant. 
 
 As the leaf is the organ for inhaling*, it is also the organ 
 for exhaling. This is done by means of the cells in the 
 surface of the leaves. Let us remember, then, that every 
 plant has work to do ; that to get the power to do this 
 work it must oxidize its own substance with the oxygen 
 of the air. Remember that oxidation of the substance of 
 a living plant or animal is hreathing. All living things 
 breathe in oxygen, which combines with the carbon and 
 
16 PHYSIOLOGY 
 
 other substances to form carbon dioxide and other com- 
 binations, such as water. After the carbon dioxide is 
 formed it is always thrown out of the animal body, but 
 the plant leaves can use it for food when the sun shines. 
 
 3. THE PARTS OF A PLANT 
 
 We found the first need of a plapt to be warmth and 
 moisture, and found, too, that for days the plant could 
 live upon nothing more than the food in the seed, with 
 the water which it took in through the roots and the 
 oxygen absorbed by the leaves from the air, 
 
 We can easily understand from this that a large part 
 of a young plant and some part of all plants is fluid. 
 
 The fluid is in every part of the plant, and when it 
 is mixed with the food it becomes the sap. If you have 
 tasted maple sap, you will remember that it was not like 
 water, but was thicker and tasted sweet. That is because 
 it has taken up the food of the plant, which it must carry 
 to every part. 
 
 Besides the liquid part the plant has another part, and 
 this part we call the tissue, just as we call the substance 
 of your dress or coat, the material, the fabric, or the 
 tissue. As the tissues have different uses, we call them 
 by different names. Those that are active and do the 
 work of the plant, we call active tissues; those that sup- 
 port the active tissues we call supporting tissues, and those 
 that cover and protect we call protecting tissues. Let us 
 see if by thinking a little we can find which tissues belong 
 to each division. 
 
 We know that the work of this plant is done by the 
 leaves, the root, and the stem. 
 
 In all of these organs we find thp living substance of 
 
PLANT PHYSIOLOGY 17 
 
 the plant, which is called protoplasm. In the leaves it is 
 green protoplasm, and in the stem and roots it is white 
 protoplasm. All of the active tissues of the plant con- 
 tain protoplasm, and are in the leavers, in the stem, and in 
 the root. Most of the leaf is active tissue, but only a 
 small portion of the stem and root is active tissue. The 
 delicate root hairs contain protoplasm and represent active 
 tissue. 
 
 If you hold a leaf up and look through it toward 
 the light, you will see the branching veins of the leaf. 
 These veins serve a double purpose in the leaf ; (1) they 
 support the active tissue of the leaf ; (2) they serve as a 
 circulatory system along which the sap of the plant flows. 
 The stem is made up almost wholly of supporting tissue, 
 the only active tissue being the inner bark in the case of 
 trees and shrubs. What is true of a stem of a tree is 
 also true of a root. 
 
 Protecting tissue is found upon every plant. The 
 delicate, transparent skin which covers the little corn 
 plant is its protecting tissue. The thick bark which 
 covers the trunk and branches of trees and shrubs is their 
 protecting tissue. Seeds have protecting tissue. The 
 transparent skin so easily peeled off -from a soaked kernel 
 of corn is its protecting tissue. A nut has a hard, woody 
 shell outside and a delicate brown skin inside, to protect 
 it as it lies upon the ground all winter, waiting for the 
 warm spring sunshine to wake it up. 
 
 4. THE PLANT ORGANS 
 
 The tissues are but the materials of which the working 
 part of the plants is made, and these working parts we 
 call Organs. 
 
 hall's phys. — 2 
 
18 PHYSIOLOGY 
 
 We have already spoken of the leaf as the orgau of 
 breathing. On its surface both above and below are cells 
 through wiiich the oxygen passes. The leaf is formed of 
 the three kinds of tissue. Inside is the living part or 
 protoplasm, kept in place by the supporting tissues, the 
 veins, and the whole leaf covered by the protecting tissue 
 or skin. 
 
 The work of feeding is shared by two organs, the leaf 
 which gets the gaseous food from the air, and the root, 
 which gets the liquid food from the gi-ound. This organ 
 is composed of all three tissues. In large plants the main 
 part of the root is supporting tissue, whose work is to 
 hold it upright and firmly fixed in the ground ; but each 
 large branch of the root has a thin coat of active tissue 
 under its bark. In small plants like the little com plant, 
 the main part of the root is active tissue, composed of 
 fine rootlets and root hairs, all filled with protoplasm and 
 sap, and held in form and made strong by the cellulose, 
 and covered and protected by the skin. 
 
 The stem with its branches is the organ of form, and 
 gives to the plant its shape. Without this part the plant 
 could not grow tall, nor send out arms, nor have any of 
 the beautiful forms which plants now take. It would lie 
 flat and formless. 
 
 The little corn plant which we have been studying has 
 no other organs than the root, stem, and leaf, but in a 
 mature plant there is still another organ, the flower, to 
 which is given the highest work of the plant. The 
 flower often adds beauty, color, and fragrance, but these 
 things are not its real work. Its work is the making of 
 a new plant of the same kind as the parent plant, and this 
 is the crowning work of the whole plant. During the 
 entire summer the leaves breathe in oxygen, the roots 
 
PLANT PHYSIOLOGY 19 
 
 take in food, the veins carry it all over the plant body, all 
 to give the plant strength to form the seed, which holds 
 the sleeping plant for the following year. This work of 
 making the seed and storing up within it the food for the 
 young plant is so hard that it requ.ires the help of the 
 whole plant. But, as upon the seed depends the future 
 good of the plant family, so each plant gives its work for 
 the family good. 
 
 It is so important that the plant prepare this seed and 
 ripen it that if it cannot get the proper food and drink 
 for growth and seed making, instead of using what it 
 does get for its own growth, it sacritices its growth and 
 hastens to form the flower, which in turn will produce the 
 seed and insure the next year's plant. 
 
 5. THE SEED AND WHAT IT CONTAINS 
 
 Wjb have talked about the young plant and its needs ; 
 the growing plant and its needs ; the material from which 
 the plant is made ; and the organs of the plant and their 
 work. The most important organ we found to be the 
 flower, and its most important work the making of the 
 seed. Now we will talk about the seed and its material. 
 Let us look first at the outside. Here is a seed that has 
 been in water for three or four days (Fig. 1, page 11). If 
 you use a penknife or a pin, you can loosen the outside 
 part or skin. Look at it and see how tough it is. When 
 it was on the kernel, it looked yellow, but when it is taken 
 off, it looks colorless, and we now know that the color 
 showed through and that the skin itself is transparent. 
 Did you notice where the skin stopped? If you look 
 carefully enough, you will see that the point of the seed is 
 not covered. This is where the kernel is fastened to the 
 
20 PHYSIOLOGY 
 
 cob. The skin is entire over the seed except over this 
 point. 
 
 Now we have taken off the skin and can see the body of 
 the kernel. Look at the soaked kernel in which the parts 
 have become swollen and are more easily seen. Now the 
 little plant or germ can be loosened from the other part 
 which is the plant food. In this seed that has been in the 
 warm earth for five or six days the parts of the germ can 
 be seen : the point which grows upward called ^q plum- 
 ule, and the point which grows down called the radicle. 
 Notice that what was a groove in the dry seed has filled 
 out in this soaked seed, and in the seed that has been 
 growing for a week we can see the root growing down- 
 ward from the pointed end of the seed, and the plumule 
 growing upward from the middle of the side of the kernel 
 in which the germ lay. Notice that on one side of the 
 kernel there is a little bed of soft yellowish substance, in 
 the midst of which the germ lies. This soft yellowish 
 substance forms the first food of the little plant when 
 it wakes up or sprouts in the spring. 
 
 It will be interesting to find of what the seed and the 
 germ are composed. 
 
 The germ itself is composed largely of protoplasm 
 within thin cellulose walls and covered with a thin skin. 
 Around this tender germ is a layer that is nearly all pro- 
 toplasm or proteid, and around that layer is the main part 
 of the seed, which is starch. On each side of the ker- 
 nel is a yellow part which contains the oil mixed with 
 starch, and besides these materials are some minerals, 
 such as salt and lime. 
 
PLANT PHYSIOLOGY 21 
 
 EXPERIMENTS 
 
 Get five cents' worth of iodine from the drug store. 
 Dilute a part of this with water to a light brown color. 
 Make a thin paste of laundry starch boiled with water. 
 
 1. Put some of this paste in a drinking glass. Pour 
 into the starch a little of the dilute iodine, and notice that 
 the starch instantly turns to a beautiful blue color. This 
 is called the iodine test for starch. 
 
 2. Put a little piece of lean meat in some of the strong 
 iodine and notice that the meat turns brown. This is the 
 iodine test for proteid (see page 85). 
 
 3. Cut some thin slices across a soaked grain of corn ; 
 put, them into any little shallow dish like a watch crystal 
 or a butter dish, and notice that the white part of the 
 kernel turns blue, showing the presence of starch ; and 
 that the 3''ellow part around the germ turns brown, show- 
 ing the presence of proteid there. The germ itself turns 
 brown because its protoplasm is one kind of proteid. 
 
 4. Remember tiiat the kernel, contains the first food 
 of. the plant ; that this food is composed of starch, of 
 proteid, and of oil ; that iodine turns starch blue and 
 proteid brown. 
 
 6. PLANT DIGESTION 
 
 We know that as plants eat they must have food, and 
 that it must be in a form in which the plants can use it. 
 As they can take no solid food, they must take all of their 
 nourishment in the form either of gas or of liquid, and as 
 many foods are not soluble in water, there must be some 
 other process which changes them to a liquid form. This 
 change is called digestion. 
 
22 PHYSIOLOGY 
 
 Plant digestion is of two kinds, the digestion of the 
 seed food, wliicli takes place witliin the seed when the 
 germ first wakes up and is feeding u]jon tlie food stored 
 for it by the parent plant ; and the digestion of the soil 
 food, which the roots take up from the ground. 
 
 It often happens that both kinds of digestion are going 
 on at the same time ; for example, when the wakened 
 germ is living mainly upon the seed fo'od, but has sent out 
 one or two roots which bring in new material from the 
 ground. As the roots can take only liquid food and the 
 leaves only gaseovis food, all changes in the food — or 
 digestion — must take place outside of the plant body. 
 Therefore the plant has and needs no digestive organs, 
 but it does have digestive fluids, which it sends out to 
 dissolve mineral matter or to change it into a liquid that 
 can be taken up. 
 
 We found a large part of the kernel of corn to be 
 starch ; but if you were to examine the plant itself, you 
 would find no starch at all, and yet the germ plant lives 
 upon that stored-up starch. It is evident then that 
 some change must have taken place in the food. 
 
 The foods that are found in seeds are either sugar, 
 starch, oil, proteid, or cellulose, and all of these excepting 
 the sugar must be digested before they can be used by the 
 growing germ, and must be digested by some ferment. 
 
 Do you know what is meant by a fbrment? If you put 
 corn or beans to soak in water for several days, you will 
 find that the water becomes cloudy and has tiny bubbles 
 on top ; that shows the work of a ferment. Tlie same 
 ferment will not digest all the kinds of food which seeds 
 contain, but it requires one kind of ferment for oil, one 
 kind for proteid, and another for stardh and cellulose. 
 
 Knowing that the food cannot be digested without a 
 
PLANT PHYSIOLOGY 23 
 
 ferment, we naturally'want to know where this ferment 
 comes from and what it does. 
 
 Let us go back to our first lessons, and we shall find that 
 the plant germ sleeps in the seed until it is wakened by 
 the action of the heat and moisture working together. If 
 the germ has only water or only heat, it sleeps on, but 
 when it has both in the right amount, it wakens. 
 
 Bears and some other animals sleep during the winter 
 in some warmly covered, dark place, neither eating nor 
 drinking, and breathing but slightly. In the spring they 
 waken and are so hungry that when we wish to express 
 great hunger we say " as hungry as a bear. " 
 
 The germ within the seed also sleeps during the winter 
 and wakens in the spring " as hungry as a bear." The 
 mother plant had prepared for this hunger, and right at 
 hand the wakening germ finds food. When the proto- 
 plasm is wakened, it forms a ferment out of its own sub- 
 stance, and this ferment digests the different foods. One 
 kind of ferment digests the starch and cellulose, anotlier 
 kind digests the oils, and still anothe'r the proteid matter. 
 After the food has been acted upon by the ferment it is 
 ready for the plant to use in building up new parts. 
 
 All the seed foods are digested in tliis way; but when 
 the plant becomes old enough and strong enough to put 
 out roots and to produce root hairs, then the plant uses 
 another kind of digestion. The young plant carries on 
 first the ferment digestion and then both kinds of digestion 
 at once until the seed food is all used up. 
 
 From the soil the plant takes up mineral food, of which 
 it could get very little from the seed. 
 
 A plant must have mineral matter to make it strong 
 enough to stand Tipright. 
 
 The minerals of the soil are solid, and are not soluble 
 
24 
 
 PHYSIOLOGY 
 
 in water. If they were, the rains would wash them away, 
 as they have washed the soluble salt, into the sea. 
 
 Before minerals can be used as plant food they must be 
 dissolved, and water will not do it. A way has been pro- 
 vided by means of the root hairs. These root hairs make 
 an acid which dissolves the grains of mineral matter which 
 are held close to the root by the close-growing root hairs. 
 As soon as the mineral is dissolved it is taken up by the 
 root hairs, forms a part of the sap, g,nd thence is carried 
 all over the plant, where it is built up into the growing 
 tissues, giving it that firmness which only mineral food 
 can give. Some of the minerals used are quite common 
 to us, as the lime and salt, but others quite as useful to 
 the plant are not so well known to us. Some plants 
 require more of one mineral, and others more of another 
 kind, and this is one reason why different plants require 
 different soils, and why it is better not to grow one kind 
 of grain on a field year after year, but to change each 
 year, thus having " a rotation of crops." 
 
 REVIEW OP PLANT PHYSIOLOGY 
 The Plant Needs : 
 Water 
 Heat 
 Light 
 
 1 Gaseous, Carbon dioxide 
 Oxygen 
 The Plant Substance : 
 
 Active : Protoplasm 
 
 I Of leaves 
 Of stem 
 Of roots 
 ( Of root hairs 
 
 Supporting 
 
 Veins 
 
 Cellulose 
 Protecting : Skin 
 Fluid: Sap 
 
PLANT PHYSIOLOGY 
 
 25 
 
 The Seed 
 
 Digested by fenneiits secreted by plant germ. 
 
 The Plant Organs : 
 
 Leaf — organ for breathing and eating gas. 
 
 Stem — organ for form. 
 
 Root — organ for eating. 
 
 Flower — organ for producing a new plant. 
 
 Skin 
 
 I Plumule 
 Radicle 
 Sugar 
 Starch 
 Food \ Oil 
 
 Proteid 
 . Cellulose 
 
 The Plant Digestion: 
 
 Of Seed Food: 
 
 Sugar 
 
 Starch 
 
 Cellulose 
 
 Proteid 
 
 Oil 
 
 Of Soil Foods: Mineral matter digested by and absorbed by the 
 root hairs. 
 
 The Plant Economy : 
 
 In Food stored fur future use : 
 
 Root 
 
 ( Underground 
 
 ( Aerial 
 Seed 
 
 In Sleep during the Winter: 
 Germ plant sleeps in seed. 
 Adult plant sleeps. 
 
 In eating Carbon dioxide. 
 
 In breathing oxygen, to get the energy which the plant needs to do 
 
 its work. 
 In changing mineral matter to vegetable tissue which is built up 
 
 into the plant. 
 
 Stem 
 
26 PHYSIOLOGY 
 
 THE RELATION OF PLANTS TO ANIMALS 
 
 Plants can digest minerals and change them to a form 
 which the animal may use. 
 
 Plants can eat carbon dioxide and water, and from 
 these two substances can make sugar, starch, and oil, all 
 of which are used by animals for food. 
 
 Carbon dioxide is harmful to animals. As the plants 
 consume it they make the atmosphere more healthful for 
 the animals. Thus animals owe a great debt to the plants. 
 
 Plants could not do these wonderful things if it were 
 not for the sunshine. Thus we see that all nature is 
 bound together into one great harmonious whole. 
 
CHAPTER II. —THE CELLS, TISSUES AND 
 ORGANS OF THE BODY 
 
 1. THE GENERAL STRUCTURE OF THE BODY 
 
 In our study of the plant we found that its body is com- 
 posed of organs; namely, the root, stem, leaves, and flowers. 
 We found that each one of these parts of the plant body 
 did a special part of the work which the plant has to do. 
 
 In a similar way the body of every animal is composed of 
 organs, and each organ has a particular work to do. The 
 stomach is an organ whose work is to digest food ; the heart 
 is an organ whose work is to pump the blood through the 
 arteries and veins to the various part^ of the body. The 
 skin is an organ whose principal work is to protect the 
 sensitive organs which it covers. 
 
 The skin is a coat which the body always wears. In 
 our cool and changeable climate the skin does not furnish 
 enough protection, so that animals are furnished by Mother 
 Nature with thick, warm coats of fur. But man is endowed 
 with higher faculties than are the lower animals and-, left 
 upon his own resources, he makes for himself a thick. Warm 
 garment. He uses various materials, weaves them into 
 fabrics, and then combines the fabrics into a garment. 
 This garment, which we will suppose is a coat, is an organ, 
 perfectly adapted to do a special kind of service for the 
 man. 
 
 Let us study this artificial organ, this coat, to see how 
 it is constructed. It has a thicker outside and a thinner 
 
 27 
 
28 PHYSIOLOGY 
 
 lining. It may also have a middle layer to make it warmer ; 
 that is, better adapted for its work. These layers of which 
 the coat is composed are of fabrics ; that is, they are tissues. 
 Any piece of cloth is a fabric or tissue. But how are 
 these fabrics constructed? If you examine a piece of 
 cloth, you will find that it is made of threads woven 
 together. If you examine a thread, you will find that 
 it is composed of fibers. So that this artificial organ, 
 a man's coat, is composed of fabrics or tissues ; the tissues 
 are composed of fibers or bundles of fibers. 
 
 In a similar way organs of the body are composed of 
 various layers of tissues, and these in turn are composed of 
 fibers, and bundles of fibers woven together. Some tissues 
 are composed not of a woven layer of fibers, but of tiny 
 globular, cylindrical, or rectangular bodies set side by side 
 like the bricks or blocks in a pavement. These little 
 bodies are called cells. 
 
 So we may remember that the body is composed of 
 organs, the organs are composed of tissues, and the tissues 
 are composed of fibers or cells. 
 
 2. THE CELL— WHAT IT IS AND WHAT IT DOES 
 
 If one looks very closely at a slice of watermelon, he 
 will be able to see that it is composed of tiny spherical 
 globules lying side by side. They are almost too small 
 to see without the help of a magnifying glass, and yet 
 there are few plants which have larger cells, and most 
 plants have smaller ones, too small, in fact, to be seen 
 without a magnifying glass or a large microscope. 
 
 The compound microscope was invented by a Hollander 
 about three hundred years ago, but little practical use was 
 made of it until a century later, when it began to be used 
 
CELLS, TISSUES, AND ORGANS 
 
 29 
 
 for the study of plant and animal tissues. It was very 
 soon discovered that plant tissues are composed of little 
 chambers which are spherical, cylindrical, cubical, pris- 
 matic, spindle-shaped, or irregular in form. The early 
 workers with the microscope chose the name cell for these 
 little chambers. When it was discovered that the cells 
 
 Fig. 3. — Diagram of a cell. [After Wilson.] Notice in this diagram of a 
 typical cell the cell protoplasm, composed of cell plasm and cell lymph, and 
 containing cell foods (C./.) and cell sap {Cf.). The large spherical nucleus 
 has a true nucleolus (t.n.) , a false nucleolus (J-n.) , a nuclear network {N.n.) , 
 and nuclear lymph {N'.l.) . c is the centrosome. 
 
 were usually filled with a liquid, it was not known how 
 important this liquid is. 
 
 It was found out later that the liquid inside the little 
 chambers is alive and is of far more consequence than the 
 house in which it lives. The living substance is called 
 protoplasm. Each little globule of protoplasm builds a 
 wall around itself. At first this wall was called a cell. 
 
30 
 
 PHYSIOLOGY 
 
 N ■ , 
 
 Now we use the word cell for the ffiobule of living proto- 
 plasm together with its wall. 
 
 Protoplasm is not a clear liquid like water, but is com- 
 posed of a network whose meshes are filled with a clear 
 watery fluid which is called cell lymfh. The network is 
 composed of threads or strands of a grayish, sticky sub- 
 stance called cell plasm. The cell jjlasm is filled with 
 
 minute grains. If the 
 reader makes a care- 
 ful study of Figure 3, 
 he will find all of 
 the parts mentioned 
 above ; and in addi- 
 tion to these he will 
 find the spherical 
 nucleus in the middle 
 of the cell. The 
 Hucleus has a wall, 
 a network whose 
 meshes are filled with 
 lymph, and holds two 
 small spherical bod- 
 ies, the true and the 
 false nucleoli. 
 
 If the reader now 
 studies Figure 4, he 
 will see practically 
 the same parts in a different combination. This cell is 
 a plant cell, and the cell sap is much more abundant in 
 proportion to the protoplasm than is the case in the animal 
 cell. All plant cells have walls. Sometimes the walls 
 of a plant cell are very thick. 
 
 Animal cells differ from plant cells in two very impor- 
 
 Fio. 4. — A typical plant cell. [Bastin.] 
 
 Pr. shows the protoplasm, with its graoules, 
 but the network is not shown. The cell sap 
 (c.«.) occupies a very large part of the cell. 
 The cell food (c/.) makes a prominent addi- 
 tion to the flgures. N, the nucleus, contains 
 the true nucleus {t.n.). This cell had seven 
 boundary cells. 
 
CELLS, TISSUES, AND ORGANS 
 
 31 
 
 tant ways : (1) they have a very thin membranous wall 
 or perhaps no wall at all ; (2) they have one or two small 
 collections of cell sap, or more frequently no sap at all. 
 Study Figures 5 and 6 and compare them carefully with 
 
 .1 
 
 E. 
 
 F. 
 
 Fro. 5. —Typical cells of animals and plants. 
 
 A cell such as found in the lining of the windpipe. The little hairs on the 
 top keep moving qnickly in one direction and slowly in the other, and 
 thus carry dust and mucus up to the throat from the lungs. 
 
 B, A cell from the windpipe, or nose, or intestine,. This kind of cell is called 
 
 !i goblet cell. It is full of clear mucus. From time to time the cell 
 empties out its mucus. 
 
 C. A cell from the stomach. This kind of a cell helps the stomach to digest 
 the food. Its part of the work is to help make the gastric juice. 
 
 One of the blood cells. 
 
 A plant cell. Notice: the numerous vacuoles filled with cell sap (C'.s.) ; the 
 cell protoplasm (C'.p.) iilled with innumerable tiny granules ; the little 
 masses of cell food(C./.): the large nucleus with its nucleoli and network.' 
 The cell has a heavy wall, and one can see where seven other cells join it. 
 
 A typical animal cell [Wilson]. 6'.;)., cell plasm; T/.i., cell lymph; C.f., 
 cell food; Cs., cell sap; if., nucleus; vi., nucleolus. 
 
 Figures 3 and 4. Remember that the important part of a 
 cell is the living protoplasm^ and that the protoplasm is 
 composed of a network of cell plasm, whose meshes are 
 filled with cell lymph; that the cell contains the nucleus, 
 which has a networli ajid nuclear lymph and contains one, 
 
32 
 
 PHYSIOLOGY 
 
 two, or three nucleoli; that there may be little masses of 
 cell food ; and small globules of cell sap ; and, finally, that 
 the plant cell nearly always has a 
 thick cell wall while the animal 
 
 ^ ,„ cell usually Ims a very delicate 
 
 tjt/ membranous wall. 
 
 8. THE CELL, AND WHAT IT 
 DOES {continued). 
 
 From the preceding lesson we 
 have learned something about the 
 parts of a cell. It seems wonder- 
 ful that all these parts can be 
 found within an object too small 
 to be seen without a microscope. 
 "When we learn of the work which 
 the cell is doing and the part which 
 it plays in the world, it will all 
 seem like a fairy story, but all 
 Fig. 6.— A typical animal cell, of the facts to be given here have 
 
 Notioe that in this cell all the -i i i . , 
 
 parts except the cell sap may been observed many times by men 
 be found. [Verworn.] ^\^q devote their lives to the study 
 
 of these problem,s. 
 Every one has noticed the green powder which collects 
 upon the tree trunks, fence posts, and stones or bricks 
 which are in damp places out of doors. If one were to 
 put a few grains of this green dust in a drop of water 
 upon a glass and look at it with a strong microscope, he 
 would find each grain to be spherical in shape, to have a 
 transparent cell wall, and to be filled with a grayish mass 
 in which may be seen many tiny green granules. These 
 little spherical bodies are cells. Each one is a complete 
 
CELLS, TISSUES, AND ORGANS 
 
 33 
 
 plant (Fig. 7). Its green granules are the same as those 
 which make the corn, wheat, grass, and trees green in 
 
 Fig. 7. — Protococcus, a dustlike, one-celled green plant, seen as a powder 
 upon the trunks of trees, upon fences, stones, etc. In 6, c, and d is shown 
 the way in which the mother cell divides up into4wo, three, or more daughter 
 cells. After division the cells may remain together in a colony, as in 6 or c, 
 or they may separate, as shown in d. 
 
 color. If one examines under a niicroscope a drop of 
 water from a pool or pond that has been standing stag- 
 nant for several weeks 
 during the summer, he 
 is sure to find little 
 green bodies similar 
 to the ones we have 
 just studied. These 
 are cells also. Some 
 of them have little 
 moving hairs whose 
 whiplike motions pro- 
 pel the cells through 
 the water (Fig. 8). 
 Each of 'these one- 
 celled plants leads an 
 independent life. Each 
 receives the light and 
 warmth of the sun in 
 its green granules. 
 Each eats carbon dioxide gas and water; each makes 
 sugar, and starch, and protoplasm. Each begins as a 
 hall's phts. — 3 
 
 Fig. 8. — One-celled water plants. One of them 
 (a) has a little whiplike tail whose rapid 
 movements propel the plant through the 
 water something like the swimming of a 
 tadpole. But they are so small that hun- 
 dreds of them would have plenty of room 
 in a drop of water. 6 and c are Desmids, 
 chiefly noticeable for their beauty. 
 
34 
 
 PHYSIOLOGY 
 
 very small cell and grows larger and larger until it 
 becomes a grown up or adult cell. Each one raises 
 a family of daughter cells, as they are called. Finally 
 each one gets old and dies. 
 
 If one examines under a microscope a drop of water 
 which he has taken, with a glass tube, from the slimy 
 bottom of a stagnant pool, he is likely to see little glob- 
 ular or irregular grayish bodies, which keep changing 
 
 Fig. 9. — AnAnKeba. a shows the animal in a resting stage or asleep, ftshows 
 It as it starts out for something to eat. e and d show it coming in contact 
 with a diatome and swallowing it through a mouth made for the occasion. 
 
 shape and creeping across the glass on which the water 
 lies. These curious objects are living creatures which 
 belong to the animal kingdom. 
 
 These little animals are called Amaehce. When an 
 amceba sleeps or rests, or when it is afraid, it draws 
 up into a ball (Fig. 9, a). When an amoeba ge'ts hungry, 
 it projects feet right out of its side anywhere. With 
 these false feet, as they are called, it creeps over the 
 surface on which it rests until it comes to some object 
 which it can eat, when it opens a m*outh anywhere and 
 takes the object in. The figure (Fig. 9, d") shows the 
 amoeba in the act of swallowing a little one-celled plant. 
 The amoeba grows larger as it grows older. After a 
 
CELLS, TISSUES, AND ORGANS 
 
 35 
 
 while it becomes an adult mother amoeba ; then it di- 
 vides into two daughter ainocbEe. This process of raising 
 a family is shown in Figure 10. 
 
 Mention has already been made of the movements made 
 by the plant (Fig. 8) and by the hungry amceba. If one 
 breaks off a slimy spray of a fine water plant and looks at 
 
 Fig. 10. — An adult amoeba dividing into two daughter amoebse. Notice that 
 eacli daughter has a share of the parent nucleus, as well as a share of the 
 parent protoplasm. [Hall.] 
 
 it under a microscope, he is likely to find some interesting 
 little animals like those shown in Figure 11. The most 
 noticeable feature of these one-celled animals is that when 
 everything is quiet they extend the stem to its full length 
 and open their bells as wide as possible. Each of these 
 animals has a row of hairlike arms or tentacles called 
 cilia around the bell. When anything disturbs, startles, 
 or irritates them, they instantly fold the bells in, draw the 
 
36 
 
 PHYSIOLOGY 
 
 cilia together, and contract the stem until they occnpy 
 the smallest possible space. This all shows that they 
 
 are sensitive, and that 
 they can respond to a 
 stimulus. 
 
 Remember that all 
 cells begin as small 
 young cells and grow 
 up to adult life by eat- 
 ing; that all cells have 
 to work for their living; 
 that all cells breathe in 
 oxygen and breathe out 
 carbon dioxide gas ; that 
 all cells are sensitive to 
 thipgs or conditions out- 
 
 FiG. 11. — A Stentor {a, b) and a Vorticella • t j^ ,i -i j 
 
 (c,d). a and c show these little one-celled Siae 01 tnemseives ; ana 
 
 animals relaxed, with the hell open, and that many Cells have the 
 
 the little hairs around the mouth ol the . 
 
 bell waving the particles oi food into the pOWCr 01 motion. 
 
 open mouth of the bell. 6 and c show Remember that many 
 
 both animals contracted after something i ■ i 
 
 has startled them. [Verworn.] plants and animais Con- 
 
 sist of only one cell. 
 
 4. TISSUES — HOW THEY ARE MADE AND WHAT 
 THEY DO 
 
 If you will turn back to Figure 7 and Figure 10, you 
 will see that full-grown plant cells and full-grown animal 
 cells divide into two or more young cells which begin life 
 as small, restless, hungry cells which forage for food, eat 
 ravenously, and grow rapidly into adult cells. In the 
 amoeba the daughter cells separate, and each one goes off 
 by itself where it must fight its own battles single handed. 
 
CELLS, TISSUES, AND ORGANS 
 
 37 
 
 There are man}^ little water animals larger and stronger 
 than the amreba, which hunt for it, and when they find it 
 devour it as a tender 
 and nourishing mor- 
 sel. The little green 
 plant, Protocoecus, 
 shows us something 
 new. Notice that in 
 b and c (Fig. 7) the 
 daughter cells do not 
 separate, as do those 
 in d, but remain to- 
 gether in a little 
 family or colony. 
 Figure 12 shows a 
 plant of a higher 
 order than the pro- 
 tococcus. It is placed 
 in a higher rank be- 
 cause it is better fitted for the varying conditions of life. 
 How is it better fitted ? Just as a colony of men is better 
 fitted than one person to meet the dangers of a pioneer 
 life, so is a colony of cells better fitted to meet the dangers 
 which exist in the pond or on the tree trunk. In union 
 ia strength. The enemy strong enough to overcome an 
 individual easily does not dare to attack a colony, and 
 thus the dangers are lessened. There is another great 
 advantage in colonial life. Notice that both the colonial 
 animal and the colonial plant have two kinds of cells. 
 The outer cells of the little plant in Figure 12 are pro- 
 vided with delicate whiplike arms. With these arms the 
 outer cells move the whole colony through the water or 
 along the bottom of the pond or aquarium. The outer 
 
 Fig. 12. — A little water plant composed of a 
 colony of cells held together hy a mass of 
 gelatinous substance. [Verworn.] 
 
38 PHYSIOLOGY 
 
 cells of the little sponge are similarly provided with whip- 
 like arms, which have little cups into which they may 
 withdraw for protection (Fig. 13). 
 
 In a similar way the individuals in a colony of men do 
 not all perform the same kind of work, but some will be 
 builders, others will grow grain and vegetables, and so 
 on, each being especially fitted for his own work. 
 
 Fig. 13. — A little animal, a kind of sponge, composed of a colony of cells held 
 together by a mass of gelatinous substance. [Verworn.] 
 
 Nature has used this principle of the colony and has 
 produced all the higher plants and animals in harmony 
 with the principles which govern a colony or community. 
 The largest animal or plant is only a great colony of cells, 
 each cell. having its special work to perform. In a large 
 colony or community of people, there will be a great 
 mBny who devote their whole energy to producing the 
 things which serve for nourishment or nutrition ; others 
 will devote themselves to transportation, carrying nour- 
 ishment and building material from one place to another ; 
 others will be builders ; others will be the protectors and 
 
CELLS, TISSUES, AND ORGANS 
 
 39 
 
 serve in the army or on the police force. In a similar 
 way the cells of the digestive system of an animal are 
 engaged in preparing food ; the cells of the circulatory 
 system are engaged in transporting this food to all parts 
 of the body where it is needed ; the cells of the cuticle, 
 hair, nails, are engaged in protecting the body. 
 
 Any group of similar cells engaged in a similar work 
 makes a tissue. Tissues may be composed of cells alone 
 
 ■it^^^*.^.^ 
 
 v;tn 
 
 :o. 
 
 
 Fig. 14. — A thin slice of cartilage or gristle. Slice a shows the clear, brittle 
 cartilage which is found at the ends of bones. Slice b shows the yellowish, 
 tough cartilage which forms the cushions between the vertebrae. [From 
 Miller's Hiatology.] 
 
 or of cells together with substances which the cells have 
 formed and which they use in their work. A transporta- 
 tion system consists not only of the men directing it, but 
 of their railroads, trains, and so forth. So a tissue may 
 consist of more than the simple cell bodies. Figures 12 
 and 13 show between the cells a gelatinous substance 
 made by the cells for the purpose of holding the cells 
 together in a colony. This gelatinous substance together 
 with the cells makes a tissue. The little plant and animal 
 shown above (Figs. 12 and 13) are really tissues, but 
 more complex plants and animals may be composed of 
 many tissues. 
 
40 PHYSIOLOGY 
 
 Figure 14 shows a thin slice of cartilage or gristle as it 
 would look under a high-power microscope. Cartilage is 
 a tissue of the human body used principally in the joints. 
 
 Figure 15 shows connective tissue fibers woven into a 
 network. In both the cartilage and the connective tissue 
 the cells are of much less importance than the substance, 
 
 Fig. 15. — Connective or supporting tissue taken irom beneath the skin. 
 Notice that there is a loose network of wavy bundles ol fibers, also a net- 
 work of threadlike fibers. All of these fibers were formed by the cells which 
 you see lying in the meshes. [Schaefer.] 
 
 matrix, or fibers, which they have formed. In fact, the 
 work of the connective tissue cells is done when they 
 have made the connective tissue fibers. The fibers do 
 the work of the connective tissue. 
 
 5. ORGANS — HOW FORMED AND HOW GROUPED 
 
 In a previous lesson the coat was likened to an organ, 
 and its various fabrics (outside, lining, and padding) to 
 the various tissues which compose an organ. The stom- 
 ach is an organ. It is composed : (1) of a smooth, shiny 
 outer layer ; (2) of a muscular layer ; (3) of a layer of 
 loose connective tissue, like that shown in Figure 15 ; 
 and (4) of a layer of cells set close together like the 
 
CELLS, TISSUES, Am) ORGANS 
 
 41 
 
 Y 
 
 >G 
 
 JD 
 
 F, external, oblique, and longitudinal mus- 
 cular layers. 
 
 blocks or bricks in a pavement. The work of the stomach 
 is to help digest the food. To do this work of the stom- 
 ach, the inner layer of 
 cells is needed to make 
 the digestive fluid. 
 The connective tissue 
 is a supporting tissue. 
 The muscle tissue 
 causes the churning 
 movements which the 
 stomach makes when 
 it is digesting food; 
 
 and the outside, Fig. 16. —Diagram of a slice of the wall of the 
 
 smooth shinv laver stomach, a, mucous membrane; B, Sub- 
 
 ' . '' . •' mucosa; C, muscular coat ; i), fibrous coat; 
 
 is supporting tissue JE, internal circular layer of muscular fiber ; 
 
 which gives form to 
 the stomach and cov- 
 ers the muscles to protect them. So we see that the 
 stomach is an organ with a general work to do, and that 
 it is composed of tissues, each of which has a special part 
 of the work. Now each one of the tissues is composed of 
 cells which are practically all alike. For example, all of 
 the cells of the muscular coat are alike and all work to- 
 gether doing the same kind of work. All of the cells 
 which make up the inner lining of the stomach are alike 
 and work together to make the fluid which digests the 
 food in the stomach. Figure 16 shows how a piece of 
 the wall of the stomach would look under a microscope. 
 
 The intestine is an organ. Its general work is to assist 
 in the digestion of food. It is composed of four layers of 
 tissue quite like the stomach. 
 
 The pancreas (^pan'hre-as} is an organ. Its work is to 
 make a fluid which is sent through a little tube into the 
 
42 
 
 PHYSIOLOGY 
 
 intestine, where it helps to digest the food. The pancreas 
 is a glandular organ. Glandular organs are composed of 
 many tubes lying close together. Each tube is surrounded 
 
 by cells set together like blocks 
 in a pavement. Figure 17 
 shows a very simple gland. 
 The pancreas is composed of 
 many hundreds of crooked 
 tubes, all lined with cells which 
 make the digestive fluid. 
 
 SYSTEMS OF ORGANS 
 
 flfl. 17. — Diagram illustrating 
 the plan of a gland. A, cells 
 which line the gland ; B, blood- 
 vessels; C, connective tissue. 
 [From Miller's Histology.] 
 
 We have been studying or- 
 gans. We found that the stom- 
 ach is a digestive organ ; the 
 intestine is a digestive organ, 
 and the pancreas also. There 
 are other organs which assist in digestion : the mouth, 
 with its teeth, tongue, and salivary glands, prepares the 
 food for swallowing ; the esophagus (e-sof a-gus) is the 
 tube which carries the food to the stomach. Then 
 the stomach and intestine hold the food while it is being 
 digested by the fluids made in the stomach, intestine, and 
 pancreas. All of these organs work together in the prep- 
 aration and digestion of food, and we call them collectively 
 the Digestive System. 
 
 In a similar way there are numerous organs which all work 
 together to carry the blood all over the body. All of these 
 organs taken together are called the Oiroulatory System. 
 
 The organs which work together to bring oxygen into 
 the body and carry the carbon dioxide out of the body 
 make the Respiratory System. 
 
REVIEW OF CELLS, TISSUES, AND ORGANS 43 
 
 Remember that the general kinds of work — the gen- 
 eral functions — of the body are performed by systems 
 comprising several different organs ; that each organ has 
 a particular part of a general function to perform ; that 
 every organ is composed of tissues ; and that each tissue 
 assists the organ to do its work. 
 
 HYGIENIC CONDITIONS OF THE CELLS 
 
 In every normal cell is to be found matter in three con- 
 ditions — the matter that is actually living, that which has 
 lived, and that which is about to live. To maintain these 
 three states there must be constant activity, a constant 
 merging of the first state into the second, and the second 
 into the third. Anything that interferes with this activ- 
 ity interferes with the health of the cells, with the work 
 they have to do, and with the vitality of the tissues which 
 they compose. 
 
 The cells cannot work actively if deprived of a sufficient 
 amount of the oxygen of the air. Whoever sits or sleeps 
 in close, unventilated rooms decreases the healthful activ- 
 ity of the cells. Whoever takes an insufficient amount of 
 exercise does the same thing, because, this leads to a slug- 
 gish flow of the blood which brings oxygen to the cells. 
 
 Some substances, when brought into contact with the 
 living matter of the cells, stimulate or increase their ac- 
 tivity, other substances check this, and others stop it 
 altogether. The checking, if continued, results in the 
 death of the cell. A few cells may die without causing 
 the death of the tissue. 
 
 The effect of various substances upon the living cell 
 may be watched under a microscope. If bathed with a 
 proper food substance, the cell may be seen to expand and 
 grow and move more actively. If bathed in an astringent 
 
44 PHYSIOLOGY 
 
 substance like tea, it shrinks up into a ball, and ceases its 
 movements until restored. If bathed with a liquid con- 
 taining a very small proportion of alcohol, its activity will 
 cease, and, unless the proportion is very small, it cannot 
 be again revived. 
 
 Plant protoplasm is so much like animal protoplasm as 
 to render it likely that what will injure the one will injure 
 the other also. Alcohol, in even small proportions, does 
 injure plant protoplasm. 
 
 The London Lancet for June 16, 1900, quotes Dr. J. 
 J. Ridge as saying that healthy cell life, both of plants 
 and of animals, is impossible in the presence of minute 
 quantities of alcohol. This is because the cells cannot 
 tlien take in enough oxygen, and cannot cast out the 
 waste matter from their bodies. 
 
 " Even in extremely minute proportions, alcohol pre- 
 vents or retards the sprouting of seeds, and kills or stunts 
 the growth of the seedlings that are developed. As small 
 a proportion as one of alcohol in eight hundred of water 
 will have a powerfully poisonous effect. The moderate 
 drinker of alcohol dissolves in his blood, and by means of 
 the blood conveys to the living active cells of his brain, 
 liver, kidneys, and other organs, a much greater propor- 
 tion than one in eight hundred, at least once and often 
 several times each day.'"i 
 
 " Alcohol exerts an exceedingly harmful action on rap- 
 idly growing tissues, interfering with their nutrition, and 
 preventing the development of their proper action. In 
 .old age, when the tissues are on the down grade, and are 
 subject to various degenerations, alcohol, in most cases, 
 merely accelerates the process of decay." ^ 
 
 1 Professor William Carter, M.D. 
 
 ••i Professor G. Sims Woodhead, Cambridge, England. 
 
REVIEW OF CELLS, TISSUES, AND ORGANS 45 
 
 Tobacco injures the cells of the body by making them 
 less active. 
 
 When we review what has been said about what alco- 
 hol does to living cells, we find : — 
 
 (1) The living matter in the cells of plants requires the 
 same things for its healthy action as does the living 
 matter in the cells of animals. 
 
 (2) What will injure growing plant cells will usually - 
 injure growing animal cells. 
 
 (3) Alcohol as found in whisky, rum, wine, brandy, or 
 beer, even when very much diluted, will stop all healthy 
 activity, and growth of sprouting plants. 
 
 (4) In the same way, alcohol in its various forms, and 
 much diluted, will stop, or at least injure, the healthy 
 activity of the cells of a young persoii. 
 
 (5) Alcohol is injurious to healthy cells, tissues, and 
 organs of both plants and animals, old or young. 
 
 REVIEW OF CELLS, TISSUES, AND ORGANS 
 
 1. Plants and aninials are composed of tiny particles of living sub- 
 stance. These particles are of various shapes and sizes, and are called 
 Cells. Some cells are spherical, some are dylindrical, some are thin 
 and flat, some are threadlike. 
 
 2. Cells are composed of Protoplasm which is made up of a network 
 of living, moving Cell plasm, whose meshes are filled with the watery 
 Cell lymph. 
 
 3. The Cell must have food to eat and air to breathe ; it can feel 
 and it can moce. The cell is small when young; it grows, and works, 
 and finally dies. 
 
 4. Cells are grouped together in Tissues. Some stand side hy side 
 like the blocks in a pavement ; some overlap like the shingles upon a 
 roof, and some are woven together like the threads in a fabric. 
 
 5. Tissues form Organs. Each Organ has a special work to per- 
 form ; and the tissues assist in doing the work. 
 
 6. Organs are grouped into Systems of Organs. 
 
CHAPTER III. — THE NERVOUS SYSTEM — HOW 
 THE DIFFERENT ORGANS, ARE MADE TO 
 WORK IN HARMONY 
 
 1. THE NEED OF HARMONY IN THE WORKING OF 
 THE ORGANS 
 
 We haye found that the plant or animal body is a 
 colony of cells. We have found that, like a colony of 
 men, some of the individuals (cells) have one kind of 
 work and some another. Another verj-^ important point 
 of resemblance between the two colonies is the need for 
 harmony of action between the different individuals (cells) 
 of the colony. 
 
 When there are only a few hundred individuals in a 
 human colony, there is always some central controlling 
 agency. It may be a patriarch, a chief, a sheik, a king, a 
 czar, or a president, but in every case there is a controlling 
 head to make decisions as to what to do next. This princi- 
 pal controlling agency is always supplemented by a body 
 of individuals whose work is to assist in making decisions, 
 or to announce the decrees or decisions to remote parts of 
 the colony. 
 
 If a community of people were without these most 
 important functionaries, there would be no harmony of 
 action in time of need or of danger. Who has not seen 
 an excited company gathered at the burning of a neighbor's 
 house — everybody giving orders which nobody obeys ; 
 everybody busy, but little or nothing accomplished. 
 
 40 
 
THE NERVOUS SYSTEM 47 
 
 Presently a captain of police or head of a fire company 
 appears upon the scene ; he is experienced in the control 
 of fires and of men. He begins to command ; everybody 
 gives heed and obeys. There is unity of action, tliere is 
 harmony in the means used, both in the time of doing a 
 particular thing and in the extent to which any particular 
 work shall be done. 
 
 Think how impossible it would be to accomplish the 
 work of a great railroad company, if there were not a 
 central office in which plans are laid, decisions made, and 
 commands issued. Through immediate and explicit obe- 
 dience to these commands every individual, and every 
 group of individuals employed by the company work 
 together harmoniously for the accomplishment of the 
 important work which they are undertaking. 
 
 In a strikingly similar way the great number of cells 
 (individuals) which make up the human body must be 
 controlled by some central power, or they will work at 
 cross purposes. 
 
 Suppose the stomach should make the digestive fluid at 
 a time when there was no food in the stomach, and suppose 
 the glands of the mouth which make the saliva should not 
 work when the mouth was chewing the food. Then sup- 
 pose after the chewed food started down the esophagus, 
 that tube should stop contracting ; the dry food would 
 stick in the esophagus and have to be washed down with 
 water. But the stomach, having already made its fluid, 
 and passed it on into the intestines, would be dry, so that 
 the food wQuld be moistened only by the water which 
 came into the stomach with it. Then the food would not 
 digest, but would ferment in the stomach and would make 
 the person sick. 
 
 So we see the absolute necessity of having some con- 
 
48 PHYSIOLOGY 
 
 trivance for controlling tlie action of all of the organs, 
 systems of organs, tissues, and cells. When this control 
 is perfect, the body remains in good health ; but when 
 some portion of the body, even if it be ever so small a 
 portion, fails to obey the commands issued by the central 
 governing organ, the whole system is likely to become 
 deranged and the body become sick. 
 
 The central governing organ of the human (or other 
 animal) body is the brain. The brain is assisted by the 
 spinal cord which lies within the backbone, and by vari- 
 ous organs which collect news for the* brain and carry the 
 messages for it. The brain with the spinal cord and the 
 nerves makes the general nervous system. 
 
 2. THE GENERAL STRUCTURE OF THE NERVOUS 
 SYSTEM 
 
 In bringing harmony of action among those who work 
 for a great railroad corporation, a great army, or other 
 large community of individuals having common interests, 
 two things are necessary ; (1) a central controlling power; 
 and (2) communication from the center to all of the dis- 
 tant parts of the company, army, or community. 
 
 In controlling the movements of trains upon a railroad 
 system, messages are sent along telegraph wires to con- 
 ductors hundreds of miles away, directing them what to 
 do in order that there may be no accident. If something 
 unexpected happens in some part of the system, a message 
 is sent to the controlling center, where action is taken to 
 adapt the movements of trains to the new conditions. 
 
 In a strikingly similar way the animal body possesses a 
 central controlling power in the brain. The brain is in 
 constant communication with all parts of the body. Mes- 
 
THE NERVOUS SYSTEM 49 
 
 sages are continually being sent to all parts of the system. 
 Telegraphic messages are sent over -wires ; the brain sends 
 and receives its messages over fibers which are as fine as 
 as those of a spider's web. 
 
 The telegraph wire is not a part of the telegraph opera- 
 tor, but the nerve fiber is a part of the operator whose 
 station is in the brain or spinal cord. This opi^rator is a 
 nerve cell. The brain and spinal cord are composed of 
 nerve cells with their fibers. Every nerve cell has long 
 fibers over which it sends messages aAvay to other nerve 
 cells, and every nerve cell lias at least one nerve fiber 
 or arm (most have several) through which it receives 
 messages. 
 
 When several telegraph wires are to go side by side for 
 a long distance, they are frequently hound together into a 
 cable. In a similar way the nerve fibers which leave any 
 one part of the brain or cord to go to the same general 
 region of the body are bound together into a cable or, as 
 it is called, a nerve trunk. Nerve trunks contain, not sev- 
 eral only, but many hundreds of the fine nerve fibers. 
 Along the course of the nerve trunk branches are given 
 off, which distribute the nerve fibers to different muscles 
 and organs or to different parts of the skin along the 
 course of the main trunk. 
 
 Figure 18 shows the general form and distribution of 
 the nervous system. The brain, within the skull, is the 
 controlling center. The spinal cord, which passes down an 
 arched-over canal in the vertebral column, consists mostly 
 of nerve fibers wliich carry messages to and from the nerve 
 cells of the brain. There are relay stations all along the 
 spinal cord where messages are received and sent out on 
 their way to and from the brain. 
 
 All of the white lines branching off from the spinal cord 
 hall's phys. — 4 
 
50 
 
 PHYSIOLOGr 
 
 Fig. 18. — The nervous system. ^ , cerebrum ; B, cerebellum; C, the sciatic 
 nerve truuk, giving off branches as it passes down the leg. 
 
THE NERVOUS SYSTEM 
 
 51 
 
 represent trunks of 
 nerves which lie be- 
 tween the muscles or 
 under the skin of the 
 body and limbs. But 
 tliere are also nerve 
 trunks which pass from 
 the spinal cord inward 
 to the body cavity, to 
 the thorax and abdo- 
 men. Tliere is a double 
 line of ganglia along the 
 back side of the body 
 cavity. A ganglion is 
 a relay station made 
 up of numerous nerve 
 cells. These ganglia 
 are about as large as a 
 pea or bean. Each of 
 the ganglia in the dou- 
 ble row, mentioned 
 above, receives a bun- 
 dle of fibers from the 
 spinal cord. Some of 
 these fibers bring mes- 
 sages to the ganglia 
 from the brain or spinal 
 cord, while, some of 
 them carry messages 
 from the ganglion to the 
 brain or cord. 
 
 Each ganglion in the 
 chain sends out nerve 
 
 Fig. 19. — The sympathetic nervous system. 
 Note the hranches (/, II, III, etc.) from 
 the spinal cord to the row of little globular 
 masses or ganglia. A corresponding row- 
 on the right side sends branches to the 
 large central ganglia of the abdomen, the 
 splanchnic (s) , and the mesenteric (m) . 
 
52 PHYSIOLOGY 
 
 trunks to organs of the thorax or abdomen, or to large 
 ganglia in the midst of the abdomen. These large central 
 ganglia serve a purpose similar to that of tTie central 
 exchange of a telephone system. They serve to put the 
 organs into either direct or indirect communication with 
 each other. Through this direct or indirect communication 
 the activity of one organ is responded to by a correspond- 
 ing activity of another. For example, the presence of 
 food in the stomach stimulates the stomach to begin to 
 make the churning movements, and t-o form the digestive 
 fluid. This activity of the stomach causes the pancreatic 
 gland to begin its work of making digestive fluid for the 
 intestine to use in its digestive work. This nervous 
 communication between the different organs of the body 
 enables them to work together toward common ends har- 
 moniously. Because of this sympathetic communication 
 between the internal organs which these nerves and 
 ganglia make they are together called the sympathetic 
 nervous system. Remember, however, that the sympa- 
 thetic nervous system is simply a part of the general 
 nervous system. 
 
 Through the influence of the sympathetic nervous sys- 
 tem, the derangement or disease of one organ may cause 
 the derangement or disease of other organs. 
 
 3. REFLEX ACTION AND HABIT 
 
 In the previous lesson we learned that there are relay 
 stations along the spinal cord. A message sent from the 
 brain to the muscles of the arm starts from a nerve cell 
 in the brain and follows its fibers down the spinal cord 
 to a place opposite the shoulders, where the fiber ends in a 
 little tuft of branches which lie among the short branches 
 
THE NERVOUS SYSTEM 53 
 
 of a nerve cell in the cord. The message is communicated 
 from the branches of the fiber from the brain to the short 
 branches of the nerve cell in the cord, and this cell sends 
 the message along its fiber to the muscles. If the message 
 tells the muscle on the front of the forearm to contract, 
 the fist will double up. When one's brain sends such a 
 message as that, one is conscious of it. Furthermore, one 
 knows it before the brain sends out the message ; so that 
 one can send it or not just as he chooses. 
 
 This kind of action is called Voluntary Action, because 
 one may do it or not just as one wills. 
 
 Why does one will to make a certain motion ? Suppose 
 one were hungry and had before him a piece of food. 
 The eyes, and perhaps also the nose, \Srould send messages 
 to the brain; that is, one would see and smell the food. 
 These sensations in the brain would arouse a desire for 
 the food. Messages would be sent to and fro from one 
 cell to another in the brain ; that is» one would begin to 
 think about the food and his need for it, and finally, per- 
 haps in a very few moments, one would decide to take the 
 food. Messages would be sent to various muscles ; the 
 arm would be extended, the food gra.sped, the arm flexed, 
 and the food carried to the mouth, which would be opened 
 to receive it. This is a very brief aad imperfect descrip- 
 tion of all that takes place in the nervous system under 
 such conditions. To describe it accurately and completely 
 would require many pages. Before one stops to tliink 
 about it, however, it seems to be the simplest thing in the 
 world ; so simple, in fact, that a little baby too small to 
 talk or to walk will perform every portion of the series of 
 motions with faultless accuracy and grace. 
 
 Let us take another example. Suppose that one takes 
 hold of a very warm iron poker, one end of which is in 
 
54 PHYSIOLOGY 
 
 the fire. There are nerves of sense in the skin of the 
 hand ; messages are sent along the fibers to nerve cells 
 which lie just outside of the spinal cord. From the cell a 
 fiber carries the message into the cord and communicates 
 it to another cell which carries it to the brain. When 
 the message reaches the brain, one becomes conscious of 
 the heat of the poker. Let us suppose that the heat is 
 sufficient to make one iincomfortable, and fear that the 
 hand may be burned if the hand is not removed. Mes- 
 sages will be sent down the cord to the proper muscles, 
 and the hand withdrawn. There we have another ex- 
 ample of voluntary motion following sensation. 
 
 Now when the message of sensation' enters the cord on 
 its way to the brain, it follows a branching fiber, only one 
 portion of which goes to the brain. The other portion 
 passes across the cord, directly or indirectly, and com- 
 municates with the nerve cells which control the muscles 
 of the arm and hand. 
 
 Suppose one touches a very hot object, the message 
 which is sent to the cord on its way to the brain is 
 instantly communicated across the cord, and the nerve 
 cell of motion, without waiting to hear from the brain, 
 sends the message back to the arm, causing it to contract 
 and remove the hand from danger. This saves time and 
 frequently decreases the danger done to a part of the 
 body. 
 
 An instant later the brain is fully conscious of all that 
 has happened. One knows that the hand has been burned, 
 and that it was jerked away before the brain was con- 
 sulted ; but one always approves of the action. 
 
 This intervention of the cells of the spinal cord in cases 
 of emergency is called reflex action. But the term has a 
 somewhat wider application than simply to cases of 
 
THE NERVOUS SYSTEM 66 
 
 emergency. When one is learning to perform a new 
 movement or series of movements, such as walking, skat- 
 ing, riding a bicycle, writing, and playing a musical 
 instrument, each movement is a voluntary one.^ The 
 whole attention is required to direct the movements of 
 the body and its different parts. Each movement is likely 
 to be very slow and awkward. After the movement has 
 been made hundreds of times it requires less attention, 
 and the motions are more graceful and accurate. Finally, 
 one may make long series of motions without giving them 
 any attention whatever. Walking, skating, cycling, 
 writing, or playing a piano or violin, eventually become 
 quite automatic or mechanical. 
 
 4. REFLEX ACTION AND HABIT (continued) 
 
 Let us understand exactly what automatie motion is. 
 The will and the thought are usually involved in auto- 
 matic movements, but in quite a different way from that 
 which is observed in the beginner who must study the 
 details of every movement made. The practiced musi- 
 cian reads a measure or phrase of his score and wills to 
 execute it as a whole, while the fingers fall into place 
 more or less automatically to correspond with the thought 
 in the mind of the player. In a similar way, the writer 
 thinks words, leaving the making of each word largely to 
 the fingers. This is especially true of the shorter and 
 more frequently used words. Th.e less familiar and 
 longer words require some attention. Writing with a 
 typewriter becomes automatic in the same way and to the 
 same degree ; so also the use of the t'elegraph instrument. 
 
 lot course the one who finds himself on skateslor on a bicycle for the first 
 time is likely to make a good many involuntary motions, hut they are extra 
 and not necessary, though they may be a usual part of the beginner's exercise. 
 
56 PHYSIOLOGY 
 
 What is the difference between the first labored efforts 
 and the final automatic regularity, speed, grace, and accu- 
 racy? Practice has made one movement suggest the 
 next, and once the combination of movements is willed 
 and the series of movements begun, all of the details of 
 the series become reflex and are performed by the cells of 
 the spinal cord. 
 
 There is no one property of our systems of greater value 
 to us than the reflex action. If it were not for this, we 
 should have to give every step our whole attention. In 
 fact, one could never learn to do anything gracefully, 
 accurately, and rapidly. One would always be like an 
 awkward, halting beginner. 
 
 Very much like this automatic action of the muscles, 
 depending upon reflex action, is a certain property of the 
 nervous system which we call habit. 
 
 Webster defines habit as " the involuntary tendency to 
 perform certain actions, which is acquired by their fre- 
 quent repetition." Further, " Habit' is an internal princi- 
 ple which leads us to do easily, naturally, and with grow- 
 ing certainty, what we do often." 
 
 A study of this definition of habit must make it clear 
 that it cannot be very different from automatic action. 
 Both are acquired gradually ; both make it certain that a 
 particular series of acts will follow a particular act or 
 thought, unless the will power of the brain is used to 
 stop it. 
 
 Habit has a wider meaning than automatic action, and 
 includes thoughts as well as muscular acts. One may cul- 
 tivate a habit of generosity, and a habit of erect carriage 
 while walking. One may cultivate habits of industry and 
 habits of courtesy; habits of honesty and habits of gen- 
 tleness. 
 
THE NERVOUS SYSTEM 57 
 
 Every important function of the body and mind may be 
 diverted from the course for which it was intended by 
 nature ; it then becomes as great a curse as it was a bless- 
 ing when rightly used. So it is with habit. One may 
 get a habit of stinginess, and a habit of slouchy carriage 
 while walking. One may get habits of laziness and habits 
 of impoliteness ; habits of dishonesty and habits of cruelty. 
 
 For every good habit there is a corresponding bad one. 
 During youth one is always acquiring good habits or bad 
 ones. One must do one or the other ; he has no choice in 
 the matter. Good habits are a safeguard during all sub- 
 sequent life; bad habits are persistent enemies. It re- 
 quires years of constant effort to root them out after they 
 are once established ; but it is very easy to keep them out 
 in the first place. 
 
 HOW THE ORGANS ARE CONTROLLED — REVIEW 
 
 1. The body is a colony or community of individual cells. Every 
 colony or community must be controlled, or the individuals will not 
 work in harmony, and little will be accomplished. 
 
 2. The Brain is the central controlling power of the body. Like 
 a telegraph station it has operators and conductors (wires). The 
 operators are Nerve Cells, and the conductors are Nerve Fibers. 
 
 3. The Brain receives news from various parts of the body, the eyes, 
 the ears, and the skin. The Brain sends messages to all parts of the 
 body, —to the muscles, the stomach, and th^ heart. 
 
 4. If one wishes to do something and then does it, we call the 
 action a Voluntary Action. 
 
 5. If the spinal cord answers a message from the skin, causing 
 muscles to move befo'-e the brain knows what has happened, we call 
 the action a Reflex Action. 
 
 6. If one performs an act many times, it becomes automatic or 
 habitual. Automatic and habitual acts are likely to be done without 
 thinking. Habits ai-e formed in this way. 
 
CHAPTER IV. — NARCOTICS — THEIR NATURE, 
 THEIR CLASSES, AND THEIR GENERAL 
 ACTION UPON THE SYSTEM 
 
 When we come to study the different S3''stems of 
 organs, as the digestive system or the circulatory system, 
 we shall study not only the way in which the organs act 
 when properly cared for, but also the various things which 
 injure the organs. Among the things which injure tlie 
 body, one of the most important is the use of narcotics. 
 Let us devote a few lessons to the study of these sub- 
 stances. 
 
 1. NARCOTIC DRINKS 
 
 Narcotic drinks are those that dull the senses, and 
 weaken and unsteady the muscles. 
 
 All alcoholic drinks come under this head. They are 
 usually called stimulating drinks, because their first effect 
 is an apparent stimulation. But they are more often 
 taken for the dulling of the sensibilities which follows 
 and lasts longer. It is the narcotic property which dulls 
 the senses and produces this after-effect. 
 
 It has recently been discovered that what has always 
 been taken for the stimulating effect of alcoholic drinks, 
 is really caused by the narcotic effect upon the self- 
 restraint. Alcohol is not a stimulant. 
 
 In the growth of the race from barbarism to civilization 
 there has gradually come to be a restraint upon the 
 
 58 
 
NARCOTICS 59 
 
 meaner traits, those which cause one to be boisterous, 
 uncouth, and passionate. This restraint, being the last 
 trait acquired, is the weakest and most easily attacked. 
 The first effect of an alcoholic drink is to dull the power 
 of restraint, and a person feels excited, which in reality 
 means that he cares less what he does ; the next effect is 
 to dull the senses. 
 
 No one training for feats of skill requiring strength 
 and accuracy is allowed the use of narcotics. 
 
 Alcohol is a clear liquid which looks like water, but 
 which burns with a blue flame, giving great heat and 
 little light. 
 
 I 
 
 Fig. 20. — The yeast plant, strongly magnified (from Landois and Stirling). 
 1, isolated yeast plants; 2, 3, gemmatioD ; 4, formation of eadogonidia or 
 spores ; 5, budding of spores. 
 
 Alcohol is the result of fermentation. If one adds 
 yeast to a dilute solution of sugar, the yeast will change 
 the sugar to carbon dioxide and alcohol. 
 
 The yeast which produces alcohojic fermentation is a 
 minute plant which grows especially well in sugar water. 
 If one were to look at yeast plants through a microscope, 
 he would find that they are spherical and live either 
 singly or joined together in chains called colonies (Fig- 
 20). The principal food of this plant is sugar, which 
 the plant breaks up in order to obtain the energy it con- 
 tains. This breaking up of the sugar produces carbon 
 
60 PHYSIOLOGY 
 
 dioxide and alcohol, which the yeast throws off as waste 
 products. If we watch the mixture of sugar, yeast, and 
 warm water, we can see the bubbles of carbon dioxide 
 escaping. The alcohol remains in the mixture. 
 
 In bread making we have a similar process. The 
 starch of the flour or the free sugar which is added to 
 it is attacked by the yeast and changed into carbon 
 dioxide, which, in escaping from the sponge or the 
 dough, causes the bread to bubble and become light. 
 The alcohol remains in the mixture until it is baked, 
 when the heat drives it off. If the bread is not suf- 
 ficiently baked to kill the yeast, the growth goes on and 
 the bread becomes sour. 
 
 When water is heated to the boiling point (212° Fah- 
 renheit), it rapidly changes to steam or water vapor, 
 which collects in little bubbles on the bottom of the kettle 
 or other receptacle. The bubbles rise to the top of the 
 water, escape into the air, and float away in a little misty 
 cloud. When alcohol is heated, a similar change takes 
 place, but it does not need to be heated nearly so hot 
 before the escape of alcohol vapor begins. When alcohol 
 and water are mixed together, as would be the case if the 
 alcohol has been made through fermentation of sugar 
 water, or fruit juice, the alcohol may be driven off by 
 heating the mixture hot enough to vaporize the alcohol 
 without vaporizing the water. 
 
 By thus heating the mixture of alcohol and water hot 
 enough to boil or vaporize the alcohol, but not hot enough 
 to vaporize the water, the alcohol vapor will leave the 
 water. If this vapor is caught and conducted through 
 pipes which are kept cold by cold water, tlie alcohol 
 vapor will condense again into the liquid form, and can be 
 caught as it runs from the end of the pipe or tube. 
 
NARCOTICS 61 
 
 How similar this process is to something you have 
 studied in your geographies ! The sun warms the sur- 
 face of the ocean, of lakes, and of other collections of 
 water exposed on the earth's surface ; the water is vapor- 
 ized, and rising, floats away in the form of fleecy clouds. 
 Presently these clouds pass over a range of snow-capped 
 mountains, or pass a current of cold air. The vapor is 
 condensed and falls as rain upon the surface of the earth. 
 
 In this way the water is separated from the briny solu- 
 tion of the sea ; in a similar way men separate one liquid 
 from another when the two liquids vaporize at a different 
 temperature. 
 
 The process of separating one liquid from another by 
 vaporizing with heat and condensing the vapor with cold 
 is called distillation. 
 
 Men distill water from an impure or briny mixture in 
 order to obtain perfectly pure water for use in the chemi- 
 cal laboratory or for use in manufacturing. Men distill 
 alcohol from a mixture of various substances dissolved in 
 water in order to get' pure alcohol for use in various 
 laboratories, for use in manufacturing, or for use by 
 druggists in the preparation of medicines. 
 
 Many of the alcoholic drinks are prepared by distilla- 
 tion. They contain a much larger proportion of alcohol 
 than the original fermenting mixture. Whisky, brandy, 
 and rum are all distilled liquors, and contain 40 per cent 
 or more of alcohol. 
 
 2. FERMENTATION AND DISTILLATION 
 
 All the alcoholic drinks are first fermented, and many 
 of them go no further than this process. Among those 
 which are made by simple fermentation are beer, wine, 
 and cider. 
 
62 PHYSIOLOGY 
 
 In the beer making process, corn, or more commonly 
 barley, is put into a damp, warm place and allowed to 
 stay until it sprouts. We remember that in our study 
 of the corn plant we found that, when the seed began to 
 grow, the starch of the kernel was changed to sugar. 
 As soon as part of the starch has been changed to sugar 
 and dissolved out with water, hops and yeast are added, 
 and fermentation takes place. In this condition it is 
 bottled if it is to be used as beer, but if at this point it is 
 put into a still and the alcohol driven off and caught, it 
 makes whisky. If to the whisky certain flavors are added 
 a drink called gin is made. 
 
 When sugar cane is fermented and distilled, the dis- 
 tilled product is called rum, and when wine is distilled, 
 the product is called hrandy. 
 
 Whisky, gin, rum, and brandy are called ardent spirits, 
 and are as much as one half alcohol. 
 
 Pure wine contains from five to sisteen parts of alcohol 
 in a hundred, but the wine that is obtained in the market 
 often contains as much as one fourth (25 per cent) 
 alcohol. 
 
 Beer and cider contain from four to fourteen parts of 
 alcohol in a hundred. 
 
 Alcohol is the same wherever it is found, and the main 
 difference in the effect of different alcoholic drinks upon 
 the system is due to the difference in the amount of alco- 
 hol which each contains. Three glasses of some cider 
 contain as much alcohol as one glass of strong wine or 
 the same glass filled with one quarter whisky and three 
 quarters water, and an alcoholic habit can be acquired 
 from cider drinking or wine drinking" as well as from beer 
 or spirit drinking. 
 
 The great transformation which tak.es place in the juice 
 
NARCOTICS 63 
 
 of grapes as a result of fermentation is thus strikingly 
 summed by Professor Gaule, of the tJniversity of Zurich, 
 Switzerland : " Between the sweet juice of the grape which 
 does not intoxicate and the intoxicating wine which the 
 drinker loves, a foreign element has entered, fermentation ; 
 that is, the life process of a little fungus — yeast — which 
 feeds upon the juice of the grape and rejects the wine. 
 That which we drink as wine has no more to do with 
 grape juice than, for instance, the ajrowroot (starch) of 
 the plant has with the carbonic acid of the air on which it 
 lives. The one as well as the other is a product of a 
 chemical change which is brought about by the life pro- 
 cess of an organism, though, to be sure, in quite the oppo- 
 site sense, for the green plant cell glorifies that which it 
 consumes, in that it forms from dead substances, carbon 
 dioxide and water, a great source of power (sugar), while 
 the yeast cell does exactly the opposite, consuming sugar 
 and robbing it of most of its power, and casting out as 
 waste substances carbon dioxide and alcohol." 
 
 FALLACIES CONCERNING BEER 
 
 Beer has been called " liquid bread " from the idea that 
 because it is made from grain, as is bread, it is therefore 
 nourishing. In Germany this idea has found expression in 
 the saying that " where the brewery is, no bakery is needed." 
 
 A saloon keeper in England once advertised his beer as 
 "liquid bread." A member of the British Parliament 
 had a chemist examine it. Two per cent was really food. 
 Five per cent was alcohol, and the reipaining ninety -three 
 per cent was water. 
 
 Let us look into this claim a little more closely. Ac- 
 cording to standard analyses, lager beer contains: — 
 
64 PHYSIOLOGY 
 
 89.75 % water, .15 % carbonic acid, 
 
 5.10 % alcohol, 5.00 % malt extract. 
 
 The malt extract, which is the only part that could be 
 said to have nutritive value, consists of malt, sugar, dex- 
 trin, a very slight quantity of albuminous matter which 
 has escaped the processes designed for separating it out, 
 and some bitter principles and volatile oils. All that is 
 nourishing in this could be purchased in bread for one 
 tenth what it costs in beer. 
 
 The healthy grown person requires daily from four hun- 
 dred and fifty to five hundred grammes of the kind of food 
 that is represented in this extract in the beer. To get 
 this amount one would have to drink eight quarts of beer, 
 which would contain about nine ounces of alcohol. The 
 poisonous effect of this amount of alcohol would very 
 quickly show itself. 
 
 Professor Rosenthal of Erlanger says, "Beer is not a 
 food, but a luxury. Let a man drink much beer, enough 
 to make the amount of nourishment in it of value, and the 
 other influences produced by such a quantity will become 
 manifest to such a degree as to cast the factor of nourish- 
 ment in the background. If he drinks little beer, the 
 food value is not appreciable." 
 
 The claim is also made that the food substances in beer 
 are " pre-digested," because they are in soluble form ready 
 to be absorbed. Supposing there were enough of this 
 " pre-digested " food in beer to be of sufficient importance 
 for consideration, whatever advantages to digestion there 
 might be in its being " pre-digested " are offset by the fact 
 that beer retards the digestive process. 
 
 To say that substances like beer or alcohol do not need 
 to be digested because they are already " pre-digested " is 
 
NARCOTICS 66 
 
 only saying that they are in a condition to pass through 
 the walls of the alimentary canal into' the blood. This is 
 no recommendation if it is their nature, when they reach 
 the blood, to do harm, as is the case with beer and other 
 alcoholic liquors. 
 
 Although certain " light beers " may contain only a 
 srnall quantity of alcohol, they are by no means harmless 
 " temperance drinks," as is sometimes urged. The London 
 Lancet of April 1, 1899, asked, " Does the consumption of 
 more beer really mean the consumption of less spirit ? " 
 and answered the question by saying, in substance : Few 
 physicians will admit such an opinion. We certainly 
 know of no instance in which a spirit drinker was saved 
 by the drinking of more beer. The remedy, if not worse 
 than the disease, is but one shade better. Beer drinkers 
 afe by no means free from the vice of spirit drinking, and 
 are certainly not seldom the victims of the same diseases 
 of the kidneys and liver as those which are likely to 
 afflict the drinkers of ardent spirits. 
 
 3. THE GENERAL EFFECT OF NARCOTIC DRINKS UPON 
 THE SYSTEM 
 
 Alcoholic drinks seem to be at first stimulating, and 
 later to have a dulling effect. 
 
 This stimulation is, however, not re'al, but only seeming, 
 and is caused by the dulling of the power of self-restraint. 
 
 A civilized man restrains himself; he does not allow 
 himself to say certain things, or to do certain things ; he 
 does not hoot and howl, he does not laugh immoderately 
 nor weep at trifles, because he restrains himself. The dull- 
 ing effect of a narcotic first acts upo*n this self-restraint, 
 and a person becomes boisterous, loud, and rude. He ta,lks 
 hall's phys. — 5 
 
66 PHYSIOLOGY 
 
 too much, and is not considerate in his treatment of others. 
 As this dulling goes on, it affects his senses and other 
 mental powers, so that he is not clear in his thoughts, and 
 later it affects his muscles, causing him to reel and stagger. 
 
 The thing about wine and cider which is hard for young 
 people to understand is, why there is harm in anything 
 made from grapes and apples, which are both healthful 
 fruits. But since we have seen how quickly sugar can be 
 changed to other substances by the yeast plant, it will not 
 be so hard to understand. If one puts a few spoonfuls 
 of grape jelly or of marmalade into a pint fruit jar, fills it 
 with warm water, and adds a little yeast, he will find in a 
 few hours that it is fermenting. The sugar is being 
 changed to carbon dioxide and alcohol. In three or four 
 days the liquid will have changed into wine or cider, and 
 if it is put into a still, alcohol pure enough to burn at the 
 end of the tube may be distilled off from the liquid. 
 
 The juice of apples as it is pressed from the fruit is 
 harmless and refreshing, but it remains so only for a few 
 hours, after which it contains a little alcohol, which in- 
 creases day by day, so that cider which at first was harm- 
 less comes very soon to be a little harmful, and in a few 
 weeks to be intoxicating, as it then contains almost if not 
 quite as much alcohol as beer contains. 
 
 Some think that there is no harm in drinking cider and 
 beer. Professor Meyer, of the University of Gottenburg, 
 says : " Naturally the lighter alcoholic drinks, such as 
 cider, beer, and light wines, cultivate a taste for the 
 stronger liquors and ardent spirits. Those who make 
 statements to conflict with the undoubted facts of statis- 
 tics must either be ignorant of these facts, or else they 
 at'tempt to pervert them in order to apologize for their 
 own drinking habits." 
 
NAKCOTICS 67 
 
 Some people tliink that alcoholic drinks may be indulged 
 in moderately. Let us hear what medical men of this 
 country and of other countries have to say about mod- 
 erate drinking. " Every drunkard was once a moderate 
 drinker, and every man who, by his example, leads other 
 men to moderate drinking, also leads a part of them to 
 immoderate drinking. He starts a stone rolling which it 
 is no longer in his power to arrest." ^ 
 
 "After opening the floodgate not one man in a thousand 
 can stay the progress of a besetting vice, and of all beset- 
 ting vices the alcohol habit is the most inevitably progres- 
 sive. An unnatural appetite has no natural limits. "^ 
 
 " Experience has proved that recovery from drunken- 
 ness is possible only by complete abstinence from alcohol. 
 Moderation does not help, for the taking of a small 
 quantity of liquor causes an inordinate thirst for 
 
 more 
 
 "3 
 
 " Alcoholic indulgence extinguishes control. How 
 many a pathetic story could I tell of even great and 
 good men, the intellectual, high minded, and moral, 
 who, confident in -their power of ktfowing when to stop, 
 have at last helplessly succumbed and been disgraced. " * 
 
 The effect of alcohol upon a grown up person is 
 bad enough ; but it is even worse upon a developing 
 person. The effect upon children is worse, because the 
 body and brain of the child are in thg process of growth. 
 Even in the years of early manhood, alcohol is very harm- 
 ful to the proper development of body and mind. Dr. 
 
 ^ Professor G. von Bunge, Professor of Physiological Chemistry, University 
 of Basel, Switzerland. 
 2 Felix Oswald, M.D. 
 
 8 The Lancet, London, June 8, 1895, p. 1468. 
 * Charles R. Francis, in The Medical PioneeT. 
 
68 PHYSIOLOGY 
 
 G. H. McMichael says : " During the years of adoles- 
 cence, while the brain is only partially developed, the 
 nervous organization is not in the stable condition which 
 marks the full vigor of normal, adult manhood. This 
 being so, the desire for alcoholic drinks is much more 
 easily acquired between the ages of seventeen and 
 twenty-five than in later life." 
 
 4. THE GENERAL EFFECT OF NAJICOTIC DRINKS, 
 
 , ESPECIALLY ALCOHOLIC DRINKS, UPON 
 
 THE SYSTEM 
 
 I. ALCOHOL A POISON 
 
 Bbfojbe we can properly study alcohol as a poison, we 
 must know what a poison is. A poison is any substance 
 which, absorbed into the blood, is capable of injuring the 
 body, either by causing damage to the tissues or by 
 producing functional disturbances. From this definition 
 we see that a poison may disturb the mode of action of 
 the tissues or organs without causing permanent damage 
 to these structures, or a poison may injure the system by 
 changing the structure of the tissues. AUbut's " System 
 of Medicine" says, alcohol "acts ditectly on the nerves 
 as a functional poison," and Professor Woodhead says : 
 " Alcohol exerts an exceedingly deleterious action on 
 rapidly growing tissues, interfering with their nutri- 
 tion, and preventing the development of their proper 
 function. In old age, when the tissues are on the down 
 grade and are subject to various degenerations, alcohol in 
 most cases merely accelerates the process of decay." 
 
 Professor Pick, of the University of Wurzburg, in Ger- 
 many, defines a poison as any substance which, being mixed 
 with the blood, causes a disturbance in the functions of 
 
NARCOTICS 69 
 
 any organ, and adds, "that alcohol is such a substance 
 cannot be doubted." He calls the attention of his 
 countrymen to the fact that " the English language 
 appropriately calls the disturbance caused by alcoholic 
 drinks intoxication, which by derivation vaea-ns poisoning." 
 Professor Forel, of the University of Zurich, Switzer- 
 land, says : "Alcohol, even when diluted, as in wine, beer, 
 and cider, is a poison which changes the active tissues of 
 the body, causing them to become fatty, either by having 
 fat deposited in them or by the chEinging of the tissues 
 themselves to fat. Even in such small amounts as a glass 
 of wine or a pint of beer taken with meals, it is injurious 
 because it injures the brain by dulling its activity and 
 deranging its functions. This has been clearly demon- 
 strated by the experiments of numerous investigators. ^ 
 The most moderate drinking of alcoholic beverages is 
 quite useless for anybody, and by means of the example 
 produces very great injury to the people in general, 
 because many will be led to drink who would not other- 
 wise have done so, and of the many who begin as moderate 
 drinkers, few will remain moderate drinkers." 
 
 II. INFLUENCE OF ALCOHOL UPON THE BODY 
 
 " France presents a splendid illustration of a country 
 whose inhabitants made free use of alcoholic drinks, begin- 
 ning usually with light wines. And as a result, this great 
 country, with its beautiful climate, its fertile soil, and other 
 material advantages, equal to the most favored portion of 
 the earth, at the present time actually depends upon immi- 
 gration to keep up the numbers of its population. The 
 leading men of France are seriously studying the ques- 
 
 1 Such investigatois as Kraepelin, Smith, Fiirer, Aschaffenburg, and others. 
 
70 PHYSIOLOGY 
 
 tion, ' How to prevent the depopulation of France ? ' The 
 French nation, descended from a race of gigantic Gauls, 
 who struck terror to the hearts of their enemies by the 
 very magnificence of their presence, has declined to such 
 a degree from the stunting influence of alcoholic and simi- 
 lar drinks upon their growth, that the average height of 
 the people at the present time is actually less than that 
 of other civilized nations. The facts witnessed in wine 
 growing districts and in wine growing countries certainly 
 do not commend the universal use of wine as a remedy for 
 intemperance — a use for which it has been suggested." ^ 
 
 According to Dr. Brunon, the population in Brittany is 
 being rapidly decreased through the. use of alcohol. Alco- 
 hol has become a part of the regular table supply of the 
 home. Coffee and beer, or some other alcoholic drink, 
 form the basis of the dinner ; and if one of these mast be. 
 omitted, it is the coffee. The most distressing feature of 
 the case is the serious effect that this use of alcohol has on 
 the young. The death rate of young children is very great, 
 such as is met with nowhere else.^ 
 
 The Consular Reports of 1895 quote a writer in Le Havre 
 as saying, — 
 
 " Alcoholism is the great misfortune of the present day, 
 and if the evil is not corrected, France will be changed 
 into a nation of brutes by this ignoble vice. The peril is 
 evident, and it is high time to check jt. I know that the 
 infamous vice is not peculiar to our country, but I see that 
 its ravages are greater here than elsewhere." 
 
 " The workingmen, women, and children of our coun- 
 try absorb, in its various forms, a poison which filters 
 
 1 J. H. Kellogg, M.D., Journal of Medical Temperance Association, Octo- 
 ber, 1897, p. 12fi. 
 
 2 From the Normandie Medicale, quoted in Medical and Surgical Seporter. 
 
NARCOTICS 71 
 
 through their bodies, which, even in small doses, daily re- 
 peated, breaks the strength, paralyzes the nervous system, 
 destroys the intelligence, and makes the drinker grow 
 prematurely old. It makes in a few years, sometimes 
 even in a few months, of an individual once robust, active, 
 and a valuable member of society, a b^ing abject, degraded, 
 and infirm. This poison is alcohol."^ 
 
 By strict persistence in total abstinence and hygienic 
 living the children of drinking parents may overcome the 
 tendency to defective conditions of body and mind, to 
 which they are especially liable. A weak will with which 
 to resist temptation is frequently part of the inheritance 
 which children receive from alcoholic parents. But even 
 such a will may resist the first glass, and in this way gain 
 strength for continued resistance of temptation as well as 
 uprightness of character in all directions. 
 
 5. OTHER NARCOTICS 
 I. TOBACCO 
 
 CiGAKS, cigarettes, smoking tobacfco, chewing tobacco, 
 and snuff are all made from the dried leaf of the tobacco 
 plant. 
 
 Tobacco contains a sharp-tasting liquid called nicotine, 
 which is a quick-acting and deadly poison. Because of 
 this poison, the juice of the tobacco is never purposely 
 swallowed ; but in chewing, the saliva dissolves the nico- 
 tine, and a part of it is absorbed into the system ; while in 
 smoking, the nicotine in the smoke and vapor is absorbed 
 
 1 A. Motet, M.D., of Paris, Member of the French Academy of Medicine, in 
 an address before the VI International Congress against the Use of Alcoholic 
 Liquors. Eeport of Proceedings. 
 
72 PHYSIOLOGY 
 
 by the saliva and the moist membranes of the mouth and 
 nose, and taken into the system, where it exerts all of its 
 harmful effects, among which is an irritation of all the mem- 
 branes with which it comes in contact. After a time, the 
 narcotic effect dulls the sense of feeling, so that the irrita- 
 tion, while it still exists, is not felt. This poison in the 
 system makes one less able to throw off disease, and some 
 of the best insurance companies arg refusing to insure 
 tobacco smokers. 
 
 The cigarette, being a cheap preparation, tempts boys 
 to indulge more in this than in any other form of tobacco. 
 While tobacco is injurious to every one, it is far more 
 harmful to those who are growing. All physicians agree 
 in saying that a boy who uses tobacco can never be so 
 large or well-developed a man as he could have been with- 
 out it. He can never have the strength of body nor the 
 vigor of mind that he would have had except for the use 
 of tobacco. 
 
 All physicians agree in saying that no one should begin 
 the use of tobacco before the age of eighteen or twenty 
 years. If a boy waits to that age before beginning its use, 
 the chances are his judgment will be sufficiently matured 
 to keep him from it. 
 
 II. OPIUM 
 
 There are other narcotics that have a medicinal value, 
 that have also the power of creating a, desire for the drug, 
 which in its increasing use is fatal. Such drugs are 
 opium, the dried juice of the white poppy ; morphine, a 
 white powder made from opium ; and laudanum, a solu- 
 tion of parts of the opium in alcohol. A habit of using 
 any of these narcotics is almost impossible to break, and 
 its effects are very serious. 
 
OPIUM 73 
 
 Paregoric is a weak form of opium in alcohol, and 
 should be taken only by prescription from a physician. 
 
 Soothing syrups also contain opium, and should not be 
 given to children, as they do not cure but simply stupefy 
 the child. 
 
 What has been said in the preceding lessons about the 
 influence of alcohol upon the will power, applies with 
 equal truth to such narcotics as tobacco and opium. The 
 enslaving influence of opium is even greater than that of 
 tobacco or alcohol. 
 
 The secret of the power of these things over a person 
 who has become addicted to them is that they rob the 
 person of a part of the will power, and will power is 
 the very thing that is required in order to enable the 
 victim to break the habit. 
 
 In the chapter on the nervous system, we found that a 
 habit is a blessing, if a good one, and a curse, if a had one, 
 because the habit is made possible only through a change 
 in the nervous system. When the habit has once been 
 formed, it requires many months, perhaps years, to break 
 it. It requires the constant exercise of the will power. 
 How is one to fight a habit on equal terms, if through 
 the habit he has been robbed of a part of his fighting 
 equipment ? 
 
 Young men who are in training for athletic contests 
 where strength, alertness, skill, and accuracy are required, 
 are positively forbidden by the managers of the teams to 
 use tobacco or any other narcotic, and boys and young 
 men entering the employ of a great business house or a 
 corporation where their success depends upon strength, 
 alertness, skill, and accuracy, as well as integrity and 
 industry, would surely reach a much higher success if 
 they abstained totally from all narcotics. 
 
74 PHYSIOLOGY 
 
 REVIEW OF NARCOTJCS 
 
 1. Narcotics are substances wliich dull the isenses and the sensibili- 
 ties. The most common narcotics are the Alcoliolic Drinks, Tobacco, 
 and Opium. 
 
 2. Alcoholic drinks are made by Fermenting sugar with yeast. The 
 yeast eats the sugar and throws out carbonic acid gas and alcohol as waste 
 matter. 
 
 3. Drinks whicii are prepared by the fermentation of fruit juices 
 or of grain sugars are called Fermented Drinks; examples are, wine, 
 cider, and heer. 
 
 4. Drinks which are prepared by the distillation of the fermented 
 liquors are called Ardent Spirits; examples are, whisky, brandy, gin, 
 and rum. 
 
 5. Alcoholic drinks seem to stimulate at first because they dull the 
 brain control and the self-restraint. 
 
 6. Alcoholic drinks dull all of the senses and all of the sensibilities, 
 weaken the will power, and create a thirst for more alcohol. 
 
 7. The moderate use of alcohol is very likely to lead to the im- 
 moderate use of it. 
 
 8. The immoderate use of alcohol causes disease, degradation, 
 misery, and crime. 
 
SPECIAL PHYSIOLOGY 
 
 Under General Physiology and Hygiene we have 
 studied briefly the physiology of a plant ; we have 
 studied the cells and tissues of which the organs and 
 systems of organs are built up ; we have studied the 
 means by which the organs are controlled and made to 
 work together harmoniously ; and we have studied some 
 of the more important things which harm the body through 
 injury to the tissues or through derangement of the func- 
 tions. 
 
 We are now prepared to enter upon a detailed study of 
 each system of organs of the human body. This part 
 of physiology is called Special Human Physiology. 
 
 75 
 
CHAPTER v. — NUTRITION — HOW THE BODY 
 IS NOURISHED 
 
 The term Nutrition is used in physiology to include all 
 of the work that tissues and organs do in the Preparation 
 of Food for absorption, which includes Mastication, Swal- 
 lowing, and Digestion, the Absorption of food and the 
 Assimilation of food, under which head one studies how 
 food material is built up into the li"\(ing active tissues of 
 the body, as well as the oxidation df food material and 
 of tissue material. One may, under the head of Nutri- 
 tion, study Foods, as well as those parts of domestic econ- 
 omy which deal with the choice and preparation of food. 
 
 1. WHY WE EAT 
 
 If you have ever watched a locomotive in motion, you 
 must have seen the fireman putting fuel into the firebox. 
 You know just as well as the fireman does that if he should 
 stop putting coal on the fire the engine would stop going. 
 He knows something which you do ngt know, and that is, 
 how much coal to put on to make the engine go a given 
 distance. 
 
 Many railroad companies and many large factories 
 analyze coal from different companie's before they buy, in 
 order to know which coal will give the most heat and 
 motion per ton or per dollar's worth. 
 
 The amount of heat and motion which a fuel produces 
 can be exactly measured. The coal which is used in the 
 locomotive becomes oxidized and changed into carbon 
 
 76 
 
NUTRITION 77 
 
 dioxide and water, with smoke and ashes left over. The 
 oxidation of the carbon of the coal causes the heat to be 
 given off. The heat under the boiler produces from the 
 water steam, whose pressure in the cylinder moves the 
 piston and turns the wheels. The engine itself is not 
 built up by the fuel which it consumes, and it gradually 
 wears out. 
 
 We take food into our bodies to supply heat and motion, 
 and if the food be tested we can tell exactly how much 
 heat and motion it will give. In the experimental station 
 at Washington and in many laboratories, men are at work 
 finding how much energy can be obtained from different 
 foods when prepared in different ways. 
 
 Food will give the same amount of heat and motion 
 when burned in a furnace as when consumed in the 
 body. 
 
 If the government wished to move an army of men 
 from one city to another, it could either feed the men on 
 nourishing food and give them a long time in which to 
 walk there, or it could use the same food in an engine, 
 which would carry the men on a train in much less time. In 
 this case some extra food must be given the men to keep 
 them warm, as the heat which would be enough to do this 
 is lost from the engine. Bread is, however, too bulky to 
 carry and too expensive to burn, so instead of bread we 
 use in a locomotive a fuel like coal,^ which takes up less 
 room and costs less. 
 
 A loaf of bread burned in a furnace and one consumed 
 in the body give out exactly the same amount of heat and 
 motion. The food which we consume is changed into 
 fluid form, and then goes to build up tissues just as it 
 does in the plants. 
 
 In selecting coal, the buyer chooses that which gives the 
 
78 PHYSIOLOGY 
 
 most power for the money, without regard to the looks of 
 the coal or the color of the flame. 
 
 In choosing food to supply our bodies with heat and 
 motion, what should we think of first ? Should it not be 
 the amount of power it contains ? In other words, food 
 should be chosen to give the most nourishment for the 
 least money, provided it can be made to look well enough 
 to be appetizing and taste well enough to be palatable. 
 Here comes in the work of the cook, who can choose and 
 prepare the food, and add the seasoning and the decoration. 
 
 We should think an engineer very wasteful if he used 
 more coal than is necessary to make his engine do the 
 work he needs. Is it not equally wasteful for us to eat 
 more than we need for our work siniply because it tastes 
 good and we enjoy it ? 
 
 That which is harmful should not be eaten, although we 
 may like it. That which is nourishing should often be 
 taken, even though we do not like it. If one thinks of 
 the good which a wholesome and nourishing food will do 
 the body, instead of thinking whether the taste is most 
 pleasing to him, he may readily cultivate a real liking 
 for a food which might at first seem distasteful. 
 
 2. WHAT WE EAT — FOODS 
 1. EGGS AND MILK 
 
 Wb have decided that food shall be chosen first for the 
 energy it contains, and to do that best we must know of 
 what different foods are composed. 
 
 Let us look first at the egg, for in this we have what is 
 to the animal world just what the peed is to the plant 
 world. If we examine an egg carefuljy, we find an outside 
 shell that corresponds to the shell of a nut. Underneath 
 
NUTRITION 79 
 
 the shell we find a tough skin like the skin that covers all 
 seeds ; inside the skin a white fluid and a yellow fluid 
 which are the food, and just under the very thin skin 
 of the yellow jjart or yolk we see a white spot with a 
 ring around it, which is the germ or young chick. The 
 young chick is surrounded by the food which it will need 
 when it wakens to life, just as the young plant is. Both 
 the plant germ and the chick germ are sleeping proto- 
 plasm. They sleep until the heat wakens them to life. 
 The seed needs also moisture to soften the food, but the 
 egg is already supplied with water enough. 
 
 The yolk of the egg is so balanced that the germ spot is 
 always up whichever way the egg is turned. In this way 
 the germ is kept next to the heat which the motlier hen 
 supplies from her body when she sits on the eggs. The 
 yolk of the egg is proteid and oil, with some mineral 
 matter. The oil gives it the yellow color. The white of 
 the egg is pure albumen, or proteid with mineral matter 
 and water. 
 
 From these materials are built up the bones, muscles, 
 blood, nerves, and feathers of the chicken. 
 
 The egg is nature's food for young birds. Is it a good 
 food for us ? We need bones, muscles, blood, nerves, and 
 hair, and if the egg will build up these tissues in a bird, it 
 will also build them up in us. It is, however, such con- 
 densed food that it cannot be used alone for the food of 
 ah adult, and not at all, or at most sparingly, for a child 
 under one year old. When the egg is raw, it is easily 
 digested, but when cooked, it becomes hardened and is 
 more difficult to digest. 
 
 Nature has supplied in milk a food for the young of 
 higher animals. This food exactly fills the need of the 
 young child, and contains everything that a child requires 
 
80 PHYSIOLOGY 
 
 for its first year's growth. Let us see what materials milk 
 contains. The part that makes it liquid is water, the 
 sweetness comes from sugar, the cream which rises to 
 the top is oil, and the rest is proteid and mineral matter. 
 You can see that milk alone would sustain life for a long 
 time. 
 
 II. BXPBKIMBNTS 
 
 You still have a supply of iodine obtained for the experi- 
 ments in plant physiology. Some of the iodine has its 
 original strength, while some is diluted. 
 
 Get from the druggist or from a physician a few ounces 
 of Fehling's Solution (composed of a mixture of copper 
 sulphate, or blue vitriol, and potash). 
 
 Get also a few four inch or six inch test tubes. They are 
 made of thin annealed glass, and may be heated in a flame 
 without danger of breaking. If there are no Bunsen gas 
 burners in the school building, a common kerosene lamp 
 can be used with good results. 
 
 1. Take a few drops of albumen or white of egg in a 
 test tube, dilute it with a spoonful of water, and heat it 
 over a flame. It will soon begin to turn white and to 
 thicken, or coagulate, as it is called. 
 
 2. Take a spoonful of milk and heat it in a similar way. 
 It will not coagulate. 
 
 3. To a spoonful of milk add a few drops of lemon 
 juice or any other acid. The milk wjll coagulate. 
 
 The small masses which separate out from the milk are 
 called coaffula, and consist of casein, the principal proteid 
 of the milk. When milk is heated, one may notice a thin, 
 wrinkled membrane collecting upon its surface. This 
 membrane consists of albumin (milk albumen), which is 
 the other proteid of the milk. 
 
NUTRITION 81 
 
 The yellowish part of the milk which can be drained 
 away from the casein coagula is the whey. Whey consists 
 of water, milk sugar, and mineral matter, with perhaps 
 some cream or fat. Most of the fat stays with the casein 
 when it separates out in coagula. 
 
 4. Put into a test tube as much grape sugar (dextrose) 
 as will stay on the tip of a penknife blade, add a spoonful 
 of water to dissolve it, add an equal amount of Fehling's 
 Solution, bring the mixture to a boil over a flame, and 
 notice the orange or brick-red, heavy precipitate which 
 first clouds the mixture, then settles to the bottom of the 
 tube. This is copper oxide, which separates out of Fehl- 
 ing's Solution when that is heated with a solution of 
 dextrose, or of milk sugar (lactose), or of malt sugar 
 (maltose) . 
 
 5. Put a spoonful of whey into a tube, and add an equal 
 amount of Fehling's Solution. Heat it over a flame, and 
 note the separation of the copper oxide, again showing the 
 presence of dextrose, or lactose, or maltose. In this case 
 it was lactose, or milk sugar. So milk contains proteid, 
 sugar, and fat. 
 
 3. WHAT WE EAT 
 I. CEREALS 
 
 Grains which are used for food are called cereals. They 
 belong to the grass family, and form an important part of 
 our food. 
 
 Corn, wheat, oats, barley, rye, and rice are cereals, and 
 from these we get corn meal, cornstarch, wheat flour, 
 graham flour, oatmeal, barley, rye flour, rice flour, and 
 various other meals, flours, and prepared "breakfast 
 foods." 
 
 hall's PHI'S. 6 
 
82 PHYSIOLOGY 
 
 If we look at a grain of each of the; cereals, we find they 
 all have a skin covering the grain. The oats, barle)', and 
 rice have a tough, chafflike skin, which is always removed 
 before it is put on the market for food. Barley and rice 
 are so seldom seen with the skin on that we think of them 
 always as white grains. 
 
 Under the skin of the wheat and rye, oats and barley, 
 is a brownish or yellowish coat that is very rich in proteid 
 and mineral matter, while the inner part of the seed is 
 starch containing some proteid and mineral matter. At 
 the end of the kernel and on the opposite side from the 
 long groove we find the germ, which is of protoplasm and 
 very nourishing. 
 
 Most of the proteid part of these small grains, especially 
 wheat, is a sticky substance called gluten, and it is this 
 gluten which makes many of the wheat breakfast foods 
 seem sticky when cooked. In white wheat flour we have 
 the starch with some gluten and mineral matter. In 
 "whole wheat " or " entire wheat " we get the starch and 
 all the gluten and mineral matter from the brown coat, as 
 it is not bolted ; and in graham flour we get all the con- 
 tents of the grain and the skin as well. There is no 
 nourishment in this skin, but it makes the flour coarse, 
 and thus excites or stimulates the formation of digestive 
 fluids, as well as the movements of the stomach and intes- 
 tine. 
 
 It is sometimes said that white bread is not nourishing ; 
 that you can see is not the fact, but you can see equally 
 well that the whole wheat and graham flour is much more 
 nourishing to the whole body, and especially to the bones 
 and teeth, as the greater part of the mineral matter lies 
 in the brown coat which is bolted out of the white flour. 
 Growing boys and girls need much of the bone making 
 
NUTRITION 83. 
 
 material to be found in whole wheat and graham flour, 
 in the cereal breakfast foods and in corn meal. 
 
 Great care should be taken in the preparation of cereal 
 foods, for unless they are well cooked they are hard to 
 digest, and some of the nourishment is lost. Some of 
 these cereals are said to need two minutes' or fifteen 
 minutes' cooking, but in every case the food is much im- 
 proved in wholesomeness by at least thirty to forty minutes' 
 cooking. 
 
 II. EXPERIMENTS 
 
 Soak some grains of corn, wheat, Oats, rye, barley, and 
 rice in warm water for two or three days. 
 
 1. With a penknife and a strong aeedle dissect off the 
 thick, husky, outside shell of a kernel of oats and barley. 
 
 2. Dissect off the thin, transparent skin of corn, of 
 wheat, and of rye. Find the germ of each kernel. Make 
 some thin slices across each kernel, and draw a figure 
 showing the location of the germ, and the food material 
 which the parent plant stored for the sleeping young 
 plant. 
 
 3. Place a slice from each grain into a few drops of the 
 dilute iodine in a watch crystal, and notice the blue color, 
 showing both the presence of starch and its location in 
 the kernel. Notice that the germ and that part of the 
 kernel in its immediate vicinity do not turn blue, and, 
 therefore, contain no starch. 
 
 4. Put slices of each grain into strong iodine, and after 
 they have been acted upon for several minutes, rinse off 
 the iodine. Notice that the starch is turned to a very dark 
 blue and the germ and its surrounding food material to a 
 brownish yellow. Strong iodine turijs proteid matter this 
 color. The oil is mixed in with the starch and proteid, 
 
84 PHYSIOLOGY 
 
 and is not so easily skown by a simple experiment. If a 
 kernel of grain be burned, a small amount of ashes remain- 
 ing will represent the mineral matter. 
 
 Remember that cereals contain staa-ch, proteid, oil, and 
 mineral matter. 
 
 4. WHAT WE EAT (continued) 
 I. VEGETABLES 
 
 In our study of the cereal foods we found that they 
 contain all the kinds of nourishme^it. They alone can 
 sustain life. There is another class of foods which we call 
 legumes. These are the beans, peas, and lentils. These 
 also are rich in proteid and starch, and have some oil, 
 mineral matter, and cellulose, and like the cereals form a 
 perfect food, but in such condensed form as to need some- 
 thing else to help them through the digestive tract. 
 
 There is still another class of foods which gives nour- 
 ishment in a much less condensed form and provides the 
 variety Avhich we need to give relish to our food. This 
 class includes the vegetables. 
 
 Let us taste a bit of beet, turnip, parsnip, carrot, and 
 of onion, and in all of them we shall notice a sweet taste. 
 These vegetables we eat for the sugar they contain, and 
 for the mineral salts, which we cannot detect by taste. 
 They contain also a large amount of cellulose, which has 
 no nourishment, but which, by stimulating the digestive 
 organs, helps them in their work. If we taste a piece 
 of white or sweet potato, we shall notice that it is rough 
 to the tongue and has a raw taste. This is due to the 
 presence of starch. The sweet potato has some sugar in 
 addition to the starch. 
 
 All of these vegetables which contain starch or sugar are 
 
NUTRITION 8/) 
 
 very nourishing, but cannot be used alone as food, as they 
 have almost no proteiJ and oil. Because of this lack of 
 these substances, many vegetables are prepared with milk 
 and butter in the cooking, and are in this way supplied 
 with oil and proteid. 
 
 Such vegetables as cabbage, lettuce, celery, spinach, and 
 other greens are used largely as a relish, and contain 
 almost no nourishment, They are, however, very impor- 
 tant as a relish, and some of them have other uses. Let- 
 tuce and celery have a juice that is soothing to the nerves, 
 while spinach and other greens contain more iron than do 
 other vegetables. 
 
 Besides these vegetables, there are some vegetable prod- 
 ucts that are very valuable as food stuffs. Among these 
 are potato starch, cornstarch, arrowroot, sago, and tapioca, 
 which are almost pure starch. The first is the extracted 
 starch of the potato, the second of the corn kernel, while 
 arrowroot and tapioca are from the underground stem of 
 tropical plants. Sago is from starch deposited in the 
 trunk of the sago palm. 
 
 The vegetable products that are pure sugar are beet 
 sugar, cane sugar, grape sugar, maple sugar, molasses, 
 and syrups. All sugars and syrups, with molasses and 
 honey, are very nourishing and for most people very 
 wholesome. 
 
 As potatoes contain principally starch, we usually add a 
 little butter and milk to them or eat them with meat and 
 gravy. Milk and butter are also often added to beans, 
 peas, parsnips, carrots, cabbage, celery, and onions. 
 
 Macaroni, which is made from flour and water and con- 
 tains as much proteid as wheat supplies, is still largely 
 starch, but when cooked with milk, butter, and cheese 
 contains all the elements of food. 
 
86 PHYSIOLOGY 
 
 II. EXPEKIMENTS 
 
 1. Make a careful dissection of a soaked bean, and of a 
 pea, making a drawing to show the thin skin and the two 
 halves of the kernel, which represent the seed leaves. 
 Find the tiny stem and rootlet of the germ plant. 
 
 2. Make thin slices of the soaked kernels and treat 
 them with dilute and with strong iodine, and note the 
 results. 
 
 3. Make thin slices of turnip, p'arsnip, carrot, and 
 onion, and test one kind of vegetable at a time by put- 
 ting a slice into a test tube with a spoonful of water and 
 of Fehling's Solution. Heat to boiling over a flame, and 
 notice that the slice turns a brick-dust red or orange, 
 showing the presence of sugar (dextrose). 
 
 4. Test the same vegetables with dilute and strong 
 iodine, and notice that there is no starch and no proteid, 
 except perhaps, a little proteid just under the skin. 
 
 5. Test slices of white and sweet potato for sugar and 
 for starch and proteid. Note results. 
 
 5. WHAT WE EAT {continued) 
 I. PRUIT 
 
 All the foods we have talked about, with the exception 
 of milk and eggs, have been vegetable products, and the 
 fruits also belong here. Among the many fruits, we find 
 some much sweeter than others. These are eaten largely, 
 for the sugar they contain and their healthful effect upon 
 the digestion. Such fruits are apricots, peaches, pears, 
 plums, cherries, grapes, and some apples. Bananas are 
 rich in sugar, but lack the refreshing juices of the other 
 fruits. 
 
NUTRITION 87 
 
 Oranges, many apples, quinces, aijd crab apples are 
 chiefly valuable for their acid, although they also contain 
 sugar. '' 
 
 The lemon and lime have no sugar, but are very 
 important foods because of the acid and salts which they 
 contain. 
 
 Fruit is especially needed in the summer weather and 
 in warm climates, while fats are needed in cold weather 
 and in cold climates. 
 
 II. MEAT 
 
 As yet nothing has been said of animal food, and we 
 have already seen that life could be sustained without any 
 animal food, for it contains no new- material. It does, 
 however, contain the most nourishing kind of food in a 
 condition easy to use. Meat is composed of proteid matter 
 and fat, held together by connective tissue, such as bone, 
 gristle, and so forth. We are likely to think that porter- 
 house steak at twenty-five cents a pound is more nourish- 
 ing than other cuts of meat at six or ten cents per pound. 
 If both are broiled, it is true the porterhouse steak will 
 yield more nourishment, but the cheaper meats by long 
 cooking become equally nourishing, because the cooking 
 changes the connective tissue to gelatine, which is proteid 
 food. 
 
 Have you not noticed when the water in which a soup 
 bone has been cooked becomes cold it looks like jelly? 
 That comes from the changed connective tissues of the 
 bone, gristle, etc. Let us make some menus that will 
 contain a healthful variety and yet give all the elements 
 of food at a low price. 
 
88 
 
 PHYSIOLOGY 
 
 MENU NO. 1 
 
 Breakfast. 
 Cereal food. " Milk. 
 
 Luncheon. 
 
 Omelet. Creamed potatoes. 
 
 Brown bread. Appte sauce. 
 
 Dinner. 
 
 Beefsteak. 
 
 Potatoes. Spinach. 
 
 Grapes. 
 
 MENU NO. 2 
 
 Breakfast. 
 
 Soft boiled eggs. Bread and butter. 
 
 Cereal coffee. 
 
 Prunes. 
 
 Pork and beans 
 
 Luncheon. 
 Made dish of rice and meat. 
 
 Bread and butter. 
 
 Dinner. 
 
 Tomato sauce. 
 
 Milk toast. 
 Cold meat. 
 
 CaiTots. 
 
 Potatoes. 
 Sliced oranges. 
 
 MENU NO. 3 
 Breakfast. 
 
 Luncheon. 
 
 Graham bread. 
 
 Dinner. 
 Boiled beef. 
 
 Baked apples with cream. 
 
 Cereal coffee. 
 Sliced potatoes. 
 
 Potatoes. 
 
REVIEW OF Fooris 89 
 
 REVIEW OF FOODS 
 
 ] . Nature's food for the young of higher ahimals is milk. 
 
 2". Nature's food for little chickens or other birds before they are 
 hatched is egg. Eggs and milk contain all that the body needs for 
 its growth and development. 
 
 3. Milk and Egg contain Albumen, or Propid, and Fat, and Water, 
 and Mineral Mailer. Milk also contains Sugar. 
 
 4. The Grains or Cereals contain Starch, Pais, Proteid or Albumen, 
 and Mineral Matter. 
 
 5. Peas and Beans contain starch, oil, mineral matter, and are very 
 rich in proteid. People who eat no meat us*e milk, eggs, and peas or 
 beans freely in order to get enough proteid. 
 
 6. Some fruits are full of sugar and are, therefore, very nourishing : 
 grapes, peaches, plums, cherries, etc. 
 
 7. Some fruits are acid and are refreshing and wholesome in sum- 
 mer : lemons, oranges, apples, etc. 
 
 8. Meats are usually eaten freely though they are not necessary, 
 because the vegetable foods with milk, eggs, butter, and cheese make 
 a sufficient and perfectly wholesome diet. Meats are rich in proteids, 
 fat, and mineral matter. The expensive meats are not more nourish- 
 ing than the cheaper cuts. 
 
 6. THE STRUCTURE OR ANATOMY OF THE DIGESTIVE 
 
 SYSTEM 
 
 The Digestive System consists of the Alimentary Canal, 
 with certain glands whose ducts or tubes open into the 
 canal. The alimentary canal consists of a series of hollow 
 or tubular organs through which the food passes during 
 the process of digestion and absorption. Beginning with 
 the mouth the food passes down the esophagus into the 
 stomach. (Make a careful study of Fig. 21 while reading 
 this description). After it leaves the stomach it passes 
 through the coiled small intestine, which is subdivided 
 into duodenum, jejunum, and ileum. Passing from the 
 
90 
 
 PHYSIOLOGiT 
 
 ileum into the large intestine through a small opening 
 it comes into the coecum, then passes upward, across, and 
 downward through the colon into the rectum. (Compare 
 
 Fig. 22 with Fig. 21). 
 The glands of the 
 digestive system are 
 the three pairs of sali- 
 v,ary glands (theparo- 
 tids, the sublinguals, 
 and the submaxil- 
 laries'), the pancreas, 
 and the liver. The 
 Itver, however, has 
 little to do with di- 
 gestion, and much to 
 do with assimilation 
 and excretion. Let 
 us now look carefully 
 at each of these or- 
 gans of digestion, and 
 see how each is made 
 and what part of the 
 work of digestion 
 each performs. The 
 mouth cavity is 
 formed by the cheeks, 
 the lips, the tongue, 
 and the palate ; the 
 latter has an upper 
 part hai'd and bony, 
 which extends back into a softer part from which the 
 uvula hangs down. Between the Cheeks are the teeth, 
 whose office it is to masticate the food and mix it with 
 
 Fig. 21. — A diagram of digestive system. 
 Par., SI. & Sm., parotid, sublingual, and 
 submaxillary glands; Ph., pharynx; Es., 
 esophagus; V.C, vena cava vein receiving 
 chyle through thoracic duct {Th.d.^ from 
 lacteals {Lc.)\ Lv., liver; P., pancreas; 
 iS., stomach; D.. duodenum; C, caecum; 
 T.Ap., vermiform appendix. 
 
NTJTEITION 
 
 91 
 
 the saliva. There are two sets of the teeth, the tempo- 
 rary set of twenty teeth, which is lost at about six years, 
 and the permanent set of thirty- two teeth (Fig. 23). 
 There are three parts to be distinguished in a tooth : 
 the crown or part seen 
 in the mouth, the root 
 or part which projects 
 into the gums, and the 
 line between which is 
 called the neck. 
 
 The teeth are com- 
 posed of a hard, shiny, 
 outside layer called the 
 enamel, which acts as 
 a protection to tlie 
 teetli, the middle bony 
 part or dentine, and 
 the inner soft part 
 or pulp, largely com- 
 posed of blood vessels 
 and nerves (Fig- 24). 
 
 Beginning in the 
 middle of the jaw, one 
 finds on each side of 
 each jaw two cutting 
 teetI^ or incisors, one 
 tearing tootli or canine, 
 two semigrinding teeth 
 called bicuspids, and tliree grinders or molars. Most of 
 the teeth have a single root, but the molars have two and 
 sometimes three roots or fangs. Tlie saliva, which mixes 
 with the food during the mastication, by tlie teetli, conies 
 from three pairs of salivary glands : the parotid [/land. 
 
 Fig. 22. — Picture of the organs of digestion. 
 a, duodenum, leading out of tlie pylorus; 
 6, liver; c, esophagus; d, pancreas; e, 
 stomach ; /, spleen ; (/, i, j, Tc, m, n, parts of 
 large intestine ; A>,Z, small intestine. [From 
 Johownot and Bonton.] 
 
9£ 
 
 PHYSIOLOGY 
 
 situated iii front of the ear; the submaxillary, situated 
 under the jaw; and the sublingual, upder each side of the 
 tongue. These glands make or secrete the saliva and 
 give it out when stimulated by the presence of food in the 
 mouth, or even by the thought of food. The pharynx is 
 
 supplied with, two 
 doors which prevent 
 the food from getting 
 into the wrong pas- 
 sages. In order that 
 the food may not go 
 into the nasal passage 
 the uvula and soft 
 palate turn back dur- 
 ing the process of 
 swallowing and cover 
 the opening ; and 
 that it may not go 
 into the air tube, a 
 little guard, the epi- 
 glottis, protects the 
 opening of the air 
 passage. This is done 
 very quickly, for dur- 
 ing the process of 
 swallowing one can- 
 not take breath. One 
 does occasionally try to breathe and swallow at the same 
 time, with the result of getting food into the windpipe, 
 causing violent coughing until i^ is expelled. The 
 esophagus is a long tube which has a soft mucous lining 
 and a muscular coat of circular bajids. In forcing the 
 food along the esophagus the muscular bands do not con- 
 
 FiG. 23. — The jaws and the teeth ; 1, 2, incisors ; 
 3, cauine ; 4, 5, bicuspids ; 6, 7, S, molars ; 
 ffl, vein; &, artery; c, nerve; (2, vein, artery, 
 and nerve. [From Johownot and Bonton.] 
 
NUTRITION 
 
 93 
 
 passage 
 
 tract all at once, but in succession, beginning at the 
 pharynx. The first contracts and makes the 
 smaller, and thus pushes 
 the food on to be con- 
 tracted upon by the next 
 band. This motion is 
 called peristaltic action. 
 The same kind of motion 
 carries the food along the 
 whole extent of the ali- 
 mentary canal. 
 
 7. 
 
 OF THE 
 SYSTEM 
 
 ANATOMY 
 DIGESTIVE 
 (continued') 
 
 The Stomach is a pouch 
 which holds about a quart 
 or three pints ; the open- 
 ing between it and the 
 esophagus, being near the 
 heart, is called the cardia, 
 and the one from the 
 stomach into the intes- 
 tines is the pylorus. Both 
 of these gateways are 
 supplied with circular 
 muscles which by con- 
 tracting close the open- 
 ing. The cardiac end of 
 the stomach is the storage part, and the gastric juice 
 secreted by this end is somewhat different from the 
 gastric juice secreted by the pyloric end, which does the 
 work of churning and digesting the proteids (Fig. 25). 
 
 Fig. 24. — Diagram ot the structure aud 
 setting of a normal incisor toofh. 
 [Biidecker.] L, cuticle of enamel ; 
 ^, enamel ; J), dentine with canaliculi ; 
 J, layer between enamel and dentine; 
 £, border-line between enamel and 
 cementum of neck ; S, cementum of 
 neck; Ce, cementum of root; Z, layer 
 between dentine and cementum ; P, 
 pericementum; A, arteriole of pulp, 
 branching into capillaries ; V, vein ot 
 pulp taking up capillaries ; iV, medul- 
 lated nerve-fibres of pulp; £(/, epithe- 
 lium of gum; Fe, periosteum; Ca, 
 bone tissue of alveolus; i'^, papillary 
 layer of gum ; Co, cortical bone of 
 alveolus or socket ; M, spaces of bone. 
 
94 
 
 PHYSIOLOGY 
 
 The stomach has four coats : an cfutside smooth coat, 
 a second muscular coat which enables *the stomach to con- 
 tract and expand, an inner much-folded coat of mucous 
 membrane, and one between this and, the muscular coat. 
 
 Fig. 25. — Inside of the stomach, front view, showing the folds (or rugae) of 
 the mucous membrane. 
 
 which is called the sub mucosa. In the muscular coat the 
 muscles run both lengthwise and crosswise, and by con- 
 tracting first one set and then another of these muscular 
 coats give the stomach a churning motion. 
 
 The inner mucous coat is thrown up in folds when the 
 
NUTRITION 
 
 95 
 
 stomach is empty, but these are flattened out when the 
 stomach is full. 
 
 The gastric glands are situated ih the mucous lining 
 and pour out the gastric juice when food enters the 
 stomach, or when it is in the habit of 
 receiving food (Fig. 26). 
 
 The pancreas is a long spongy organ 
 which secretes the pancreatic juice and 
 empties ' it into the duodenum near its 
 union with the. stomach. The small in- 
 testine has, like the stomach, four coats, 
 but the inner one, in addition to folds 
 similar to those which we noticed in tlie 
 stomach lining, is also pushed up into 
 little fingerlike projections called villi, 
 which very much increase the inner sur- 
 face of the intestine. The food gets 
 into the hollows between the villi and 
 is in this way kept from passing so 
 quickly through ; meanwhile the villi can 
 absorb the digested material. 
 
 The other intestinal juices are secreted 
 by the intestinal glands which lie be- 
 tween the bases of the villi, and as the 
 food is forced along by the peristaltic 
 action of the intestine, it becomes di- 
 gested and is absorbed by the villi (study 
 Figure 27). 
 
 The large intestine is about five feet in length. There 
 is little nourishment left in the food when it reaches the 
 large intestine, so that it consists of refuse and water. 
 This latter is absorbed as it passes along, and the refuse 
 is carried away. 
 
 Fio. 26. — A peptic 
 gland, from cardiac 
 end of stomach. 
 Very much magni- 
 iied. A, central or 
 chief cells, which 
 make pepsin; B, 
 border or parietal 
 cells, which make 
 acid. [From Mil- 
 ler's Histology. '\ 
 
96 
 
 a ^ « 
 
 4L ,% . 
 
 Fig, 27. — A very much magnified picture of a slice tlirough the small intes- 
 tine. [Benda.] Notice the outer strong coat of connective tissue (a), the 
 muscular coat (d lengthwise, and e circular), the suhmucous coat of con- 
 nective tissue (/). The mucous memhrane (A) with two very large folds 
 (jl and B) which run crosswise around the inside of the intestine. (See 
 duodenum, Fig. 25.) Notice the flngerlilie projections (Ji) which cover the 
 whole surface of the mucous membrane, and are so fine and delicate that 
 the surface of the memhrane looks and feels like velvet. Between the 
 fingerlike projections or villi there are little "glands dipping down into the 
 mucous membrane. These intestinal glands are similar to the stomach 
 glands except that they have no border cells. (rSee Fig. 26.) 
 
 8. REVIEW OF ANATOMY OF DIGESTIVE SYSTEM 
 
 1. Name the parts of the alimentary canal, beginning 
 with the mouth. 
 
 2. Name the glands which form a part of the digest- 
 ive system. 
 
NUTRITION 97 
 
 3. Draw a diagram of the digestive system. 
 
 4. How many teeth have you? How many, if any, 
 belong to the temporary set ? How many teeth will be 
 required to complete your permanent set, and when ought 
 they to appear ? 
 
 5. "What provision is made to guide the food on its 
 passage through the pharynx ? 
 
 6. How can one swallow water when the head is lower 
 than the stomach ? 
 
 7. How many kinds of tissue in the wall of the 
 stomach ? What is the work of each ? 
 
 8. What is the advantage of the stomach having a 
 lining larger than the outside wall, thus causing the 
 lining to be thrown into folds ? 
 
 9. What is the advantage of the crosswise folds of the 
 mucous membrane lining the small intestine ? 
 
 10. What are the villi ? What ai-e the intestinal glands? 
 
 11. Of what use is the vermiform appendix? How 
 did man come to have such an organ ? How large is the 
 rabbit's vermiform appendix ? Is this organ useful to the 
 rabbit? Could man live without it? 
 
 9. DIGESTION BY SALIVA 
 
 Wb called plant digestion the process of changing food 
 from a form in which it cannot be used to a form in which 
 it can be used, and the same definition will do for animal 
 digestion. 
 
 Plant digestion is, however, carried on outside of the 
 plant body, while animal digestion goes on within the 
 animal body. The process of animal digestion is so 
 thoroughly understood that it can be imitated outside of 
 the body, and the process watched. 
 hall's thys. — 7 
 
98 PHYSIOLOGY 
 
 We found that plants cannot use starch until it has been 
 changed by a ferment. The same is true for animals ; 
 and as the process goes on within the body, the mouth is 
 supplied with a juice called saliva, which produces this 
 change. Starch can be acted upon by the saliva much 
 more readily after it is cooked, so that all cereal foods, 
 potatoes, and other starchy vegetables, are always cooked 
 before being eaten. 
 
 When the food has been prepared, it is taken into the 
 mouth and masticated. This process of mastication has 
 two purposes : first, to grind it into, small particles that 
 can be reached by the saliva ; and second, to moisten it 
 thoroughly, so that it may be more easily swallowed, and 
 so that it will have enough of the saliva to make the 
 change. 
 
 It is interesting to watch the process of digestion, and 
 to find out just what the change is. Suppose we put into a 
 glass tube a little cooked starch, some saliva, a little water, 
 and then, after shaking it up, hold it in the warm hand 
 for a few minutes. Now, if we put a few drops of iodine 
 in the tube, we shall find no blue color, which proves there 
 is no starch, but a purple color, which iodine always shows 
 in the presence of dextrine, or half digested starch. We 
 could go on and show that there is actually sugar present, 
 after five minutes of warmth upon the saliva and starch. 
 Saliva, then, is a juice whose work is to change starch to 
 sugar. 
 
 EXPERIMENTS 
 
 1. Prepare starch paste by rubbing starch in water to a 
 thin creamy consistency, and boiling until it is clear. 
 
 2. Put into a test tube one fourth teaspoonful of starch 
 paste, a little saliva, and an equal amount of water ; shake 
 
NUTRITION 99 
 
 up the mixture, and hold it in the hand for a few minutes 
 to keep it warm. Add iodine, and- instead of the blue 
 color of the starch, we get a reddish blue color, showing 
 that the starch has been changed (to dextrine). 
 
 3. Mix in a test tube, as before, starch paste, saliva, and 
 water. Keep warm five minutes. Add an equal volume 
 of Fehling's Solution, and heat to boiling. The precipita- 
 tion of copper proves that sugar is present (maltose). 
 
 4. Try these experiments with raw starch, and show 
 that saliva digests cooked starch much more readily than 
 it digests raw starch. 
 
 10. DIGESTION BY THE GASTRIC JUICE 
 
 We found the saliva of the mouth to act upon the 
 starchy foods, changing them to sugar. But as saliva 
 has no effect upon proteid foods, nature has supplied 
 another juice in the stomach to do this work. 
 
 The food, when it is swallowed, takes down into the 
 stomach a quantity of saliva which carries on the starch 
 digestion. The gastric juice of the stomach does not be- 
 gin to flow until after the stomach is stimulated by the 
 presence of food ; and, as it collects slowly, it gives the 
 saliva time to go on with its work on the starchy foods. 
 
 If we test the saliva, we find it alkaline, that is, like 
 soda ; but if we test gastric juice, we find it acid. You 
 know when we put sour milk and soda together, one coun- 
 teracts the other. This is true of any alkali and acid. 
 After enough of the acid gastric juice has collected to 
 neutralize the alkaline saliva, the latter can no longer do 
 any work. Then the gastric juice begins its work upon 
 the proteids. 
 
 During the half or three quarters of an hour in which 
 the saliva can work before the gastric juice has made the 
 
100 PHYSIOLOGY 
 
 stomach too acid, only a small portion of the starchy foods 
 has been digested ; the rest passes on into the intestines. 
 
 If the food has been well cooked and thoroughly masti- 
 cated, so that the gastric juice can get at every particle, 
 the work goes on faster, and with greater ease. 
 
 When we eat sugar, we are relieving the saliva of its 
 work by eating food already changed ; and when we eat 
 peptonized foods, digested proteid food, or peptone, we are 
 relieving the gastric juice of its labor. 
 
 The gastric juice is secreted by the gastric glands (Fig. 
 26). These are in the mucous membrane of the stomach. 
 Those at the cardiac end of the stomach differ from those 
 in the pyloric end in having border cells which secrete 
 acid. The gastric juice contains both acid and pepsin. 
 
 EXPERIMENTS 
 
 Get a pig's stomach from the stockyards, or from the 
 village slaughterhouse. The stomaph of a pig is very 
 similar in size and structure to that of a man. Cut it 
 open, rinse it off, and make a careful study of the coats, 
 and of the mucous membrane. Draw figures, and make 
 a full description in your notebook. 
 
 2. With an old table knife or a strong spoon scrape 
 the mucous membrane of the stomach, saving the slimy 
 scrapings in a pint jar. Add water enough nearly to 
 fill the jar, stir or shake vigorously for several minutes, 
 add the juice of a lemon to take the place of the acid which 
 the gastric glands of the stomach usually secrete. Label 
 this : Grastria Secretion. 
 
 3. Buy five cents worth of pepsin from the druggist, 
 put it into a pint jar, add the juice of a lemon, and fill the 
 jar with water ; shake thoroughly, and label : Artificial 
 Crastrio Juice. 
 
NUTRITION 101 
 
 4. Cut or tear off some fine stringlike shreds from a 
 piece of raw steak. Put two or thiee of these into a 
 test tube with the artificial gastric juice and keep warm 
 for fifteen minutes, noting very carefully all changes. 
 Repeat with gastric secretion. 
 
 5. Digest very soft-boiled egg with the two different 
 preparations of gastric juice. 
 
 6. Try starch paste and a piece of fat to see if gastric 
 juice will digest either. 
 
 11. DIGESTION BY THE PANCREATIC JUICE 
 
 Perhaps you have wondered what became of all the 
 starch which the saliva did not digest, and when you 
 know that gastric juice digests only a part of the pro- 
 teid, and that as yet there has been no effect upon the 
 fats, you will see clearly the need for another digestive 
 fluid. 
 
 When the food leaves the stomach it consists of the still 
 undigested starch, the still undigested proteid, the fats, 
 such sugar as we may have eaten, mineral matter, and 
 •water, besides the dextrine and sugar and peptone which 
 have been formed by the saliva and the gastric juice. 
 These all mixed together make a grayish, soupy mixture, 
 which we call chyme. The chyme leaves the stomach and 
 enters the duodenum, the upmost section of the intestine. 
 Just at the entrance of the intestine is a tube from which 
 the pancreatic juice enters the duodenum, and this juice, 
 with the help of the intestinal juice and the bile, con- 
 tinues the process of digestion. 
 
 The pancreatic juice has three kinds of ferments, each 
 of which has its own particular work. One ferment acts 
 upon starch, changing it to sugar ; one acts upon proteid, 
 
102 PHYSIOLOGY 
 
 changing it to peptone ; and one changes fat into an emul- 
 sion, or into soap, which may readily be absorbed from 
 the intestine. 
 
 The intestinal juice is secreted by the little intestinal 
 glands that are located in the mucous membrane of the 
 small intestine, between the bases of the villi. This juice 
 contains one ferment which has the power of changing 
 such sugars as maltose, lactose, and cane sugar to grape 
 sugar, or dextrose. 
 
 The bile is secreted hj the liver, and assists the pan- 
 creatic juice in making an emulsion of the fats and oils. 
 The bile contains no ferment. The mucus which it 
 contains in abundance lubricates the wall of the intes- 
 tine, and so helps the food to slide along through the 
 narrow canal. 
 
 The combined effect of these digestive juices is quickly 
 noticed on the still undigested food, which is soon in a 
 condition to be used in the body as nourishment. In 
 other words, the food is now digested. 
 
 EXPERIMENTS 
 
 • 
 
 1. Buy from the druggist five cents' worth of Pan- 
 creatin ; put it into a pint jar ; add one quarter tea- 
 spoonful of baking soda (bicarbonate of soda) ; nearly 
 fill the jar with water and shake vigorously. Label : 
 Artificial Pancreatic Juice. 
 
 2. Put into a test tube a few shreds of raw steak or 
 a bit of soft-boiled egg, add a half tube of the pancreatic 
 juice, and see if it will digest either of these in fifteen 
 to thirty minutes. 
 
 3. Put into a test tube a little starch paste, add half 
 a tube of pancreatic juice, shake thoroughly, and keep 
 
NUTRITION 103 
 
 warm fifteen minutes, (a) Take out half of the mixture 
 and test with iodine to see if the starch has been partly or 
 wholly changed to dextrine, (by Take the other half of 
 the mixture ; add an equal volume of Fehling's Solution ; 
 shake to mix ; heat to a boiling temperature and note if 
 any of the starch has been changed to sugar (maltose). 
 
 4. Add to a spoonful of olive oil an equal volume of 
 Artificial Pancreatic Juice ; shake vigorously two min- 
 utes ; note that the oil is changed to a white, milky 
 liquid, an emulsion containing some soap. 
 
 Note that some preparations of pancreatin will digest 
 proteid and fat ; some will digest starch and fat ; while 
 a perfect preparation digests proteid, fat, and starch. 
 
 12. REVIEW OF THE WHOLE PROGESS OF DIGESTION 
 
 1. How many digestive juices are there? Where are 
 they made or secreted ? In what part of the alimentary 
 canal do they do their part of the digestion ? 
 
 2. How many different kinds of food do we eat? 
 Where is each kind digested ? 
 
 3. What is chyme, and of what does it consist ? 
 
 4. How many ferments are at work in the small intes- 
 tine ? What is the work of each ferment ? Into what 
 final form is starch changed ? Proteid ? Fat ? Cane 
 sugar and milk sugar ? 
 
 5. Why do the contents of the small intestine look like 
 milk ? 
 
 6. What is the test for starch ? For dextrine ? 
 
 7. What is the test for sugar (dextrose, maltose, lac- 
 tose) ? What is the reddish substance which separates 
 out in the test ? 
 
 8. What is the name of the ferment of the stomach ? 
 
104 PHYSIOLOGY 
 
 13. THE HYGIENE OF DIGESTION 
 
 Now that we know the elements of food, and what 
 value each has in the building up of the tissues, we are 
 ready to decide the best method of preparing foods, the 
 best time for eating them, and some other points regard- 
 ing food and health. 
 
 In tasting a raw potato or raw rice, we noticed the 
 granular feeling of the starch and the unpleasant taste. 
 If we were to try to digest raw starch in a little saliva 
 we should find it still undigested after fifteen or twenty 
 minutes, while the cooked starch and saliva show dex- 
 trine after one minute. The cooking breaks up the starch 
 grains and allows the saliva and pancreatic juice to reach 
 the starch itself and digest it. 
 
 Therefore, all starchy foods should he thoroughly cooked. 
 It does not follow that all other kinds of food should be 
 much cooked. For example, raw &gg digests very 
 quickly, while egg that has been cooked becomes hard 
 and so compact that the gastric aiid pancreatic juices 
 cannot readily penetrate them to digest them. 
 
 Meat which contains much connective tissue must he cooked 
 for a long time at a temperature just below boiling, that the 
 connective tissue may be rendered in part digestible ; but 
 as a rule, lean meat should be cooked only enough to make 
 it palatable. 
 
 There is much talk about the use of meat, and per- 
 haps it will be well to say that the people who have done 
 the most toward the advancement of civilization have 
 been the meat and vegetable eating people and not the 
 vegetarians. Although the proteids can be obtained from 
 vegetables, there seems to be something else which meat 
 alone can give. The fault then is not in eating meat at 
 
NUTRITION 105 
 
 all, but in eating it too often and in too great quantities. 
 One needs more meat in winter than in summer. Eng- 
 lish and American jjeople eat too much meat. A proper 
 amount of meat makes one active, while too much makes 
 one nervous. People engaged in severe bodily exercise 
 can eat much more meat without affecting the nerves 
 than can be eaten by students or people engaged in less 
 active labor. 
 
 We have seen that starch is an important part of our diet 
 and that before we can use it in building up tissue it must 
 become sugar. The question naturally follows, why do 
 people often say we should not eat sugar nor candy '? Per- 
 haps it will help us to find out if we remember how many 
 of the foods we eat contain starch, %^hich will, of course, 
 make sugar ; and if we also remember that sugar is not 
 a muscle making, but a heat making food. Sugar and 
 candy are nourishing, but if we eat much of them we add 
 too much sugar to our diet and make our stomachs liable 
 to fermentation. 
 
 Then again, such things would do little if any harm to 
 the average person if eaten at the end of a meal, and 
 thus taken at a proper eating time. But they are seldom 
 taken then, and one of the most injurious things we can 
 do is to eat at irregular hours. Why ? Because if we 
 are regular in our meal times, the dig'estive juices become 
 regular in the time that they appear in the stomach and 
 intestine, and at the usual time for eating they will flow 
 freely to do their work. 
 
 If between the meals we take any kind of food, it stim- 
 ulates the juices to flow, and then when we need them for 
 the regular meal, which is heavier and needs more of 
 the juices, they do not flow readily, and the food is not 
 well digested. 
 
106 PHYSIOLOGY 
 
 14. THE HYGIENE OF DIGESTION (continued) 
 
 Having now properly chosen our food and cooked it in 
 the best manner, we are ready to decide when it should be 
 eaten. Certain people tell us to eat no breakfast, others 
 to eat no lunch and still others to eat nothing just before 
 sleeping; but all of these things do not touch upon the 
 fundamental rule of eating, which is : Hat only so much as 
 is needed for nourishment, and eat only at regular hours. 
 
 One of the most frequent causes of overeating is the 
 practice of serving too many things at one meal. In 
 order to eat a little of each thing presented, more is eaten 
 than otherwise would be. This is only one of the draw- 
 backs of the practice of serving a great variety at one 
 meal. When so many things are served at one meal the 
 possible number of things is much sooner used up, and one 
 becomes tired of his food, or, as we say, he loses his 
 appetite. There is also the added expense in money, time, 
 and labor entailed by the addition of unnecessary things. 
 
 Meat is one of the most common articles of diet and we 
 have found that it is rich in proteid. It has been found 
 that the nations which use meat are the best thinkers and 
 the most progressive people. It has also been learned 
 that the people who eat the most meat, the English and 
 Americans, are most subject to such diseases as gout, 
 neuralgia, and rheumatism. Meat gives no food material 
 which cannot be obtained from vegetables, and yet the 
 eating of meat seems to give an activity and agility that 
 vegetable food does not impart. When meat is eaten in 
 large quantities this activity increases until the person 
 becomes nervous, restless, and irritable. 
 
 Those who are doing heavy manual labor can eat much 
 more meat without receiving harm than can be eaten 
 
NUTRITION 107 
 
 by less active people. Those who have rheumatic tenden- 
 cies should avoid the use of lean meat except in small 
 quantities. 
 
 Rich pies, cakes, and puddings you will perhaps think 
 are useful because they contain sugar, eggs, milk, fat, and 
 flour, all of which are nourishing, but unfortunately they 
 are so put together as to make them very hard to digest, 
 and this makes the time required for digestion longer. 
 
 The main thought in the hygiene of digestion is : Eat 
 those things which are for our bodily good, although they may 
 not be the most pleasing to the taste; and avoid those things 
 which do us harm, although they are most to our liking. Eat 
 
 TO LIVE, n^t LIVE TO EAT. 
 
 15. THE HYGIEfTE OF DIGESTION — AVATER 
 
 In the little corn plant that grew from the seed because 
 of the warmth and moisture it had, we found nine parts 
 out of ten to be water. In all plants, from the least to 
 the greatest, we find a large quantity of water. 
 
 Water is nature's drink, intended for all life. It exists 
 in the greatest abundance, and all living things are able 
 to procure it. Rivers, lakes, and springs are nature's 
 reservoirs for storing pure water. Wells and cisterns are 
 man's reservoirs. 
 
 The purest water is that taken from nature's reservoirs 
 where they are not near large cities. When the city refuse 
 empties into a body of water it leaves many impurities 
 and germs of disease. The water must then be taken 
 from far beyond the reach of the impurity or it must be 
 boiled to kill the germs. Rain water is the purest form 
 of water aside from those just mentioned, provided it has 
 not become impure after falling. 
 
108 PHYSIOLOGY 
 
 The artesian well is the most artificial plan of procuring 
 water, and water from such wells is often heavily charged 
 with mineral salts that are not the best for our use. The 
 system is unable to take up and use lime and magnesium 
 salts in this form. They thereforp tend to clog the 
 system, causing a tendency to constipation, or if absorbed 
 entail very hard work upon the kidneys to throw them 
 out of the system. This water is more healthful if 
 boiled ; or better yet if distilled. 
 
 Sugar and salt must have water to dissolve and dilute 
 them before they can be absorbed by the body, hence the 
 desire for drink after eating them. 
 
 All processes of digestion require water to complete 
 them. It is, however, not a good practice to wash food 
 down with water. Let the saliva moisten the food, and 
 let the water be taken, a little at a tioie, when the mouth 
 is empty. 
 
 It is beneficial to take water with the meals and after the 
 meals, but it is not so well to drink it just before the meal. 
 If ice water is used it should not be taken by the half 
 glass but should be sipped, that it may be warmed before 
 reaching the stomach. 
 
 After what has been said of the harmfulness of the 
 lime and magnesium minerals in the water, the question 
 would naturally follow, why then do we use mineral water ? 
 These mineral waters which are used as beverages contain 
 other minerals than lime and magnesium, and have a 
 special medicinal value. Effervescent mineral waters con- 
 tain carbon dioxide under pressure. When the pressure 
 is removed the gas begins to expand and escape, causing 
 the bubbling. The salts of most mineral waters stimu- 
 late the excretory organs, and are usually taken for this 
 purpose. 
 
NUTKITIOif 109 
 
 16. THE HYGIENE OF DIGESTION— DRINKS 
 I. KEFEESHING DKINKS 
 
 Under this heading we may mention first lemonade and 
 other fruit acid drinks, which are so pleasing to the taste in 
 the summer, and really aid in the digestion if taken at the 
 right time. The gastric juice of the stomach is acid, and 
 will flow freely upon the entrance of food into the stomach. 
 But if just before the food is taken we introduce an acid 
 into the stomach, the gastric juice will not flow so freely, 
 and the food is hindered in its digestion. If the fruit 
 acid comes in during the latter part of the meal, after the 
 gastric juice has already flowed, it assists in the digestion. 
 Fruit acid drinks are then better not taken just before 
 or during the early part of the meal. 
 
 Fruit Juices, such as apple juice or grape juice or rasp- 
 berry juice, may be extracted, mixed with a little sugar, 
 boiled to kill all germs, and then bottled to prevent 
 fermentation. These with the addition of a little water 
 also make refreshing drinks. 
 
 Fruit Sirups are fruit juices cooked with enough sugar 
 to keep them from fermenting without sealing. These 
 must be used with a great deal of water, in order to make 
 refreshing drinks. They are more often used as flavor- 
 ings for other drinks. 
 
 Soda water, without flavoring, is simply water and car- 
 bon dioxide, and derives its name from the soda which 
 was originally used in making the carbon dioxide. In 
 this form it may be classed with refrpshing drinks ; when 
 ice cream, milk, or eggs are added, it should rather be 
 classed with the next group. Soda water is usually flar 
 vored with a fruit syrup. 
 
110 PHYSIOLOGY 
 
 II. NOURISHING DKTNKS 
 
 Nourishing drinks, including milk, cocoa, chocolate, and 
 the cereal drinks, such as " postum cereal " and " grano," 
 possess a food value in themselves, and when they are 
 served with cream and sugar become still more nourishing. 
 
 All of these drinks are best taken with the meals, or 
 when food is required, as they demand the work of all the 
 digestive juices to digest them. 
 
 III. STIMULATING DKINKS 
 
 The stimulating drinks, which have no other important 
 properties, are coffee and tea. 
 
 Tea contains tannin, which gives the dark color to the 
 tea, and hinders the digestion. Neither tea nor coffee pos- 
 sesses any nourishing properties, except for the sugar and 
 cream that are taken with them. 
 
 17. THE HYGIENE OE DIGESTION — ALCOHOLIC DEINKS 
 I. IS ALCOHOL A FOOD? 
 
 ExPEEiMBNTS have recently been made by Professor 
 Atwatcr, of the government Department of Agriculture, 
 in which new proof of the oxidatidn of alcohol in the 
 body was collected. This has opened again the old ques- 
 tion as to whether, because of its oxidation in the body, 
 alcohol may be classified as a food. 
 
 We know that foods yield their energy by oxidation, 
 either after having been built up into living protoplasm 
 or after having been absorbed by the living protoplasm 
 and taken into the cells, though the food is not necessarily 
 
NUTRITION 111 
 
 built up into living protoplasm befcM-e the oxidation can 
 take place. 
 
 When it was found out, a good many years ago, that 
 alcohol is nearly all oxidized in the body, the question was 
 at once asked, " Is not alcohol then a food? " 
 
 Investigations were made, and the question was debated 
 with the result that alcohol continued to be classified with 
 the poisons, and not with the foods. 
 
 The question has been opened several times during the 
 last fifty years, but always with the same result. Sci- 
 entific men, generally, continue to classify alcohol as a 
 poison, and not as a food. 
 
 Morphine is oxidized in the body, and yields its energy 
 to the body, yet every one recognizes morphine as a dan- 
 gerous poison, though it is often given by physicians with 
 benefit in cases of illness. 
 
 So we see that a substance cannot safely be used as a 
 food simply because it is oxidized in the body. 
 
 A food is a substance whose nature it is, when absorbed 
 into the blood, to nourish the body without injuring it. 
 
 When we say that beef is a food, everybody under- 
 stands that we mean beef that has been cared for in the 
 usual way. If lean meat is exposed to a warm atmos- 
 phere for a number of days, a change takes place, caused 
 by the growth, within the meat, of millions of bacteria. 
 The bacteria themselves would not hurt one if they were 
 killed by cooking, but some of the waste matter (pto- 
 maines) thrown out by the bacteria would not be made 
 harmless by cooking, and might seriously poison any one 
 eating the meat. This process of decojnposition of meat is 
 a fermentation, or putrefaction, and the bacteria are called 
 organized or living ferments. 
 
 In a similar way sugar, in a dilute solution in water, if 
 
112 PHYSIOLOGY 
 
 exposed to a warm atmosphere, will undergo a fermenta- 
 tion, caused by the growth, within the solution, of millions 
 of yeast plants, which are organized or living ferments. 
 The yeast plants themselves would not hurt one, but 
 some of the waste matter thrown out by the plant would 
 not be made harmless by heating, and if kept from pass- 
 ing oft" by evaporation might seriously poison any one 
 drinking the solution. 
 
 It is the nature of meat and sugar, when absorbed into 
 the blood, to nourish the body without injuring it ; but if 
 ptomaines are formed in the meat, or if alcohol is formed 
 in the sugar solution, the previously wholesome foods be- 
 come poisonous, owing to the presence of the ptomaines 
 or alcohol. 
 
 When we use the word poison, we are likely to think 
 of a substance, such as strychnine or arsenic, that causes 
 or may cause death in a very short time. But there ai-e 
 many poisons that work very slowly, sometimes requiring 
 many years to cause death or a serious disabling of the 
 system. Painters are sometimes affected with lead poison- 
 ing, due to small quantities of lead absorbed day by day 
 for years. If a man were to take a considerable quantity 
 of the poison at once, it might cause death in a few hours 
 or days. Arsenic may be taken in very small doses day 
 after day for many years without causing death, but it is 
 no less a poison because it does its damage slowly. 
 
 When alcohol is taken in small quantities, it is oxidized 
 in the system, and gives up its heat energy to the body. 
 This heat will be given off to the body, just the same as 
 heat caused by the oxidation of sugar or bread. But 
 the condition of the body, after it has oxidized alcohol, 
 is quite different from its condition after it has oxidized 
 sugar or bread. 
 
NUTRITION 113 
 
 Benzine is very easily oxidized. If it were poured upon 
 the fire of a locomotive, it would make a furious blaze, 
 which would make the water in the boiler heat rapidl}-, 
 and that, in turn, make the wheels' turn more rapidly. 
 But the benzine would burn so rapidly as almost to make 
 an explosion, and a very large part of the heat caused by 
 the oxidation would be lost. The locomotive needs a 
 slow-burning fuel, whose heat can all be utilized. So the 
 body needs such slow-oxidizing substances as sugar, bread, 
 starch, and fat, rather than such a rapidly burning sub- 
 stance as alcohol. The energy of the alcohol is rapidly 
 expended, because the alcohol causes the blood to come to 
 the surface of the body, and the blood cools so rapidly 
 that more heat energy is lost from the body than that 
 contained in the alcohol, thus leaving the temperature of 
 the body lower than it was before the alcohol was taken. 
 
 Let us now listen to some of the leading medical men 
 as to whether alcohol may be considered a food. 
 
 "Although the relation, just alluded to, between the 
 burning of alcohol and the burning of the nutritious sub- 
 stances in the animal organism, has not been fully ex- 
 plained physiologically, this much i^ true, that alcohol, 
 taken however moderately, is not to be classed among the 
 nutritious substances." ^ 
 
 Dr. McConachie, of Baltimore, says : " Alcohol exerts 
 a pernicious influence on the development and function of 
 the muscular and nervous systems, the special senses and 
 mental activity of those who use it. This is not the role 
 played by a true food." 
 
 Dr. A. ForeP says: "Alcohol, or ethyl-alcohol, is a 
 
 1 Adolph Fick, Late Professor of Physiology, University of Wurzburg, 
 Germany. 
 
 2 Professor of Nervous Diseases in Zurich, Switzerland. 
 
 ball's phis. — 8 
 
114 PHYSIOLOGY 
 
 poisonous matter, both for the human and animal organ- 
 ism ; its venomousness increases with the amount and 
 frequency of the doses. But even when partaken of in 
 the most temperate way, it plainly interferes with the 
 functions of the various organs ; it cannot be regarded as 
 being either nourishing or strengtheijing ; and therefore 
 it is of no use whatever in a normal diet, and cannot be 
 counted as a factor of the same." 
 
 "A physicist could experiment with gunpowder and 
 prove that it is easily oxidized and gives rise to a large 
 amount of heat and energy. Prom this it might be 
 argued that gunpowder is a most useful kind of fuel for 
 cooking-stoves. Such a conclusion would be hardly less 
 logical than the conclusions that have been drawn from 
 these experiments with alcohol, and which regard it as a 
 useful food for the body. 
 
 " Gunpowder is a more unsafe fuel because of its sec- 
 ondary effects, and in the same way the food value of 
 alcohol cannot be determined by its power of being oxi- 
 dized, but must include the consideration of its secondary 
 effects as well."^ 
 
 " In order to be a food it is not sufficient that a sub- 
 stance be decomposed (or oxidized) in the tissues. Under 
 these conditions many harmful substances would be con- 
 sidered foods. Ether is decomposed in part, chloroform 
 is partially destroyed. But do we consider these sub- 
 stances foods ? Certainly not. Other things than oxida- 
 tion are necessary to nutrition. It is necessary that 
 the decomposition be made in a way that will not injure 
 the vitality of the cells. A part of the alcohol that is 
 destroyed on the body undergoes this decomposition in a 
 way that is injurious. Observe that whereas true foods, 
 1 Professor H. W. Conn, of Wealeyan University. 
 
NUTRITION 115 
 
 such as sugar and fat, are destroyed slowly, easily, without 
 provoking too lively a combustion, alcohol is burnt too 
 rapidly, provoking a veritable explosion. Suppose that a 
 locomotive has to run a certain number of kilometers ; in 
 order to do this it must be given food. This is the coal, 
 which it burns slowly and methodically. If in the place 
 of coal we throw naphtha on the fire, the combustion of 
 this may furnish as much heat as the coal, but it is burnt 
 instantaneously, in the form of an explosion. The heat 
 thus produced is not utilized in the machine. What 
 naphtha is for the locomotive, alcohol is to our bodies ; it 
 is an explosive but not a food."^ 
 
 When put to a practical test on a- large scale, as when 
 given to soldiers in severe army work, alcohol fails as a 
 food most conspicuously. " It has been shown over and 
 over again that those who endure the greatest fatigue and 
 exposure are the men who do not drink." 2 
 
 II. THE EFFECTS OF ALCOHOL UPON DIGESTION 
 
 Professor Kochlakoff, of St. Petersburg, has experi- 
 mented on five healthy persons, aged from twenty to 
 twenty-four years, with reference to the effects of alcohol 
 upon digestion. Ten minutes before each meal, each 
 person was given three ounces of alcoholic liquor, con- 
 taining from five to fifty per cent of alcohol, which is 
 about the proportion found in ordinary liquors. The 
 following results were obtained : — 
 
 " Under the influence of alcohol, the acidity of the gas- 
 tric juice and the quantity of hydrochloric acid, as well 
 
 1 Doctor Bienfait, of Liege. 
 
 2 William B. Rochester, Brigadier General, U.S.A. (Ketired). 
 
116 
 
 PHYSIOLOGY 
 
 as the digestive power of the gastric juice, was dimin- 
 ished. This enfeebling of the digestion is especially pro- 
 nounced in persons unaccustomed to the use of alcohol." 
 
 Professor Chittenden and his associates of Yale Uni- 
 versity have made extensive experiments upon dogs, and 
 have found that, though the presence of alcohol or an 
 alcoholic beverage in the stomach causes a greater amount 
 of gastric juice to be secreted, still the presence of alcohol 
 in the stomach retarded digestion. 
 
 The results which Professor Chittenden gives as 
 "strictly comparable," because "they were carried out 
 in succession on the same day," are as follows : — 
 
 Number of Experiment. 
 
 1^ lb. meat with water. 
 
 1*0 lb. meat with dilute alcohol. 
 
 XVII a 9; 15 A.M. 
 
 Digested in 3 hours. 
 
 
 Xyil /3 3; 00 P.M. 
 
 
 Digested in 3:15 hours. 
 
 Xyill a 8 : 30 A.M. 
 XVTII j8 2 : 10 P.M. 
 
 Digested in 2 : 30 hours. 
 
 Digested in 8 : GO hours. 
 
 XIX a 9:00 a.m. 
 
 Digested in 2 : 80 hours. 
 
 
 XIX j8 2 :30 p.m. 
 
 
 Digested in 3 : 00 hours. 
 
 XX a 9:15 a.m. 
 
 
 Digested in 2 : 45 hours. 
 
 XX ^2:80 P.M. 
 
 Digested in 2 : 15 hours. 
 
 
 VI a 9:15 a.m. 
 
 
 Digested in 3 : 45 hours. 
 
 VI ^1:00 P.M. 
 
 Digested in 3 : 15 hours. 
 
 
 Average . 
 
 2: 42 hours. 
 
 3 : 09 hours. 
 
 From this table of results that may be compared, we 
 see that with alcohol present in the stomach the digestion 
 was retarded twenty-seven minutes in the average result.^ 
 
 Nothing could be further removed from the truth than 
 
 I American Journal of Physiology, Vol. I, 202-203. 
 
NUTRITION 117 
 
 the popular notion that alcohol, at least in the form of 
 ccitain wines, is helpful to digestion. Roberts showed, 
 years ago, that alcohol, even in small doses, diminished 
 the activity of the stomach in the digestion of proteids. 
 Gluzinski showed, ten years ago, that alcohol causes an 
 arrest in the secretion of pepsin, and also in its action 
 upon food. Wolff showed that the habitual use of alcohol 
 produces disorder of the stomach tq, such a degree as to 
 render it incapable of responding to the normal excitation 
 of the food. Hugounence found that all wines, without 
 exception, prevent the action of pepsin upon proteids. 
 The most harmful are those which contain large quan- 
 tities of aJcohol, cream of tartar, or coloring matter. 
 Wines often contain coloring matters which at once com- 
 pletely arrest digestion, such as methylin blue and 
 fuchsin.i 
 
 Blumenau says, " On the whole, alcohol manifests a 
 decidedly unfavorable influence on the course of normal 
 digestion even when taken in small quantities, and injures 
 the normal digestive functions."* 
 
 REVIEW OF THE HYGIENE OF DIGESTIO-V 
 
 1. Cereals, vegetables, and fruit, with eggs and the dairy products, 
 make a complete and perfect diet, though meat in moderate quantities 
 may be added with advantage. 
 
 2. Meat contains, besides proteids and fats, which may be fur- 
 nished by a vegetable and dairy diet, some substance which seems to 
 stimulate men to higher endeavors. For this reason a moderate 
 amount of meat is desirable. 
 
 3. If meat is eaten in too large quantities it makes people nervous 
 and irritable, and more likely to suffer from neuralgia, rheumatism, 
 or gout. 
 
 1 J. H. Kellogg, M.D. 2 Q. F. Mather, M.D. 
 
118 PHYSIOLOGY 
 
 4. One may be intemperate in eating. One should eat only as 
 much as is needed for nourishment, and e^t at regular hours only. 
 A very good rule to follow is to eat slowly and to stop eating as soon 
 as one is satisfied. 
 
 5. Eat to live, but do not live to eat. 
 
 6. Pure water is nature's drink for plants and all animals, includ- 
 ing man. 
 
 7. In the warm weather of spring and summer one may drink 
 freely of such refreshing drinks aa lemonade and other fruit-acid 
 drinks. 
 
 8. Nourishing drinks, such as milk, cOooa, chocolate, and the 
 cereal coffees, are liquid foods, and should be taken only at meal 
 times. 
 
 9. Stimulating drinks, such as tea and coffee, are injurious to chil- 
 dren and young people, and if taken in more than moderate quantities, 
 are injurious to grown up people. There is much intemperance in 
 the use of tea and coffee. 
 
 10. Some people have claimed that alcohol is a food ; but the lead- 
 ing scientists do not say that it is a food. 
 
 11. Alcohol appears to stimulate at first, but it really lessens the 
 brain control, the self-restraint, and the wiU power, besides dulling 
 the senses and the sensibilities. Thus Alcohol is a true narcotic even 
 in small doses. 
 
 12. Scientists classify alcohol as a narcotic poison. It may take 
 years for it to seem to injure the system. The only perfectly safe way 
 to do is to abstain from alcoholic drinks altogether. 
 
 18. DOMESTIC ECONOMY 
 
 Before we can decide what to buy for our tables, we 
 must decide how much money we have to spend. In 
 mechanical lines of work men earn from fl.50 to f J: or 
 i5 a day, but in the cases where the higher wages are 
 received there is usually a time in the year when work 
 stops, so that an average pay would be about $2 a day 
 throughout the year, or about $50 a month. Men in mer- 
 
NUTRITION 119 
 
 cantile or professional lines receive salaries varying from 
 $600 to 18000 or |10,000 but a largfe proportion of men 
 in these lines of work receive about fl200 per year, so we 
 will consider 1100 a month a fair income. 
 
 What are the items of expense for which every one 
 must allow? Rent, clothes, food, and fuel one thinks of 
 at once, but there are qther equally important items to 
 consider, such as insurance, savings, benevolence, house 
 furnishings, and incidentals, which ipcludes books, school 
 expenses, and recreations. 
 
 Let us suppose these families to consist of three grown 
 people and two children, or two grown people and four 
 children, or four grown people. What proportion of this 
 money shall be given to each item of expense '? 
 
 Do you think a man can afford to give one fifth of his 
 income for a house in which to live ? He certainly can- 
 not afford to pay any more than that ; aud right here is 
 the mistake most often made — the mistake of allowing 
 too much for rent ; because increasing the size of the 
 house increases the amount necessary for helj), for fuel, 
 for lighting, and for furnishing, and at once places one in 
 the predicament of living beyond his means. Having 
 then allowed what you think best for this item, it will be 
 well to consider the item of food which must necessarily 
 be a heavy expense, and will consume not far from a 
 fourth of the income in the cases given. Must a man 
 insure his life and must he save for the future ? Cer- 
 tainly, he must provide for his family in case of his death, 
 and for himself and family in case he lives beyond his 
 working days. However small the income, this last item 
 should receive something, if possible, and the best way to 
 provide for this is to decide first how much must be saved, 
 and then apportion the rest among thd necessary expenses. 
 
120 PHYSIOLOGy 
 
 The car fares, daily papers, magazihes, school expenses, 
 books, and recreations must come under the incidental 
 account ; something must be allowed for replenishing the 
 household furnishings, and there must bo a fund from 
 which we can draw to help others, to pay our obligations 
 to church and society. 
 
 PROBLEMS 
 
 1. Let each pupil make out a budget of expenses on a 
 basis of f 100 a month or til200 per year. Here are some 
 of the questions which must arise for solution : Taking 
 such a family as that described above, — («) How much 
 per month shall I pay for rent? (b) How much per 
 month for kitchen and dining room expenses? (c) How 
 much for fuel and lighting ? (d^ How much for cloth- 
 ing? (e) How much for books, periodicals, and educa- 
 tion ? (f) How much for works of charity ? (^) How 
 much for the church? (A) How much for insurance? 
 (i) How much to be put into the savings bank ? 
 
 2. How much would your savings account amount to 
 in thirty years at three per cent simple interest ? 
 
 3. If each $1000 were withdrawn from the savings 
 bank as soon as so much had accumulated, and put at six 
 per cent interest, to how much would the total savings of 
 thirty years amount ? 
 
 4. If you were unable to work after the thirty years 
 were passed, what would your annual income be at six 
 per cent on savings, and three per cent dividends on 
 insurance ? 
 
 5. Make out a budget of expenses for a family of three 
 to come within the limits of income. If the interest and 
 dividends are insufficient, what will you do ? 
 
NUTRITION 121 
 
 19. DOMESTIC ECONOMY (continued) 
 
 Having disposed so easily of |100 a month, let us turn 
 to half that sum, which is the average workingman's 
 income, and see how much can be done with that. The 
 family is the same in size, the members of the family are 
 just as hungry, and indeed the father who works with his 
 hands needs more food than does the one who works with 
 his head. 
 
 We have decided that the first item to be provided for 
 is how much for savings ? That should be not less than 
 one fifth of the earnings and as much more as the health 
 and self-denial of the family will permit. Then he must 
 carry flOOO insurance for the benefit of his family. He 
 will then have not more than $38 to be divided among 
 the other items. As this family cannot have so much 
 money as the one on $100 per month to spend for food, 
 and must at the same time have as much if not more 
 nourishment, the question is reduced to one of food 
 values — from what foods can the most energy and nour- 
 ishment be obtained for the least m^oney. 
 
 Let us see if a family of five persons can live upon flO 
 a month for food and still be well nourished. For how 
 much can this family be warmly and comfortably clad ? 
 In the selection of clothing on this salary, attention must 
 be given to good wearing qualities and colors that will 
 not fade and look shabby in a short time. Moreover, if 
 the material has good wear in it, when it can no longer 
 be used for the one who first owned it, it will make a 
 warm garment for a smaller member. The ability of the 
 mother to do her sewing in a neat manner, the careful 
 saving of buttons to serve upon one garment after having 
 first served upon another; the careful cutting over of 
 
122 PHYSIOLOGY 
 
 garments for smaller members, in brief, the prevention of 
 waste will make the difference here between comfort and 
 discomfort, if but $10 are allowed each month for clothes. 
 
 Now let me ask how much do you think you can spare 
 for cigars and tobacco and for alcoholic drinks? You 
 have already laid out all of your money in necessary 
 things ; from which account will you cut off to allow 
 yourselves the indulgence of this appetite which gives you 
 nothing in return ? For the man with $100 a month let 
 us allow three cigars a day at five cents each or one a day 
 at fifteen cents, which is as little as most men who use 
 tobacco indulge in, and we have $4.50 a month for to- 
 bacco. If added to that ten or twenty cents a day be 
 taken off for alcoholic drinks, we must take off from $3 
 to $6 more. Shall we reduce our rent $4.50 a month and 
 our food from $3 to $6, or must we wear less comfortable 
 clothing ? If we do not take it from these items, it will 
 reduce our savings to an alarming extent. Besides, if 
 the father of the family takes from §4.50 to $7 a month 
 for the gratification of his particular taste, has not the 
 family at large a right to an equal atnount ? If they are 
 allowed another $4.60 or $7 for candy, nuts, soda water, 
 ice cream, and so forth, to be eaten between meals, we 
 must either give up all idea of saving for the future, or 
 we must cut our living expenses down another notch. 
 When we have but $50 a month and have stretched every 
 dollar to its utmost, where shall we cut off ten cents a 
 day for beer and five cents a day for tobacco, neither of 
 which will add anything to the general comfort, but all of 
 which will take from the general supply ? 
 
 From an economic standpoint alone, then, we are forced 
 to the conclusion that the use of tobacco or alcoholic 
 drinks by one or two members of a family is a most 
 
NUTRITION 123 
 
 foolish and wasteful proceeding. Furthermore, it works 
 a very grave injustice upon the other members of the 
 family. 
 
 PROBLEMS 
 
 1. Make out an annual budget on the basis of -150 per 
 month. 
 
 2. How much can you save annually ? 
 
 3. To how much will the savings amount in thirty 
 years ? 
 
 4. What will the income be after the thirty years are 
 ended and all money earning stops ? 
 
 5. How much would a man pay out for tobacco in 
 thirty years at fifteen cents per day ? 
 
 6. How much would a man pay out for drinks in thirty 
 years at fifteen cents per day ? 
 
 7. Knowing that drinkers are almost universally smok- 
 ers, how much would the man in problem 6 spend in 
 thirty years for drink and tobacco at thirty cents per day ? 
 
 8. To how much would these expenditures amount (in 
 5, 6, and 7) if each accumulated $1000 were put at interest 
 at six per cent and left to accumulate until the end of 
 the thirty "year period ? 
 
 20. DOMESTIC ECONOMY 
 
 TiiiETY dollars a month will provid*e nourishing, attrac- 
 tive food, with some delicacies, for a family of five persons 
 whose income is a hundred dollars a jnonth. 
 
 Fifteen dollars a month will provide nourishing, attrac- 
 tive food for a family of five persons whose income is fifty 
 dollars a month. 
 
 Food should be chosen with reference to its nourish- 
 ment, digestibility, cost, and variety. 
 
124 PIITSTOLOGY 
 
 Meat is the most expensive article of diet, and is usually 
 eaten too freely. 
 
 Soups are inexpensive, and with the addition of vege- 
 tables or cereals can be made very nourishing. 
 
 A variety of vegetables is advisable. 
 
 Corn, as sweet corn, hominy, corn meal (which latter 
 can be used in muf&ns, brown bread, pancakes, mush, 
 puddings, and so forth), is a cheap and nourishing food. 
 
 Fried foods should form a very small part of one's diet. 
 
 The secret of good living at low rates is to buy food 
 which is nourishing and in form easy to digest ; to buy 
 each thing in its season, and to make good use of what is 
 left over. 
 
 I. TYPICAL MENUS 
 
 Menu on $30.00 per month basis. 
 
 One of the first things to be determined in arranging a 
 menu which must come within a certain monthly limit is 
 to apportion the weekly allowance ($17.00 on above basis) 
 and then determine how much of the weekly allowance 
 must be expended for such general supplies as butter, 
 flour, milk, sugar, potatoes, lard, coffee, fuel, and so forth. 
 On a $7.00 per week basis one must allow about $3.00 
 per week for these general supplies, something as follows : 
 butter, $.50; flour, 1.25; milk, $1.00, sugar, $.25 ; pota- 
 toes, $.15; lard, $.05; coffee, $.10; fuel, $.60; inci- 
 dentals, $.10. 
 
 TYPICAL MENU FOR ONE DAY 
 
 Breakfast — Oatmeal ($.02), sugar and cream, waffles, 
 maple sirup, cereal coffee. 
 Luncheon — Omelet ($.10), bread and butter, milk. 
 
NUTRITION 125 
 
 Dinner — Pork and beans (f.l2), tomatoes (1.05), 
 baked potatoes, brown bread and butter ($.05), baked 
 apples and cream (•i5.05). 
 
 On a $50.00 per month income, not more than .fl5.00 
 per month should be allowed for board. That brings one 
 down to f3.50 per week for a family of five. Of this 
 about f2.00 per week will be expended for such general 
 supplies as milk, $.50; flour, '^.35; sugar, #. 25 ; butter, 
 $.35; lard, $.10; cereal coffee, $.10; potatoes, $.25 ; sirup, 
 $.10 ; incidentals, $.10. 
 
 TYPICAL MENU FOR ORE BAY 
 
 Breakfast — Bacon ($.05), potatoes, bread and butter, 
 coffee. 
 
 Dinner — Beefsteak (round, $.12), potatoes, bread and 
 butter. 
 
 Supper- — Cream of onion soup ($.01), bread and butter. 
 
 n. PROBLEMS 
 
 1. Get a list of market prices for various staple articles, 
 such as those mentioned under general supplies, also vari- 
 ous vegetables, meats, cereal foods, and so forth. 
 
 2. Find out from home or from the teacher the amount 
 of the various supplies needed for a nieal for five persons. 
 
 3. Find the most economical way to choose the various 
 cuts of meat. For example, some cuts, if large enough, 
 will be sufficient for several days if used in made-up 
 dishes like stews and meat pies for the last one or two 
 meals. 
 
 4. Make out a complete menu for a week on the basis 
 of $7.00. 
 
 5. Make out a complete menu for a week on the basis 
 of $3.50. 
 
CHAPTER VI. — CIRCULATION — HOW THE 
 NOURISHMENT IS DISTRIBUTED 
 
 1. THE NEED FOR A CIRCULATORY SYSTEM 
 
 Nearly all of our study of physiology up to the 
 present time has been devoted to the study of foods and 
 their preparation, and to the process of the mastication 
 and digestion of foods. 
 
 After the food is digested, it is absorbed into the system 
 from the alimentary canal and forms a part of the blood 
 and lymph of the body. This blood and lymph is tissue 
 and cell food. Every cell of the body requires food in 
 order to enable it to do its work, and it requires a particu- 
 lar kind of food. The cells of the body are working for 
 their board and room, that is, for their nourishment and 
 protection. Their protection is accomplished by their 
 being colonized together in the body ; their nourishment 
 is provided in a common stock of nutriment carried by 
 the blood. The cells are constantly drawing their supply 
 from this common stock, and the blood is just as con- 
 stantly being replenished by absorption from the digested 
 foods of the alimentary canal. 
 
 The problems which we have to selve in this chapter 
 are, first, what is the composition of the blood, and 
 second, how is the blood distributed to the different cells 
 and tissues. 
 
 Let us now consider the general character of the dis- 
 tributing system. Most of you are familiar with the 
 
 126 
 
CIRCULATION 127 
 
 method which cities and many towns use in distributing 
 water to the different houses. You know that large 
 mains, as they are called, or large tubes run from a 
 central pumping station along the main thoroughfares of 
 a city, giving off from time to time branches which pass 
 along side streets and supply portions of the city not 
 reached by the main channel ; finally, every house has its 
 water pipes, and, after entering the house, the pipes sub- 
 divide, each branch finally going to a faucet or other 
 terminal fixture. When the faucet is turned, the water 
 will flow with more or less force, and may be utilized for 
 various household purposes, after which it is carried off 
 first in small pipes that converge to one of considerable 
 size, which leaves the building and passes to the street, 
 where it empties into a still larger one. 
 
 In a similar way the drainage or sewerage of a whole 
 city is collected in pipes of ever increasing size, and finally 
 carried away from the city in large mains, to be emptied 
 into some lake or river, and finally to the sea. From the 
 sea the water is vaporized, carried in the form of clouds 
 by the wind out over the land, where it falls as rain, and 
 may be again used by a city, perhaps by the same city that 
 used it at first, though it is not likely that any consider- 
 able amount of the water so purified ever does actually 
 come back to the same city which once used it; and for 
 this reason the water sewerage of a pity cannot be called 
 a circulatory system. 
 
 In the animal body we have a striking analogy to a 
 great city : first, in the need of individual cells for liquid 
 and solid; second, in the actual distribution of this 
 through a system of tubes ; third, in the collection of 
 refuse matter or sewage of the systeih into another system 
 of tubes ; fourth, the purification of the sewage. If the 
 
128 PHYSIOLOGY 
 
 purified sewage of a city were returned and pumped 
 through the same channels for the water supply, the 
 analogy would be perfect, because in the animal body the 
 purified blood passes into the pumpilig station and is at 
 once sent out again through the system of supply tubes. 
 This fact of the blood making the circulation of the body 
 repeatedly, at one time carrying fresh liquid and food, 
 and another time carrying refuse, has caused the whole 
 system of tubes to be called a circulator y system. 
 
 As the stream of pure blood in its blood vessel, bring- 
 ing both water and nourishment, enters a tissue, it at once 
 divides into minute tubes called ca^jillaries, which dis- 
 tribute the blood to each part of the tissues. The blood 
 does not actually empty out into the tissues, as is the case 
 in a water tube that empties out from a faucet into a wash 
 bowl, but the wall of the tube being thinner than tissue 
 paper, there is a ready exchange between the pure blood 
 within the capillary and the impure plasma outside, so that 
 by the time the capillary has' passed through the tissue, it 
 has given to the tissue much that was pure and has taken 
 up from the tissue much that was impure ; joining with 
 many other capillaries, the stream passes out of the tissue 
 charged with the impurities of tissue waste and tissue 
 oxidation. 
 
 2. THE BLOOD 
 
 From what we have learned, it must be clear that the 
 blood is a very complex liquid, because it contains food for 
 every tissue and cell of the body. Some tissues require 
 proteid food, some fats and carbohydrates, while others 
 require mineral food. The blood must also contain all 
 the waste materials. The blood carries not only liquid 
 
CIRCULATION 
 
 129 
 
 food, but gaseous food, the gas being dissolved in the 
 liquid, and not being in the form of bubbles. 
 
 You have all seen blood flowing from a cut or from a 
 bleeding nose, and know that it is red. Not all animals 
 have red blood ; the oyster and the lobster have white 
 blood; the common earthworm or angleworm has red blood, 
 and all animals that have a backbone have red blood. 
 There is a very great difference between the blood of 
 the angleworm, however, and the blood of a frog. In the 
 angleworm, the red color of the blood is due to a red 
 pigment which is dissolved in the blood, as the red pig- 
 ment of raspberries or currants is dissolved in a sirup, 
 giving the sirup its red color. 
 
 But the blood of vertebrates owes its red color to 
 innumerable red bodies floating in the blood. These red 
 bodies are called corpus- 
 cles. A thin film of blood 
 spread upon a glass and 
 looked at under a high 
 power microscope would 
 look like Figure 28. In 
 studying this figure you 
 will notice first that there 
 are two kinds of bodies 
 floating in the liquid, one 
 a smooth, discoidal body, 
 and the other a granular, 
 spherical body. The 
 smaller discoidal bodies 
 are the ones which contain the red pigment, and because 
 of their color they are called red corpuscles. The granu- 
 lar, spherical corpuscles are perfect cells composed of 
 protoplasm, and containing one or more nuclei. This 
 
 nALI-'S PHVS. — 9 
 
 Fig. 28. — Blood corpuscles as they appear 
 under the microscope: B, C, 1), E, red 
 corpuscles seen in different positions; 
 F, G, white corpuscles. Notice that at 
 D, D, the refl corpuscles have gathered 
 in rouleaux like coins when shaken 
 together. 
 
130 PHYSIOLOGY 
 
 form of protoplasm generally has the power of contract- 
 ing, and so these cells have the power of changing shape, 
 like the amoeba of which we studied under General Physi- 
 ology ; and because of this power to change their shape 
 they can creep through little pores or openings in the 
 wall of the capillary, and when once free from the capil- 
 lary they can creep through the pores between the cells 
 of the tissue. These creeping, granular corpuscles are 
 called white blood corpuscles. 
 
 The red corpuscles are derived from nucleated cells, 
 and may themselves be called modified cells, but they 
 have not the power to change their shape, and all that 
 they do is done passively and not actively ; that is, they 
 are acted upon rather than active. 
 
 Blood, then, is composed of a nearly colorless fluid 
 called plasma, in which two kinds of cells are floating, 
 the white cells and the red cells, qi-, as they are more 
 frequently called, the white corpuscles and the red corpus- 
 cles. The fluid part of the blood, the plasma, carries the 
 liquid nutriment from the alimentary canal to the tissues. 
 Prom this we should expect the plasma to contain pro- 
 teids, carbohydrates, and fats, and so it does. The 
 carbohydrate is the grape sugar, or dextrose, absorbed 
 from the alimentary canal ; the fat is in the form of 
 minute globules, while the proteid is in the form of 
 albumen, similar to egg albumen, but much diluted with 
 water. Besides these foods already named, there are water 
 and mineral substances in solution. Ilie minerals are, for 
 the most part, those which are utilized in the building up 
 of tissues. The plasma also contains many waste sub- 
 stances, which are constantly being added to by the 
 tissues and just as constantly being carried away by the 
 excretory organs. 
 
CIRCULATION 131 
 
 In a similar way the foodstuffs are being added to the 
 plasma by absorption from the alimentary canal, and con- 
 stantly being taken away from the plasma by the tissues, 
 so that there are in constant progress two additions to the 
 plasma and two subtractions from it ; still, the wonderful 
 adaptation of the system and the delicate control by the 
 nervous system result in keeping the plasma in nearly the 
 same condition, varying more in the relative amount of 
 water than in any other constituent. 
 
 The work of the red blood corpuscles is to carry oxygen 
 from the lungs to the tissues ; the work of the white 
 blood corpuscles will be described later. 
 
 3. HOW THE BODY IS PROTECTED AGAINST EXCES- 
 SIVE BLEEDING 
 
 Evert schoolboy knows that if he cuts his finger deeply 
 the blood will come streaming out ; he knows, too, that 
 the blood will flow only a short time and then stop ; he 
 knows, too, that if the blood is allowed to collect upon the 
 finger, not being rubbed off or rinsed off with water, that 
 in two or three minutes it will form into a jellylike mass 
 upon the finger, and if this jellylike niass is brushed away 
 after the bleeding stops, he will find that the c\it is filled 
 with blood which seems to be in the same condition as 
 that which he brushed away. 
 
 This is nature's method of stopping the bleeding. The 
 jellylike mass, which forms whenever the blood is exposed 
 to the air after being shed, is called a co-ay' u-luvi, and the 
 process of its formation is called coagulation. 
 
 You will remember that in describing milk, when we 
 were studying about foods, the milk separated into small, 
 flakelike eoagula on the addition of acid. Each little 
 
132 PHYSIOLOGY 
 
 mass of the milk would be called a coagulum. You know 
 that if milk is exposed to the warm air for a few hours 
 on a summer's day it will turn into a jellylike mass simi- 
 lar in consistency to the coagulum of the blood. The 
 process which takes place in the milk is similar to the 
 process which takes place in the blood during coagulation. 
 
 Sweet milk contains a proteid called caseinogen. When 
 the milk is exposed to the air, a ferment which floats in 
 the air gets into it and causes a fermentation of the milk 
 sugar, which results in the formatioji of milk acid, and 
 that causes the caseinogen to be separated out in the form 
 of casein. 
 
 The blood contains several liquid proteids similar to 
 the white of egg. One of these is called fibrinogen. 
 When the blood is shed, and comes into contact with the 
 air, or any foreign substance, a ferment which is always in 
 the blood, but which does not act when the blood is cir- 
 culating within the vessels, begins to act upon the fibrino- 
 gen, causing it to separate out into stringy fibers. These 
 fibers form a network in whose meshes the red blood 
 corpuscles and the fluid part of the blood are caught. 
 
 In some animals the blood coagulates very quickly, and 
 in some animals very slowly. The blood of insects and 
 small birds coagulates almost instantly ; human blood 
 coagulates in two to flve minutes or more, according to 
 various circumstances. The blood of horses coagulates 
 in not less than five minutes. The coagulation is hastened 
 when the blood comes in contact with foreign matter of 
 any kind, and especially with air or with foreign matter at 
 a temperature considerably higher than that of the body. 
 If a deep wound is bleeding so freely as to endanger life 
 from loss of blood, the coagulation can be hastened by 
 binding over the wound absorbent cotton or linen. 
 
CIRCULATION 133 
 
 If a boy were to lose a tablespoonful of blood he might 
 be quite frightened, thinking that he was bleeding to 
 death, but it has been found out by experiment that about 
 one thirteenth of the weight of the body is blood, so that 
 any person weighing ninety-one pounds would have nearly 
 a gallon of blood, and at least one third of this or more 
 than a quart could be lost without in any way endanger- 
 ing the life of the person. 
 
 If a large blood vessel were cut, the blood might flow 
 too rapidly to be stopped by coagulation alone, so that 
 unless some prompt measures be taken a person might bleed 
 to death in a few minutes. Just what to do in such an 
 emergency will be. described later, after we have described 
 the blood vessels. 
 
 4. THE ORGANS WHICH CAUSE THE BLOOD TO CIR- 
 CULATE 
 
 THE HEART 
 
 Many of you have visited the village or city water- 
 works, and have seen the great engine pumping the water 
 through the system of tubes described in a previous lesson. 
 When the pump stops, the water ceases to flow. In a 
 siinilar way the blood is forced through the system of 
 blood vessels by a pumping organ, the heart. When 
 the heart pumps rapidly the blood flows rapidly, and when 
 the heart pumps slowly the blood flows slowly. If this 
 central pump were to stop its work, the blood would stop 
 flowing. The cells all over the body would be deprived 
 of their proper nourishment and oxygen, and would have 
 to stop working. So we see how important an organ the 
 heart is. 
 
134 
 
 PHYSIOLOGY 
 
 Figure 29 gives the outside view of the heart ; this 
 shows the heart as it would look if we could look into 
 
 the chest of another, and see 
 the heart lying there so that 
 what is on the right side in 
 the picture (Fig. 29) would 
 represent the left side in the 
 body. 
 
 Notice that the upper left- 
 hand portion of the heart is 
 a little earlike appendage ; 
 this is called the left auricle 
 (left ear). There is a much 
 larger chamber at the upper 
 right-hand part of the heart 
 which is called the right 
 auricle. 
 
 These, auricles are filling 
 chambers for the heart, which 
 hold the blood while the 
 pumping chambers of the 
 
 FiG.29.-The heart and large Wood ^eart are forcing the blood 
 vessels, in front. 1, right ventricle; into the arteries. These 
 
 2, left ventricle ; 3, pulmonary ar- ■ i i j. 
 
 t;ry,cutshort;4,4'%",aorta, or pumping chambers are two 
 chief artery ; 5, 6, parts of the right in number. They make up 
 
 and left auricle ; 7, 7, veins uniting , , ■ i i i- , i i j 
 
 to form the superior (upper) vena t^^ main body of the heart, 
 
 cava ; 8, inferior vena cava ; 9, vein One of the chambers is di- 
 from liver; +, arteries nourishing , , ,, , „ . , 
 
 the heart. rectly under the left auricle, 
 
 and is called the left ventricle, 
 while the chamber under the right auricle is called the 
 right ventricle. 
 
 The general relation of these chambers of the heart 
 can best be shown by a diagram (see Fig. 30). 
 
CIRCULATION 
 
 135 
 
 Notice that the blood enters the left auricle through 
 vessels from the lungs (pulmonary veins) ; that it passes 
 from the left auricle into the left ventricle through the 
 bicuspid valve ; when the left ventricle contracts and 
 forces the blood back against the bicuspid valve, the 
 valve closes, and the blood cannot get back into the auri- 
 cle, but it can pass out into the aorta, and from the aorta, 
 which is the largest artery of the body, the blood is dis- 
 tributed all over the body, 
 coming back to the heart 
 from the veins, and enter- 
 ing the right auricle. 
 Prom the right auricle it 
 can pass through the tri- 
 cuspid valve into the right 
 ventricle, and when this 
 ventricle contracts, the 
 cusps of the tricuspid 
 valve are forced together 
 and closed, while the valve 
 into the pulmonary artery 
 is forced open. 
 
 The impure blood passes 
 out to the lungs to be puri- 
 fied, and after purification 
 it returns through the pulmonary veins already referred 
 to into the left auricle. 
 
 The left side of the heart has to force the blood all over 
 the system, while the right side of the heart has only to 
 force the blood into the lungs which lie all about the 
 heart in the thorax. For this reason the left side of the 
 heart has a very heavy muscular wall, while the right 
 side of the heart has a much thinner one. 
 
 Fig. 30. — Diagram illustrating the course 
 of the blood through the heart. [Tracy.] 
 
136 PHYSIOLOGY 
 
 5. THE OKGANS WHICH CAUSE THE BLOOD TO 
 CIRCULATE (continuled') 
 
 THE AETBEIBS 
 
 The tubes which conduct the water from the pump- 
 ing system of the city to the various houses are composed 
 of either stoneware or iron. The smaller subdivisions 
 within the house which go to the different faucets are 
 metal. 
 
 The system of tubes which conduct the blood over the 
 body begins at the heart with a large, thick-walled tube, 
 a little larger than one's thumb. This tube is called the 
 aorta. 
 
 All of the tubes which carry blood away from the heart 
 are called arteries. The aorta is the main trunk of this 
 system of tubes. The accompanying plate (page 137) 
 shows the aorta passing upward from the base of the 
 heart, curving around at the base of the neck, and then 
 passing downward along the spinal column. Notice that 
 it gives off branches as it passes downward and therefore 
 becomes smaller and smaller, and divides into two main 
 branches, one passing to each leg. 
 
 The larger divisions of the aorta are those which pass 
 to the legs and arms, next in size being those which pass 
 to the kidneys (page 137). These large branches sub- 
 divide into numerous smaller branches and twigs, the 
 subdivisions passing outward in every direction, and 
 carrying the blood stream to every portion of every tissue 
 in the body. 
 
 When the blood reaches the tissues which it is to 
 nourish, the artery subdivides into branches not larger 
 than a needle. These little arteries are called arterioles. 
 
138 
 
 PHYSIOLOGY 
 
 The arterioles finally subdivide into a network of minute 
 hairlike branches called capillaries. Many of the capil- 
 laries are so fine that there is room for only one corpuscle 
 to pass along at a time. These capillaries have walls so 
 thin that the blood plasma can ooze through as the blood 
 filters through the tissues. 
 
 Several venules coming together form a vein, and one 
 vein emptying into another vi'ill form a large venous 
 trunk. Eefer to page 137, and notice the venous trunk 
 getting larger and larger as it passes toward the heart, 
 receiving branches from either side. The large vein 
 which passes up through the abdomen to 
 the right auricle of the heart is the inferior 
 vena cava; the one which comes down from 
 the head and arms, enlptying into the right 
 auricle, is the superior, vena cava. 
 
 It has been mentioned above that the 
 wall of the aorta is very thick and strong. 
 It is composed mostly of very dense, 
 strong, elastic fibers of connective tissue, 
 but there are some muscular fibers in the 
 outer portion of the wall of the aorta, and 
 the wall is lined with a very thin mem- 
 brane, thinner than tissue paper, composed 
 of little platelike cells lying side by side, 
 as shown in Figure 31. 
 Fig. 31.— Lining of The Smaller arteries have a much thinner 
 
 FschaZ.r ''"■ ^^^^' ^^^°^' ^' composed largely of mus- 
 cular tissue with only a little of the 
 elastic connective tissue ; the lining is the same as that 
 of the aorta. 
 
 As we pass to the finer twigs of the arterial system, we 
 find the muscular coat and the elastic coat becoming 
 
CIRCULATION 
 
 139 
 
 thinner and thinner ; finally in the capillaries only the 
 inner coat remains, and, as has been stated above, this 
 coat is so thin and delicate that the blood plasma can 
 ooze through it as the blood 
 is forced by the heart through 
 the capillary network. (Study 
 Figure 32.) 
 
 The walls of the veins, al- 
 though they are much thinner 
 than those of the arteries, are 
 made in the same way. That 
 is, they are made of elastic 
 connective tissue, muscular 
 tissue, and the thin inside lin- 
 ing. The veins have some- 
 thing which the arteries do 
 not have, and do not need ; 
 the veins have valves. These Fra. 32. -Capillary network show- 
 
 ing how the walls are made of thin 
 
 valves are so arranged that plate-cells. [Schaefer.] 
 they open toward the heart. 
 
 Thus they allow the blood to flow toward the heart, 
 but do not allow it to flow back. If anything presses 
 upon a vein, the blood may be hindered from continuing 
 its flow toward the heart, but it cadnot be pushed back 
 into the capillaries. 
 
 There are none of these valves in the veins of the neck 
 and face, because they are not needed there in the usual 
 positions of the body. 
 
 When the body is inverted, as when one hangs with his 
 head downward, the blood backs up or flows back into the 
 venules and capillaries of the face and neck, making the 
 skin flushed and almost purplish, if one keeps the position 
 for some time. 
 
140 
 
 PHYSIOLOGY 
 
 6. THE CIRCULATION OF 
 THE BLOOD 
 
 The blood cannot circulate 
 by any force of its own, but 
 it is forced tlirough the arterial 
 system, the capillaries, and the 
 veins by the pumping of the 
 heart. If you will refer to 
 Figure 33 you will find a dia- 
 gram of the circulation ; the 
 lighter portion represents the 
 arterial system, the darker por- 
 tion the venous system. 
 
 This diagram represents 
 what are called the greater 
 and lesser circulations. The 
 greater circulation is that 
 which supjjlies the whole body 
 with blood, beginning with 
 the aorta with its numerous 
 branches distributed through- 
 out the system, and ending 
 with the vense cavse which 
 bring the blood back to the 
 right auricle. 
 
 Notice in the diagram that 
 from the right ventricle the 
 dark stream passes upward to 
 
 Fig. 33. — Diagram of the circulation. 
 1, lieart ; 2, luugs ; 3, head and upper 
 extremities ; i, spleen ; 5, intestine ; 6, 
 kidneys ; 7, lower extremities ; 8, liver. 
 [Dalton.] 
 
CIRCULATION 141 
 
 the lungs. This stream is tlie pulmonary artery, carrying 
 impure blood from the heart to the lungs, where it is 
 oxygenated, after which it passes back to the left auricle 
 through the pulmonary veins. This portion of tlie general 
 circulation which carries the blood to and from the lungs 
 is called the lesser circulation, or the lung circulation. 
 
 Let us now follow the circulation in detail, beginning 
 with the left auricle. Turn back to Figure 30 and notice 
 that the blood flows into the left auricle from four pul- 
 monary veins ; from the left auricle it passes through the 
 bicuspid valve into the left ventricle. It passes into the 
 left ventricle because the muscular walls of the left auricle 
 contract and force it into the left ventricle. It does not 
 require much force at first, because the left ventricle is 
 empty ; all the force required is enOTigh to swell out its 
 walls. After the auricle has emptied itself into the left 
 ventricle, the ventricle begins to contract. Its contrac- 
 tion presses the blood up toward the base of the heart. 
 This forces the valve together, thus closing the opening 
 into the left auricle, so that no blood can get back that 
 way. The ventricle keeps on contracting until the pres- 
 sure against the valves into the aorta is sufficient to push 
 them open and force the blood that wijs in the left ventri- 
 cle out into the aorta. After the ventricle has emptied 
 itself into the aorta and relaxes, the valves of the aorta 
 clap together and hold the blood in the aorta while the 
 ventricle is being filled again from the auricle. The 
 contraction of the ventricle which throws the blood into 
 the aorta is called the systole. 
 
 Now turn to Figure 33 ; folloAV the blood from the left 
 auricle into the left ventricle (marked 1) and from the 
 left ventricle around the curve of the aorta. The diagram 
 shows a large branch turning upward to the head and 
 
142 PHYSIOLOGY 
 
 arms. This branch in the diagram really represents sev- 
 eral different arteries, so that the diagram is intended to 
 represent only the general features of the circulation. 
 After giving off blood for the head and arms, the aorta 
 turns downward through the thorax and abdomen, giving 
 off many small branches that run between the ribs and a 
 large one to the spleen (Fig. 38, 4), then there are large 
 branches to the stomach and intestine's (Fig- 33, 5), then 
 branches to the kidneys (Fig. 33, 6), and, finally, branches 
 to the legs (Fig. 33, T). 
 
 In all of these different organs to which the blood is 
 supplied, it filters slowly through the capillary network 
 and collects in venous branches corresponding to the 
 arterial branches. Notice that the blood from the spleen, 
 stomach, and intestines collects into a large venous trunk 
 (marked by the white arrow), and passes to the liver 
 (Fig. 33, 8). This is the portal vein. All the venous 
 blood finally collects in the right auricle, whence it passes 
 into the right ventricle (see also Fig. 30) ; the right 
 ventricle contracts at the same time that the left ventricle 
 does, and sends the blood through the pulmonary artery 
 to the lungs (Fig. 33, 2), where it is oxygenated, after 
 which it passes to the left auricle, thus completing the 
 circulation. 
 
 The blood flows very rapidly in the aorta and the large 
 arteries, but as it reaches the tissues and passes into the 
 innumerable small branches the flo\y becomes very slow, 
 thus giving a good chance for an exchange to occur between 
 the blood circulating in the capillaries, and the cells which 
 border the capillaries. As the blood collects again in 
 the venules and veins it begins to flow faster, and con- 
 tinues to increase in its rate of flow- until it reaches the 
 heart. 
 
CIRCULATION 143 
 
 6. THE CIRCULATION OF THE BLOOD (continued) 
 I. THE PULSE 
 
 If you put the tips of the fingers upon the wrist near 
 the base of the thumb, you will feel a little throbbing. 
 This throbbing is called the pulse. All the arteries throb 
 or pulsate, but the pulsation of only those larger arteries 
 which are located near the surface can be felt. If one 
 puts the tips of his fingers just in front of his ear, he can 
 feel the pulsation of an artery. A pulsation may also be 
 felt on the side of the neck. 
 
 What causes the pulse ? When the heart contracts, it 
 throws about half a tumbler full of blood into the aorta ; 
 this forces the elastic walls of the aorta to quickly stretch, 
 and it starts a wave down the arterial system, a wave 
 which follows all the branches of the arterial system clear 
 to the farthest branches of the arterioles. This wave is 
 called the pulse. 
 
 When the physician presses his fingers upon one of 
 these arteries, he can tell by the way it throbs whether 
 the heart is beating rapidly or slowly, whether it is strong 
 or feeble, and whether the smaller arteries are congested 
 or relaxed. So much depends upon the condition of the 
 heart and the circulatory system in general, that it has 
 become customary for the physician to feel the pulse as 
 one of his preliminary tests. 
 
 II. PROTECTION AGAINST BLEEDING 
 
 The reason that we do not feel the pulse at almost any 
 part of the surface of the body is because most of the 
 larger arteries are located far beneath the skin. These 
 arteries are in tlie safest portion of the system; if they 
 
144 
 
 PHYSIOLOGY 
 
 were nearer the surface they might easily become wounded 
 in some of the various injuries whiph the body suffers, 
 such as a cut with a knife, and then tlie blood would flow 
 
 so rapidly as to endanger the 
 " life of the person. Even with 
 
 this protection large arteries or 
 veins are sometimes cut. 
 
 It is very important for every 
 one to know what it is best to 
 do when that happens. If the 
 vessel is an artery, the blood will 
 come in spurts because of the 
 pulsations. To stop the bleed- 
 ing of an artery it is necessary to 
 press against the trunk of the 
 artery. This pressure must be 
 between the bleeding end of the 
 artery and tlje heart. 
 
 The best method for making 
 
 Fig. 34. — Manner of compress- this pressure is to take a hand- 
 ing an artery with a handker- ijej,ohief by its corners, make it 
 chief and stick. [Iracy.J •> ' 
 
 into a roll, arid tie a single knot 
 in the middle ; pass the handkerchief around the limb 
 with the knot above the wound, and tie the ends so that 
 the knot is not tightly drawn; put a stick through (a ruler 
 or a lead pencil might serve the purpose) and then twist 
 the handkerchief tightly enough to stop the bleeding 
 (Figure 34 represents the handkerchief so applied). 
 
 III. HOW THE BLOOD NOUEISHES THE TISSUES 
 
 When the blood reaches the tissue^ and is slowly filter- 
 ing through the fine capillaries, some very important 
 
CIKCULATION 
 
 145 
 
 things happen, in fact, the very things for wliich the 
 whole circulatory system exists. 
 
 The plasma of the blood oozes out through the fine 
 pores between the cells of the capillary wall, carrying to 
 the hungry cells which make up the tissue the food which 
 they most need. Some of the fresh plasma passes into 
 the tissue ; some of the plasma whiph was in the tissue 
 
 Fig. 35. — Showing liow white corpuscles get tlirough the walls ot the 
 capillaries. [Hall.] 
 
 before, and from which a portion of the nourishment has 
 been taken up by the cells, will pass out of the tissue 
 through the lymph vessels, and, after passing through 
 the lympli circulation, will finally pass back into the 
 blood circulation. 
 
 But tills is not all that happens while the blood is pass- 
 ing through the capillaries. Figure 35 shows under A 
 the way in whicli the blood corpuscles usually float 
 through a large capillary; under B the figure shows what 
 happens when there is something wrohg in the cells wliich 
 
146 PHYSIOLOGY 
 
 border the capillaries. The white corpuscles leave the 
 center of the stream, pass to the capillary wall, put out a 
 little arm such as shown in cells marked 2 (Fig. 85), 
 force this arm through a little opening in the capillary 
 wall, then gradually creep through the wall as shown in 
 the cells marked 3 (Fig. 35). 
 
 When once they are free and in the cells of the tissue 
 (see cells marked 4 in Figure 35), they put out little arms 
 and creep about repairing any damages which the cells 
 may have suffered. 
 
 If a sliver has been thrust into the tissue, they will 
 gather about the sliver in such great numbers as to 
 make a soft covering, thus protecting the tissue from 
 farther damage by the intruder. If microbes have got 
 in, the white corpuscles will eat up the microbes, thus 
 in most cases protecting the rest of the tissue from the 
 action of these parasites. Sometimes, however, there are 
 too many microbes or bacteria to be thus disposed of, 
 when they will accumulate in the system and cause a 
 fever or some disease. 
 
 IV. WHBRB THE BLOOD LOSES ITS OXYGEN 
 
 . We have mentioned how the blood becomes oxygenated 
 in the lungs. It leaves the lungs in a bright scarlet 
 stream ; it retains this appearance until it comes to the 
 capillaries, where it gives up its oxjgen to the hungry 
 tissues. 
 
 As soon as it loses its oxygen, it loses its bright scarlet 
 color, becoming dark purplish red, which color it retains 
 throughout its course through the ve'nous system back to 
 the heart (Fig. 36). 
 
CIRCULATION 147 
 
 7. THE LYMPH AND ITS CIRCULATION 
 
 At the end of the previous lesson we were studying the 
 changes which take place in the blood during its passage 
 through the capillaries. We found that blood plasma, 
 laden with food for the cells, passes through the pores in 
 the capillaries and oozes through tlie tissue, through the 
 spaces between the cells. 
 
 We found also that the white blood corpuscles pass out 
 
 Capillary Network 
 
 FjG. 36. — Capillary network showing change from arterial to venous blood. 
 
 through these little pores in the capillary walls. They 
 pass out in large numbers only when there is some con- 
 dition in the tissues which they can eorrect. 
 
 But they are continually on the lookout for danger, and 
 an occasional white blood corpuscle may pass through the 
 capillary at any time, so that there are always some white 
 blood corpuscles in the tissue spaces. 
 
 The plasma and white corpuscles make up what is 
 called tissue lymph. The tissue lymph soon becomes 
 changed by tlie addition of substances thrown out through 
 
148 
 
 PHYSIOLOGY 
 
 the cells of the tissue, so that tissue lymph does not retain 
 the same composition that the blood plasma had. As the 
 plasma keeps coming into the 
 tissues from the capillaries, it 
 forces the plasma on and keeps it 
 moving. After oozing through 
 the tissue into which it first passed, 
 it soon finds its way into little 
 vessels which are like veins, except 
 that they contain only lymph 
 (Fig. 37). 
 
 Once the lymph enters a vessel 
 called a lympliatic, it may be called 
 circulatory lymph ; it does not 
 again enter the tissue, but con- 
 tinues to move through lymphatics 
 toward the heart in a way quite 
 similar to that in which the venous 
 blood moves toward the heart 
 from the tissues. Small lymphat- 
 ics come together and make larger 
 ones, until finally a very large 
 lymphatic vessel passing up 
 through the abdomen and thorax 
 receives the lymph from the other 
 lymphatics, and finally pours it 
 into the venous system. 
 
 In Figure 37, notice the little 
 lymphatic glands which lie in the 
 course of the lymphatics at 2. 
 These glands are made up of a 
 fine network of fibers, in the meshes of which there are 
 innumerable little cells. As the lymph filters through 
 
 Fio. 37. — Lymphatic vessels 
 of the surface of the arm. 
 1, ducts; 2, glands. 
 
CIRCULATION 149 
 
 one of these glands, some of the white corpuscles which 
 have become old and sluggish in their movements, get 
 entangled in the network and die. 
 
 But the lymph which leaves the gland has more white 
 corpuscles than that which enters the gland, because 
 young corpuscles are being constantly formed in the 
 gland, so that a lymph gland is at the same time the 
 grave of old white corpuscles and the birthplace of young 
 white corpuscles. 
 
 Looking again at Figure 37, you will notice that the 
 larger lymphatics seem to have little joints, or nodes. 
 The nodes show where the valves are located. What is 
 the use of the valves ? The pressure of new blood plasma 
 filtering into the tissue is sufficient to keep the tissue 
 plasma moving, but it is not always sufficient to make the 
 lymph pass up through the lymphatics to the heart. These 
 valves are open toward the heart, allowing the lymph to 
 flow easily in that direction, but they close as soon as the 
 lymph is pressed back, and do not allow it to flow away 
 from the heart. 
 
 Now in the movements of the body, especially of the 
 arms and legs, the lymphatics are pressed upon by the 
 contracting muscles. This pressure forces the lymph out 
 of the lymphatics toward the heart because it cannot go in 
 the opposite direction, thus leaving the lymphatics empty 
 and ready to fill very easily from behind as soon as the 
 pressure is relieved. 
 
 From this it must be clear that muscular movements of 
 the legs, arms, and body assist the lymph circulation (it 
 may be added here that it assists also the circulation in 
 the veins), and in that way assists the nutrition of the 
 tissues. In fact, the secret of the influence of muscular 
 exercise upon the general health lies more in its action 
 hall's phys. — 10 
 
150 
 
 PHYSIOLOGY 
 
 upon the lymphatic and venous circulations than in any- 
 thing else. 
 
 An important part of the lymphatic system is that 
 
 which collects the tis- 
 / sue fluid from the in- 
 
 testine, carrying it to 
 the thoracic duct (Fig. 
 38). This portion of 
 the lymphatic system 
 differs from the rest 
 in carrying absorbed 
 foods from the intes- 
 tines to the circula- 
 tory system. 
 
 The veins of the in- 
 testine carry part of 
 t^jie food, but the lym- 
 phatics carry all of 
 the absorbed fat. This 
 fat is in the form of 
 an emulsion something 
 like cream, and makes 
 the lymphatics of the 
 intestine look white, as 
 '"•--.._ / though they were fiUed 
 
 T. i» T * 1 *^ ■ ^ . . '■ 'with milk. For this 
 
 Fig. 38. — Lacteals, thoracic duct, etc. a, in- 
 testine; 6, vena cava inferior; c, c, right reason these particular 
 
 and left subclavian veins ;d point ol open- lymphatics have been 
 ing of thoracic duct into left subclavian. •'• r """ ^^^^ 
 
 [Daiton.] called lacteals (from 
 
 the Latin lac, milk). 
 This white lymph is sufficiently different from the rest 
 of the lymph of the body to have a separate name ; it is 
 called chyle. 
 
CIRCULATION 151 
 
 8. THE CONTROL OF THE CIRCULATION 
 CONTROL OF THE HEART 
 
 Put your finger upon your pulse and count the number 
 of times it beats in a minute. Count it again and see if 
 you can make it beat faster this tinje than before. You 
 will probably find, if you have been sitting still during 
 your counting, that it beats just about the same from 
 minute to minute, and that you cannot of your own will 
 make it beat faster or slower. Now if you will lie down 
 upon a bench or couch, and breathe very deeply and very 
 slowly for five or ten minutes, and let some one else count 
 your pulse, you will find that it is" slower than it was 
 at your first observation. 
 
 If you take some brisk and vigorous exercise, like run- 
 ning up and down a flight of stairs two or three times, or 
 running around the schoolhouse two or three times, you 
 will find that the heart is beating very much more rapidly 
 and strongly than at your first observation. 
 
 This experiment teaches us two things. First, that we 
 cannot directly control the heart by the will, and, second, 
 that there is something in the body that does control the 
 heart. If we wish to make the heact beat faster, we can 
 do so by making the other muscles of the body exercise, 
 or if we wish the heart to go more slowly, we can accom- 
 plish it by decreasing the work which it has to do for the 
 system, which was done in the expferiment above when 
 you lay down in absolute rest and in a position which 
 reduced the work of the heart. 
 
 The heart, like the stomach, is controlled by the nervous 
 system. There are two sets of nerves which go to the 
 heart from the central nervous system. One of these sets 
 
152 PHYSIOLOGY 
 
 of nerves comes from the sympathetic nervous system, 
 and the other comes direct from the brain through the 
 vagus nerve, which passes down the side of the neck, 
 through the thorax into the abdomen. As the vagi 
 nerves pass the heart, they give off branches to it. The 
 nerves which come from the sympathetic nervous system 
 pass to the heart from the upper ganglia of that system, 
 as shown in the diagram of the sympathetic system (Fig. 
 19, p. 51). 
 
 The nerves which influence the heart are shown in that 
 figure to come from the first dorsal ganglion of the sym- 
 pathetic system of both the right and left side, and also 
 from the right and left vagus. From these various 
 sources, the nerve fibers form a network near the base 
 of the heart, called the cardiac plexis, or heart network. 
 
 The nerve fibers from the sympathetic system cause the 
 heart to go faster, while the nerve fibers from the brain 
 make the heart go more slowly. These two sets of fibers 
 are similar to the lines and whip which the driver uses in 
 driving his horse, — the whip making the horse go faster, 
 and the lines holding him back. If the whip is lost, the 
 horse may go very slowly, and the driver has no way of 
 making him go faster. Similarly, if the sympathetic 
 nerves leading to the heart are cut, the heart will go very 
 slowly, and any urgent need of the system for more blood 
 will not be responded to by the heart, because the only 
 impulse which it can receive from the central nervous 
 system will only make it go more slowly instead of more 
 rapidly. 
 
 On the other hand, if the nerves which the heart re- 
 ceives from the vagus should be cut, the heart would begin 
 to beat very rapidly, and the system would have no means 
 through which to control it ; and like a horse whose lines 
 
CIRCULATION 163 
 
 are cut, it will go faster and faster until a disaster occurs. 
 But when these nerves are all in order, the heart will beat 
 slowly when the tissues of the body heed little blood, and 
 will beat rapidly when the tissues of the body need more 
 food or more oxygen. 
 
 9. THE CONTROL OF THE CIRCULATION (continued) 
 CONTROL OF TISSUE SUPPLY 
 
 In the preceding lesson it was explained how the heart 
 is made to beat more rapidly and strongly when more 
 blood is needed in the tissues, but no mention was made 
 of the very important fact that not all of the tissues need 
 an extra supply of blood at the same time. When one is 
 taking vigorous muscular exercise, he is not likely to be 
 doing much thinking, nor is he likely to be digesting a 
 meal, so it is the muscular system alone that needs an 
 extra supply of food and of oxygen. When the stomach 
 is digesting a meal, it needs an extra supply of blood. It 
 can do its work to better advantage if it can for a time, 
 say for an hour at least, monopolize iii a measure the blood 
 flow, not having to divide with muscles or brain. In order 
 to accomplish this, the system has a very remarkable appa- 
 ratus, which consists of muscles and nerves. The mus- 
 cles are those located in the walls of the arteries, especially 
 in the smaller branches of the arteries, and the nerves are 
 fine fibers from the sympathetic nervous system, which 
 pass to these muscles in the walls of the arteries, and 
 either cause them to constrict the arteries, allowing less 
 blood to pass, or causing them to dilate widely. 
 
 Let us call the nerves which cause them to contract, 
 
154 PHYSIOLOGY 
 
 vessel constrictors, and those which qause the arteries to 
 dilate, vessel dilators. 
 
 When the stomach and intestines receive food which 
 they have to digest, the dilators of the arteries supplying 
 these organs cause the muscles of the arteries to relax, and 
 the supply of blood will be increased in those organs only, 
 while the amount of blood which passes to other organs 
 in the system will be somewhat dimini-shed. 
 
 As another example, when one begins to perform vigor- 
 ous exercise, or do hard work, the dilators of the muscular 
 arteries will cause these arteries to dilate, thus increasing 
 the flow of blood to the muscles. 
 
 The muscles make up so much of the tissues of the 
 body that a dilation of the muscular arteries would cause 
 a considerable fall in the pressure of the blood, if the cen- 
 tral pump, namely, the heart, did not increase the rate 
 and force of its pumping. Thus it occurs that muscular 
 exercise leads always to an increase in the rate and force 
 of the beating of the heart. 
 
 The heart is less modified in its beating by the work 
 which the glandular organs or the brain may have to do, 
 but that is because the glandular organs and brain make 
 up so small a portion of the whole body. 
 
 The influence of these constrictors and dilators upon 
 the arteries may be very readily observed by noticing the 
 skin. When one goes from a warm room, into cold atmos- 
 phere, the skin becomes white, and one feels chilly. That 
 is because the little arteries of the skin have all been con- 
 tracted by the constrictors, thus not allowing the blood to 
 flow into the skin, but keeping it in the deeper organs and 
 tissues. This is nature's method of keeping the blood 
 warm. One's natural impulse, under such conditions, is 
 to hurry, to move briskly. This brisk movement can 
 
CIRCULATION 155 
 
 be carried on only through an oxidation of food materials 
 within the muscle cells. But this oxidation causes heat 
 to be given off to the blood. In a few minutes, if the 
 system is in a perfectly healthy condition, the dilators to 
 the arterioles of the skin will act, and the now heated 
 blood will go into the skin and make it red and warm. 
 If, for any reason, the blood remains, in the skin at first 
 without being withdrawn to the muscles and internal 
 organs, it will be rapidly cooled down before the muscles 
 have had a chance to heat it up through oxidation, as 
 above described, and the temperature of the body will be 
 lowered. 
 
 The nerves which assist in the control of the arteries 
 come from the sympathetic nervous System and are much 
 influenced by the emotions. You have all noticed how 
 the face flushes when one is embarrassed ; this is due to 
 the action of the dilator nerves. Various emotions may 
 ca;use the flushing or blushing, for example, anger and 
 shame. Certain emotions, such as ffear or extreme rage, 
 may cause the constrictors to act, making the face white. 
 
 10. THE HYGIENE OF THE CIRCULATORY FLUIDS AND 
 
 ORGANS 
 
 I. EXERCISE 
 
 When the muscle tissue is at perfect rest the blood 
 stream is comparatively slower, and the pressure of the 
 blood in the capillaries is not sufficient to cause a large 
 amount of plasma to filter through the capillary walls. 
 There is, therefore, a smaller amount of tissue plasma 
 or tissue lymph circulating between the cells. As a 
 further result, the stream of lymph which leaves the 
 
156 PHYSIOLOGY 
 
 muscle tissue by way of the lymphatics is also much 
 decreased during inactivity. And the lymph which 
 makes its way into the lymphatics, having little pressure 
 from the tissue and little or no pressure upon the lym- 
 phatic vessels from muscular contraction, moves only very 
 sluggishly toward the heart. This sluggish flow of lymph 
 during rest permits waste matter to collect in the tissue 
 plasma. 
 
 One or two periods of vigorous mugcular exercise each 
 day will, by increasing the flow of blood and lymph through 
 the muscles, cause all this waste material to be carried 
 out of the muscles to the organs of excretion, where it 
 will be thrown out of the body. 
 
 We see from this how important it is for one to take 
 exercise. The increased strength and rate of the heart- 
 beat during exercise will cause an increased flow of blood 
 in other tissues of the body as well as the muscle tissues, 
 thus insuring the thorough sweeping away of waste 
 material as well as a thorough distribution of the nourish- 
 ment and oxygen contained in the blood. 
 
 Most people who live in cities and towns do not exer- 
 cise enough, and some people exercisb too much. Some 
 people wish to exercise, but there may be reasons why 
 they cannot do so. 
 
 II. MASSAGE 
 
 Such people may substitute massag-e for exercise. The 
 movement of the muscles of an arm or leg, or pressure 
 upon the tissues of arm or leg or body, will cause an 
 increased flow in the lymphatics and veins, even when 
 some one else takes hold of the arm or leg and moves it 
 for one. 
 
CIRCULATION 157 
 
 This passive exercise is called massage, and is an im- 
 portant means of insuring nutrition and an elimination of 
 waste materials in inactive tissues. 
 
 The most efficient kind of massage is kneading of the 
 tissues and rubbing. If a boy has so-called "growing 
 pains," which is really rheumatism from some exposure 
 to wet OF cold, his pains will be much relieved if the 
 aching part is thoroughly rubbed or pressed, always 
 beginning at the most distant part and working toward 
 the heart. 
 
 This will gradually work out the lymph and venous 
 blood from the tissues and cause fresh blood to circulate 
 through the tissues, carrying away irom them those waste 
 materials which are irritating the nerves and causing 
 the pain. 
 
 III. TIME FOE REST AKD TIME FOR WORK 
 
 We found that vigorous exercise takes most of the 
 blood to the muscles. The digestion of a heavy meal 
 takes most of the blood to the digestive system, while 
 heavy brain work takes a large portio>n of the blood to the 
 brain. 
 
 Every one knows that it is impossible to do hard think- 
 ing and hard muscular work at the same time. The 
 reason is, that the muscles take the blood and leave the 
 brain without sufficient supply of nutriment or oxygen to 
 carry on its work vigorously. 
 
 Whenever the muscular system is working hard at the 
 same time that some other system of organs is attempting 
 to do its work, the muscular system, gets the blood, and 
 the other system is robbed of the supply necessary to do 
 its work properly. 
 
168 PHYSIOLOGY 
 
 If one attempts to do heavy work after a heavy meal, 
 he may do the work, but the meal either will lie undi- 
 gested or will digest very slowly. Oft repeated attempts 
 of this kind will so derange the digestive system that it 
 refuses to do its work properly, and we say the person 
 has indigestion or dyspepsia. A very light meal of very 
 easily digested food may be followed almost at once by 
 vigorous exercise, without causing serious injury to the 
 digestive organs. A heavy meal should be followed by 
 at least an hour of rest, or at most very little exercise 
 in the open air. 
 
 IV. THE CONDITION OF THE BLOOD 
 
 You see how important it is for the health and strength 
 of the body that the blood should always contain suffi- 
 cient nutriment for the tissues, sufficient oxygen for tissue 
 oxidation, and should be kept free from accumulated waste 
 materials. 
 
 One of the most frequent diseases of the blood is called 
 anaemia, and consists of a decrease in the number or in 
 the quality of the red blood corpuscles. The red blood 
 corpuscles carry oxygen to the tissues; if these are de- 
 creased in number the tissues will suffer for want of 
 sufficient oxygen. 
 
 The best way to avoid ansemia, or the best way to 
 recover from it, is to eat plenty of nourishing food. It 
 is understood, of course, that the digestive system is in 
 good condition, otherwise the plenty of nourishing food 
 could not be properly utilized by the system. Foods 
 which are rich in iron should form an important part 
 of the dietary ; such foods are eggs, the cereal foods, 
 beans, peas, spinach, and so forth. 
 
CIRCULATION 159 
 
 11. THE INFLUENCE OF NARCOTICS UPON THE CIRCU- 
 LATORY FLUIDS AND ORGANS 
 
 I. THE EFFECT OF ALCOHOL UPON THE BLOOD 
 
 Alcohol is absorbed from the alimentary canal un- 
 changed by the processes of digestion. It passes into the 
 blood vessels in the walls of the stomach and intestines, 
 and is distributed by the blood throughout the system. 
 Dr. Woodhead, Professor of Pathology, Cambridge Uni- 
 versity, England, believes from the work of various 
 medical men, whose authority he quotes, that the white 
 blood corpuscles are injured by the presence of alcohol in 
 the blood, and made less active in their work of defend- 
 ing the system against the germs of disease, therefore leav- 
 ing the system more exposed to various germ diseases. 
 
 II. THE EFFECT OF ALCOHOL UPON THE HEART 
 
 The occasional and moderate use of alcoholic drinks 
 influences the action of the heart. " Wherever a distinct 
 effect is made upon the system by alcohol, this is always 
 indicated by the pulse. The action of the heart is quick- 
 ened for a time, afterward becoming enfeebled until 
 another dose of poison is taken to revive it. In time, this 
 becomes the ordinary condition, and is accompanied by 
 general changes in the action of the whole circulatory 
 system. These changes in the action of the heart and 
 arterioles lead to changes in the structure of the heart 
 and blood vessels."^ 
 
 Professor Destree (" Influence of Alcohol on the Muscu- 
 
 iQeo. H. McMichael, M.D., Buffalo, N.Y., in the Dietetic and Hygienic 
 Gazette, May, 1897, p. 278. 
 
160 PHYSIOLOGY 
 
 lai' System ") believes that the increased action of the heart 
 under the influence of alcohol is only apparently a stimu- 
 lation, resulting partly from the paralysis of the muscular 
 walls of the arterioles, thus allowing them to dilate and 
 reducing blood pressure, which the heart tries to correct 
 by beating more rapidly, and resulting partly from irri- 
 tation of the mucous membrane of the stomach by the 
 alcohol. This irritation affects the heart through the 
 sympathetic nervous system. 
 
 But the heart is not only modified in its action by the 
 influence of alcohol, it is also modified in its structure. 
 " The heart, from continued overaction, becomes dilated, 
 and its valves are relaxed. The membranes which en- 
 velop the organ are thickened, rendered cartilaginous, 
 and occasionally calcareous. The valves, which consist of 
 folds of membrane, lose their suppleness and become 
 diseased and weakened. The muscular fiber of the heart 
 is replaced by fatty cells, so that the power of contraction 
 is greatly reduced. These derangements are liable to 
 cause death from sudden failure of the heart itself, from 
 rupture of the blood vessels, from oozing of the blood in 
 the brain, producing apoplexy. . . . There is always 
 danger of the heart failing to do its work, for alcohol has 
 made it inefficient."-' 
 
 HI. THE EFFECT OF ALCOHOL UPON THE BLOOD VESSELS 
 
 From what has been said in a previous lesson about the 
 muscular walls of the arteries and arterioles, it is plain 
 that it is very important to the system that the arteries 
 retain their power to respond quickly to the needs of the 
 system, now expanding, and now contracting. But under 
 
 IG. H. McMichael, M.D., Journal of Inehriety , July, 1897, p. 258. 
 
CIRCULATION 161 
 
 the influence of alcohol, even when used in moderate 
 quantities for a long period of years, the walls of the 
 blood vessels become changed, especially the arteries and 
 arterioles. The connective tissue of the arteriole wall 
 becomes much increased, thus making the wall thick and 
 inelastic. Frequently lime salts are deposited in this 
 connective tissue, making the wall of the artery brittle 
 and liable to burst when there is any unusual strain put 
 upon it. Now this weakening of the walls of the blood 
 vessels is especially frequent in the arteries of the brain. 
 Upon the occurrence of anything which causes a sudden 
 increase in the heart's action, thus forcibly distending the 
 arteries, rupture is likelj'^ to occur, thus causing hemor- 
 rhage of the brain, taking the form either of apoplexy or 
 paralysis. 
 
 IV. THE EFFECT OF TOBACCO OK THE HEAKT 
 
 Dr. J. W. Seaver, a professor in Yale University, in 
 an article on " The Effects of Nicotine," calls attention to 
 the fact that the heart action is increased when tobacco 
 is being used, that the increase is due, not to stimulation 
 of the heart, but to partial paralysis of the vagi nerves. 
 From previous lessons you know that the vagi nerves hold 
 the heart in check, causing it to reserve its power as much 
 as possible for legitimate emergencies ; now if the vagi 
 nerves are paralyzed, the heart beats rapidly, thus unneces- 
 sarily wearing itself out. With this information we can 
 easily understand how in the beginning of the habit of 
 smoking, the influence of the nicotine causes so much 
 disturbance to the circulation, for the vagus is the great 
 controlling nerve of the heart, and that organ is the first 
 to respond to the poison. 
 
162 PHYSIOLOGY 
 
 REVIEW OF THE CIRCULATION 
 
 1. The body needs a system of tubes through which the liquids of 
 the body can circulate, just as much as a city needs a system of tubes 
 and pipes through which the water can circulate and the drainage 
 and sewage be carried away. 
 
 2. The blood and lymph are the liquids which circulate through the 
 body. The blood is composed of plasma in which float red and white 
 cells or corpuscles. The lymph is composed of plasma in which float 
 white cells or corpuscles. 
 
 3. The blood and lymph carry food to the working cells, tissues, and 
 organs of the body. 
 
 4. The blood and lymph carry waste matter from the working cells, 
 tissues, and organs of the body to the place where this matter is to be 
 thrown out of the body. 
 
 5. If a blood vessel is cut, the blood clots or coagulates and stops the 
 wound, unless a large artery or vein is cut. 
 
 6. The blood is carried to difEerent parts of the body in arteries 
 and brought back in veins. It oozes through fine capillaries as it 
 passes through the different tissues. 
 
 7. The heart pumps the blood through the arteries, capillaries, and 
 veins. Each contraction of the heart — each heartbeat — sends blood 
 into the arteries. Valves at the entrance of the aorta keep the blood 
 from flowing back into the heart while the heart is being filled with 
 the blood from the veins. 
 
 8. When the heart forces blood into the arteries, it stai-ts a little 
 wave along all the arteries. One can feel this wave wherever the 
 arteries come near to the skin. This wave is called the Pulse. Where 
 may pulses be felt? 
 
 9. The blood carries oxygen from the lungs to the tissues, and car- 
 bon dioxide from the tissues to the lungs. 
 
 10. The heart is controlled by two sets ofnerOes : one set (sympathetic') 
 makes it beat faster and stronger, while the other (vagus) makes it 
 beat more slowly. If the vagus be stimulated, the heart will beat 
 more slowly ; if the sympathetic nerve be stimulated, the heart will 
 beat more rapidly. If the vagus be cut or narcotized, the heart will 
 beat faster; if the sympathetic be narcotised, the heart will beat 
 more- slowly. 
 
REVIEW OF THE CIRCULATION 163 
 
 11. The arteries are controlled hy two sets of nerves. The Constrictors 
 make the arteries smaller and allow less blood to flow into the tissues. 
 The Dilators make the arteries larger and allow more blood to flow 
 into the tissues. 
 
 12. When one exercises hia muscles, the vessel dilators allow more 
 blood to flow to the muscles. The heart als6 works harder and sends 
 a faster current of blood over the body. One should not exercise 
 severely just before or just after a meal. Every one needs exercise in 
 the open air. 
 
 13. Nourishing food and out-of-door exercise, with well-ventilated homes 
 and schoolrooms, will keep the blood pure and the body healthy. 
 
 14. People who use alcohol are more subject to disease than are those 
 who do not; because the body, especially the blood, is less resistant to 
 the germs of disease. 
 
 15. Alcohol makes the heart beat faster ; because it narcotizes or duUs 
 the influence of the vagus nerve. Explain how this can be. 
 
 16. Alcohol makes the blood vessels of the skin dilate, and so the skin 
 looks red and the person feels warm; but the blood gives up its 
 warmth to the air, and the temperature of the body falls. Alcohol 
 also causes the walls of the blood vessels to become weak. 
 
 17. Tobacco causes the heart to beat faster than usual because the 
 vastus nerve is narcotized. 
 
CHAPTER Vn.~ RESPIRATION — HOW THE 
 BLOOD IS PURIFIED 
 
 1. THE NEED FOK A RESPIRATORY SYSTEM 
 
 In our study of the plant we found that oxygen is 
 necessary for its life processes ; that the energy required 
 by the little germinating plant to push aside the little 
 particles of soil and appear above the surface of the 
 ground, can be obtained only b)^ oxidation of some of the 
 plant material. 
 
 The oxygen which enters into the oxidation comes from 
 the atmosphere ; the material oxidized is part of the plant 
 body, and the result of the oxidation is liberated energy 
 and waste products, comprising in the plant especially 
 water and carbon dioxide. 
 
 In a one-celled animal such as the amoeba, we found 
 the same general principles to be true, and that every 
 motion of the amoeba required an oxidation of a portion 
 of the substance of the little animal, the oxygen coming 
 from the surrounding medium, the oxidation resulting in 
 the formation of waste products, among which carbon 
 dioxide and water take a prominent part. 
 
 Every active cell in our bodies requires oxygen in order 
 to enable it to do its appointed work. If it is a muscle 
 cell, the energy of heat and motion which it must generate 
 for the body can only come from the oxidation of muscle 
 cell protoplasm or muscle cell sap. If the cell is a gland 
 cell, it cannot do its work of forming new substances with- 
 out the presence of oxygen, which takes part in the changes 
 
 164 
 
EESPIRATION 165 
 
 that the cell makes in the substances which it absorbs 
 from the blood. If it is a brain cell, oxygen is just as 
 necessary, though perhaps used in somewhat smaller quan- 
 tities than would be the case in a muscle cell. 
 
 Respiration is the process of furnishing oxygen to the 
 active cells of the body. The one-celled plants and ani- 
 mals need no apparatus to carry the oxygen to the differ- 
 ent parts of their system, because their minute bodies are 
 surrounded either by the atmosphere, which is one fifth 
 oxygen, or by water, in which oxygen from the atmosphere 
 is freely dissolved. But in all animals except the simplest 
 ones, large portions of the body are so far removed from 
 contact with the atmosphere or water that these animals 
 require a special apparatus or system of organs devoted 
 to this work of supplying the inside tissues of the body 
 with oxygen. This function is called respiration, and the 
 system of organs which performs this function is called 
 the respiratory system. 
 
 Animals that live in the water breathe by means of gills ; 
 animals that live on land breathe by means of lungs. 
 Some animals live in the water when they are young, and 
 change and turn into land animals when they reach ma- 
 turity. Such an animal is the frog : the tadpole breathes 
 with gills, but the frog breathes with lungs. Some ani- 
 mals which live in the water do not remain under water 
 long at a time. The turtle and the crocodile are water 
 reptiles which breathe by means of lungs. The Avhale, 
 the seal, and the walrus are water mammals that breathe 
 with lungs ; none of these animals can stay under water 
 for a long period. 
 
 Every one has seen the gills of a fish, and will remem- 
 ber that they are composed of delicate, velvety branches 
 which are protected behind a scalelike shield on the side 
 hall's puts. — 11 
 
166 PHYSIOLOGY 
 
 of the fish's head. The fish draws water into the mouth, 
 and closes the mouth, but instead of swallowing the water, 
 presses it out the sides of the pharynx so that it passes 
 over the gills which absorb the oxygen held by the water 
 in solution. 
 
 The lungs are elastic air sacs, which are made of very 
 delicate tissue and lodged within the body cavity. The 
 animal draws the air into the lungs, where it remains for a 
 short time giving up its oxygen to th*e blood which is cir- 
 culating Avithin the capillary branches of the pulmonary 
 artery. The drawing in of the air is called Inspiration, 
 and the throwing of the air out of the lungs is called 
 Expiration. 
 
 That part of respiration which includes the inspiration 
 of the air, the absorption of the oxygen, and the expiration 
 of the air laden with carbon dioxide, is called external res- 
 piration, while that part of the respiration which includes 
 the distribution of the oxygen to the tissues by the blood 
 and the absorption of the oxygen from the blood by the 
 tissues, also the giving up of carbon dioxide to the blood 
 by the tissues and the transportation of this carbon 
 dioxide gas by the blood to the lungs, is called internal 
 respiration. 
 
 2. THE ORGANS OF RESPIRATION 
 
 The lungs have already been mentioned as organs of 
 respiration, and they are the most important organs of the 
 respiratory system. Figure 39 shows the lungs -within the 
 chest or thorax. Notice from the figure that there are 
 two lungs, one on either side of the heart. These lungs 
 are hollowed out to make a space for the heart. 
 
 The pulmonary artery (2)) branches under the arch of 
 the aorta, sending part of the blood to each lung. The 
 
RESPIRATION 
 
 167 
 
 heart is not in the middle of the thorax, but just a little 
 more on the left side than on the right, so that the left lung 
 is a little smaller than the riglit lung. The two lungs and 
 the heart rest upon the muscular partition which separates 
 the thorax from the abdomen. Tliis muscular partition is 
 
 Fig. 39. — The cavity of the chest, showing the positious of the heart and the 
 lungs. A, left lung; B, heart; D, pulmonary artery; E, trachea, or wind- 
 pipe. [Tracy.] 
 
 called the diaphragm. Notice from the picture that the 
 diaphragm is higher in the middle than at the edges; in 
 other words, it is arched upward. As the diaphragm is 
 the principal muscle for drawing air into the lungs, we 
 must name it among the respiratory organs. The air is 
 carried to the lungs through a large tube in the neck 
 called the windpipe, or trachea. Thp upper part of the 
 
168 PHYSIOLOGY 
 
 trachea is the larynx, or Adam's apple which one can feel 
 in the throat. 
 
 The air in passing into the trachea must pass through 
 the ^pharynx, and to get into the pHarynx it must pass 
 through either the mouth or nose. Nature intended that 
 the nose should be the air passage, but many people 
 breathe through the mouth because of some temporary 
 or permanent obstruction in the nose. The nose is made 
 especially for breathing ; it is provided with a moist 
 mucous membrane for catching the dust ; it is full of 
 blood vessels for warming the air. To assist in catching 
 the dust, there are, near the opening of the nose, hairs 
 kept moist by secretions. The passage through the nose 
 is not simply a cylindrical canal, buf very irregular, with 
 folds which increase the surface, and not only aid in 
 warming the air and removing the dust, but also aid 
 the sense of smell by increasing the amount of surface 
 exposed to odors. 
 
 The larynx contains the vocal cor.ds, and is the organ 
 for producing the voice, and so is sometimes called the 
 voice box. One can feel the little point of his larynx, 
 and by passing the iingers along the throat below the 
 larynx he can feel the large, stiff tube whose walls con- 
 tain little rings of cartilage. The object of these rings is 
 to keep the trachea open. If it were not for these the 
 trachea would collapse, and the breath would be shut off. 
 
 Notice that down in the thorax between the two lungs 
 the trachea branches into two parts, each looking quite 
 like the trachea, only smaller (Fig. 40). These two 
 parts are bronchi. Each bronchus subdivides within the 
 lung into a series of treelike branches, until finally every 
 portion of the lung substance is reached by minute ter- 
 minal twigs of this system of branches. The divisions of 
 
RESPIRATION 
 
 369 
 
 the bronchi are called bronchial tiebes. The bronchial 
 tubes end in clusters of air cells, which are similar to 
 bunches of grapes. In the figure only a few of these 
 clusters are shown, but the lung is made up largely of 
 innumerable clusters lying side by si^le. 
 
 The air passages consist, then, of nose, pharynx, larynx, 
 trachea, bronchi, bronchioles, and air cells. All of the air 
 passages are lined with mucous membrane. The mucous 
 membrane of trachea, bronchi, and bronchioles is provided 
 with ciliated cells. These cilia are always moving with an 
 
 FiQ. 40. — Air passages in tlie human lungs, a, larynx ; b, trachea ; 
 0, d, Ijrouchi ; e, bronchial tubes ; /, cltister of air cells. 
 
 upward, whiplike motion, which carries particles of dust 
 and mucus up the trachea until it reaches the larynx, 
 where it causes a tickling sensation and is coughed up. 
 
 The branches of the pulmonary artery pass into the 
 lungs by the side of the bronchi, and subdivide wherever 
 the bronchi subdivide, being finally distributed in small 
 branches to each cluster of air cells. The end branches 
 of the pulmonary artery send to each cluster one or more 
 
170 PHYSIOLOGY 
 
 arterioles, which break up into a network of capillaries 
 similar to that shown in Figure 35, so that each air cell is 
 surrounded by a network of capillaries. 
 
 "We must not forget that the pulmonary artery carries 
 impure blood to the lungs for purification, so that the 
 arrows in Figure 36 will need to be reversed, the impure 
 blood passing in from the arterioles and becoming purified 
 as it passes through the capillary system, and then, pass- 
 ing out into the pulmonary veins, finally collects into four 
 pulmonary veins which empty into the left auricle. 
 
 The blood which circulates in the lung capillaries is 
 separated from the air by the delicate mucous membrane 
 of the air cell, the capillary wall, and a film of plasma ; 
 yet we shall find that there is ample opportunity for the 
 blood to be purified. 
 
 3. THE MOVEMENTS OF RESPIRATION 
 
 The diaphragm has already been mentioned as the 
 most important muscle of the respiratory system. Refer- 
 ence to Figure 39 will show the diaphragm arching upward, 
 filling the space in the middle of the thorax and passing 
 up to the heart. The lower lobes of the lungs fill the 
 space between the high dome of the diaphragm and 
 the wall of the thorax. Just below the diaphragm lie the 
 stomach and liver, not shown in the figure. 
 
 The muscular fibers of the diaphragm radiate outward 
 from its center and are attached around the thoracic wall. 
 The contraction of the diaphragm is brought about by 
 all these fibers contracting at the same time. It must be 
 easily seen that when the diaphragm contracts its dome 
 will be flattened. Now the diaphragm is the partition 
 wall between the thorax and the abdomen. The flatten- 
 ing of the diaphragm is really a moving of all the dia- 
 
RESPIRATION 171 
 
 phragm except its margins from the thorax toward the 
 abdomen. That would tend to make more room in the 
 thorax, and also to push the stomach and liver downward 
 further into the abdominal cavity. 
 
 What would happen in the abdominal cavity is very 
 easily understood. The stomach and liver pusli upon the 
 intestine and all of these organs are pressed outward in 
 every direction, and so distend the walls of the abdomen. 
 
 It may not be so easy to understand just what takes 
 place within the thorax. We know' that when we draw 
 up the piston of a syringe the air or water will rush 
 through the nozzle of the syringe and fill up the space 
 that would be left, so that there is really no vacant space 
 in the syringe, that is, no vacuum. 
 
 In a similar way, when the diaphragm pulls downward 
 toward the abdominal cavity it would tend to leave a 
 vacuum around the lungs and heart, but the air rushes 
 iu at the nose and through the air passages, filling the 
 lungs and allowing them to expand and fill up all of the 
 space made by the contraction of the diaphragm. 
 
 The diaphragm is not the only mxiscle of respiration ; 
 the diaphragm makes only one wall of the thorax, a 
 partition wall between the thorax and another body 
 cavity. The outside walls of the thorax are also mov- 
 able, though in a much smaller degree than is the case 
 with the diaphragm. The curving ribs slant downward 
 and forward from the backbone, and are so attached to 
 the backbone that when the front ends are raised, tlie 
 front wall of the chest, as well as the side walls, will be 
 thrown out, thus increasing the space within the thorax, 
 which the lungs swell out and fill (Fig. 41). The mus- 
 cles which do this are the muscles which pass from the 
 backbone to the collar bone and upper ribs, also the inter- 
 
172 
 
 PHYSIOLOGY 
 
 costal muscles, which attach each rib to the next rib 
 below it. 
 
 The filling of the lungs is called inspiration. The lungs 
 are alternately filled and emptied. The emptying of the 
 lungs is called expiration. When the lungs are to be 
 
 p ei„ 
 
 
 (; 
 
 a/ 
 
 
 
 
 " 
 
 A 
 
 
 1 
 
 
 III 
 
 Fig. 41. — Diagram illustrating the increase in the diameter of the thorax 
 when the ribs are raised. 
 
 emptied tlie diaphragm relaxes, and the muscles which 
 have raised the ribs relax, the chest walls fall back to 
 their position of rest; the abdominal walls, which Iiave 
 been distended by the pressure of th^ organs within come 
 back to their position of rest, which pushes the diaphragm 
 up into the thorax again, thus restqring to its position 
 of rest all the muscles of respiration, and the ribs as well as 
 the lungs. As the walls of tlie thorax pass inward toward 
 the lungs, they contract, and the air flows out of the nose. 
 
 4. THE MOVEMENTS OF RESPIRATION {^continued) 
 I. FOECED BREATHING 
 
 The breathing described in the preceding lesson is 
 what is called quiet breathing. This is the way one 
 breathes wlien he is sitting quietly or when asleep. The 
 air which flows out and in the lungs in quiet breathing is 
 called tidal air., and amounts to about 30 cubic inches, 
 or a little over a pint, for the average-sized adult man. 
 
KESPIRATXON 173 
 
 If one will observe his respiration when he is breathing 
 quietly he will get a good idea of how much air flows 
 out of and into the lungs, and how much movement of 
 the chest and abdomen there is in quiet breathing. At 
 the end of a quiet inspiration one is able to continue to 
 draw air into the lungs. He can g*o on expanding his 
 chest and abdomen until he reached the limit of his 
 capacity, drawing in about 100 cubic inches more of 
 air. This extra air which one is able to draw into the 
 lungs in a forced inspiration is called complemental air. 
 In forced inspiration, all of the muscles of quiet inspira- 
 tion are in use, contracting much more strongly than in 
 quiet breathing, and besides these, muscles of the back 
 and shoulders assist in raising the ribs and sternum. 
 
 If, at the end of a forced inspiration, one begins to let 
 the air flow out of the lungs, the 100 cubic inches of com- 
 plemental air will flow ont first, followed by the 30 cubic 
 inches of tidal air. After these 180 cubic inches have es- 
 caped from the air passages and the muscles of respiration 
 are in position of perfect rest,- one may still force air out 
 of the lungs. This is called forced expiration, and is ac- 
 complished mostly by the contraction of the walls of the 
 abdomen. This forces the intestines, stomach, and liver 
 backward and upward against the diaphragm, thus forc- 
 ing the diaphragm farther up into the chest cavity and 
 forcing air out of the lungs. This air of the forced ex- 
 piration is called reserve air, and amounts to about 100 
 cubic inches, but there is still remaining in the lungs air 
 which one cannot force out voluntarily. This air that 
 always remains in the lungs is called residual air, and 
 amounts to about 100 cubic inches. Though this residual 
 air cannot be voluntarily forced out, it is sometimes forced 
 out accidentally. If one falls upon his shoulders, or if 
 
174 
 
 PHYSIOLOGY 
 
 '0ompIcinental 
 i Air 
 '■X/, luo eii. ill. 
 
 t 
 
 Tidal Ail- 
 so cu. in. 
 
 through any accident the chest is sud(;lenly compressed at 
 the end of an expiuation, a portion of the residual air may 
 be forced out. In such a case one feels distressed and 
 has difficulty in regaining the breath. 
 
 Figure 42 shows the relative amounts of tidal, com- 
 plemental, reserve, and residual 
 air. It will be seen from the 
 diagram that the amount of air 
 which one can expel from the lungs 
 after forced inspiration would 
 equal about 2^0 cubic inches. This 
 is called the lung capacity and is 
 the average amount for an adult 
 man 5 feet 8 inches in height. 
 For each added inch in height 
 the lung capacity would increase 
 about 9 cubic inches ; and for 
 persons shorter than the average 
 the lung capacity would decrease 
 9 cubic inches for each inch of 
 height below the average. The 
 average boy of fourteen would 
 have a lung capacity of about 120 
 cubic inches ; the girl of four- 
 teen should have about the same 
 lung capacity as a boy of that 
 age, but the average woman has 
 a smaller lung capacitj'' than the 
 average man. 
 
 is'- " 
 
 Reserve 
 
 Air 
 100 cu. in. 
 
 _^ 
 
 Fig. 42. — Diagram showing 
 the relative amounts of 
 tidal, complemental, reserve, 
 and residual air. Note that 
 the brace shows the average 
 lung capacity for the adult 
 man. 
 
 II. CHEST AND ABDOMINAL BKEATHING 
 
 It is frequently said that women breathe differently 
 from men, the chest movement being more pronounced in 
 
KESPIEATION 175 
 
 a woman and the abdominal movement in a man. The best 
 authorities agree now that there should be no difference 
 in the breathing of men and women ; if there is a differ- 
 ence it is because of the unhygienic clothing so frequently 
 worn by women. 
 
 5. BREATHING AND THE VOICE 
 I. HOW THE BREATHING IS CONTROLLED 
 
 The movements of the diaphragm are controlled by 
 the phrenic nerves, which can be traced upward from the 
 thorax and the deep muscles of the ueck into the spinal 
 cord and up to the medulla oblongata, situated at the base 
 of the brain. 
 
 The intercostal muscles are controlled by the inter- 
 costal nerves, each one of which patjses directly into the 
 spinal cord and upward to the medulla. These are the 
 nerves which control the muscles of inspiration. The 
 lower intercostal muscles which control the muscles of 
 the abdominal walls are expiration nerves. 
 
 The sensory nerves of the nose and those branches of 
 the vagus nerve which supply the larynx and the mu- 
 cous membrane of the lungs, are the sensory nerves of 
 respiration. 
 
 II. MODIFICATIONS OP BREATHING 
 
 If mucus or any foreign body gets into the larynx it 
 irritates the sensory nerves, a message is sent to the 
 breathing center in the medulla, from which a message is 
 sent to the abdominal muscles, which contract quickly, 
 causing a coughing, which dislodges and ,throws out the 
 offending substance. 
 
176 PHYSIOLOGY 
 
 When the membrane of the nose is irritated in any way, 
 a similar explosion of the air through the nose will gen- 
 erally remove the irritating matter. This act is called 
 sneezing. 
 
 Yawning is a deep inspiration in which the lungs are 
 well filled and inflated, furnishing an extra supply of 
 oxygen for the system. 
 
 Hiccoughing consists of a sudden contraction of the dia- 
 phragm, which causes a spasmodic inspiration ; this is 
 blocked by the sudden closure of the larynx, causing a 
 "hiccough." 
 
 Sighing is similar to yawning but is caused by such 
 emotions as grief or sorrow. 
 
 Grying and Laughing. These are combined modifica- 
 tions of breathing and the voice. They are caused by the 
 emotions, and consist of a deep inspiration, usually fol- 
 lowed by a series of spasmodic expirations which are 
 vocalized or in which the voice is acting. 
 
 Sobbing is a convulsive inspiration, also emotional, and 
 usually follows prolonged crying. 
 
 III. THE VOICE 
 
 In describing the organs of respiration the larynx or 
 voice box was mentioned. In the upper part of the 
 larynx two membranes pass out from the sides toward the 
 middle. The edges of these membranes are rounded 
 cords which are so attached to the walls of the larynx 
 that they may be brought close together and stretched 
 tightly through the contraction of the muscles in the wall's 
 of the larynx. These cords are the vocal cords. When 
 the vocal cords are tightened and brought near together, 
 the air passing over them sets them to vibrating. This 
 
RESPIRATION 177 
 
 vibration causes a sound which we call the voice. Most of 
 the higher animals have a voice. Animals that have a 
 voice use it in the expression of their emotions and desires 
 first of all. A child first uses its voice for this purpose. 
 When it begins to talk it expresses other ideas. 
 
 Man has cultivated his voice along with his mind, so 
 that he is able to express, not only the emotions and 
 desires, but a continuous train of thought in a succes- 
 sion of sounds which we call speech. These sounds are 
 grouped into syllables and words; each syllable contains 
 at least one vocal or vowel sound wtiich is made by the 
 larynx and which is more or less modified by the organs 
 of articulation. These modifications of the vocal sounds 
 are termed consonants, and they are- produced by the vari- 
 ous positions of the lips, tongue, teeth, and palate during 
 the formation of the sound by the larynx. 
 
 In the word or syllable bat, the larynx makes the vocal 
 or vowel sound a, and this vowel sound is introduced by 
 the lip consonant (labial) J, and followed by the tongue- 
 palate consonant (palato-lingual) t. 
 
 The vowels of the English language are a, e, z", o, and m, 
 which may be modified in quality by the vocal organs to 
 make about seventeen different sounds. 
 
 The consonants, about twenty-one in number, are sub- 
 divided into the labial or lip consonants, p, b, w ; the 
 labio-dental or lip-teeth sounds, /, v ; the linguo-dental or 
 tongue-teeth sounds, th; the nasals, m, n, ng ; and the 
 palato-linguals or palate-tongue sounds. 
 
 People of culture and refinement usually possess voices 
 which are under perfect control under all circumstances, 
 never pitched too high or too low ; when they speak 
 their voices are well modulated and their words are dis- 
 tinctly enunciated. 
 
178 PHYSIOLOGY 
 
 6. HOW THE AIR IS CHANGED IN THE LUNGS 
 I. THE COMPOSITION OF THE AIK 
 
 AiK is a mixture of gases. The mixture is composed 
 chiefly of nitrogen (about four fifths), oxygen (about one 
 fifth), with a very small amount of carbon dioxide. There 
 are minute portions of other gases, because other gases 
 than those mentioned above are escaping into the atmos- 
 phere as tlie result of various natural phenomena; some sul- 
 phurous and other gases may escape from volcanoes, and 
 what is called marsh gas escapes from decaying vegetable 
 matter in swamps. There escape into the atmosphere 
 which is over great cities and manufacturing centers, large 
 quantities of various gases, among them illuminating gas, 
 and sulphurous gases from the combustion of low grades 
 of coal, also quantities of carbon monoxide gas and of 
 ammonia gas. But when one remembers that the atmos- 
 phere is at least forty miles deep over the whole earth, and 
 that it is being constantly stirred up by the winds, and 
 that the noxious gases are gradually dissolved in the sur- 
 face waters of the earth, and that the carbon dioxide gas 
 is being consumed by the plants for food, it must be clearly 
 seen that the proportion of these noxious gases in the 
 general atmosphere is too slight to take into consideration. 
 
 Besides all of the gases which go to make up the atmos- 
 phere, there is the water of the atmosphere, which is a 
 most important constituent, but which is not usually in- 
 cluded among its gases. Most of the water of the atmos- 
 phere is in the form of an invisible vapor which the 
 atmosphere takes up from the surface water of the earth. 
 Warm air takes up more than cold air. In your physical 
 geography you will learn that when warm air which is 
 
RESPIRATION 179 
 
 saturated with invisible moisture is cooled, the moisture 
 collects in minute drops which gather in a visible cloud. 
 When one breathes into the cold winter air he can see 
 the cloud of vapor passing from his nostrils. This vapor 
 is invisible while it is in the air passages, and becomes visi- 
 ble only when it passes out into the cold air, where the 
 moisture is collected into drops. The clouds that float 
 through the air are masses of visible vapor. The moisture 
 of the atmosphere is very important to consider in the 
 hygiene of the lungs. 
 
 The nitrogen of the atmosphere is colorless, tasteless, 
 odorless, and is one of the most inactive gases known to 
 chemists ; the oxygen of the air is also colorless, odorless, 
 and tasteless, but is the most active gas known to chemists, 
 and is the most universal in its combination with other 
 elements, so that it enters into the composition of the 
 water which covers so large a part of the earth's surface 
 and, practically, every rock in the earth's crust, and forms 
 a large part of every plant and animal living upon the 
 earth. Our studies in the physiology of plant and animal 
 nutrition teach us that it is through tlie combination of 
 oxygen with the tissue elements that all plant and animal 
 energy is liberated or generated. 
 
 II. THE CHANGES WHICH THE ATMOSPHERE UNDERGOES 
 IN THE LUNGS 
 
 We take air into the lungs for its oxygen. When air 
 is drawn into the lungs but once and exhaled in a normal 
 way, it loses about one fourth of its oxygen. If the air 
 lost the same amount when rebreathed, all of the oxygen 
 would be consumed if the same aii' were breathed four 
 times. But when tlie air is rebreathed, only one fourth of 
 
180 PHYSIOLOGY 
 
 the remaining oxygen is absorbed ; thus less and less is taken 
 at each rebreathing of the air. And if one were shut into 
 a very small space, he would take out one fourth of the 
 oxygen in breathing the air the first time, and about one 
 fourth of the remainder the second time, and so on, always 
 taking one fourth of the remainder at each successive 
 rebreathing of the air, until finally nearly all the oxygen 
 would be exhausted. The death of the individual would 
 soon follow, of course. 
 
 Resides the change in the oxygen, carbon dioxide is 
 added to the air. A little smaller quantity of the carbon 
 dioxide is added than enough to make up for the oxygen 
 which is taken away, so that the air exhaled is a little 
 less in quantity than the air inhaled when measured 
 under the same conditions. 
 
 If the inspired air is dry it will take up moisture from the 
 air passages ; and so carry awaj^ a certain amount of water 
 from the system. It will always carry away water from 
 the system unless it has the same temperature as the air 
 passages, and is saturated with water at that temperature. 
 
 Besides the subtraction of oxygen and the addition of 
 carbon dioxide and water, there is a change of tempera- 
 ture, the exhaled air being warmed to nearly the tempera- 
 ture of the blood, and there is also an addition of a small 
 amount of organic matter carried away from the air 
 passages. 
 
 7. HOW THE BLOOD IS CHANGEp IN THE LUNGS 
 I. HOW THE BLOOD IS OXYGENATED 
 
 It has been stated in a previous lesson that the work of 
 the red blood corpuscles was to carry oxj^gen from the 
 lungs to the tissues. The first question which arises is, 
 
RESPIRATION 
 
 181 
 
 how does the oxygen get from the air cells of the lungs to 
 the red blood corpusbles ? •• When a gas is in contact with 
 the surface of a , liquid, directly or through a moist mem- 
 brane, the' gas will ' pass into the liquid direct or through 
 the membrane, xapidly at first, and more slowly later, 
 until there is.no more absorption of the gas, when we say 
 the liquid is saturated. If the liquid is flowing past the 
 membrane, the process of absorption o/ the gas will go on 
 at the same rate, because the liquid is continually renewed. 
 
 Between the air in the air cell and the red blood cor- 
 puscles in the capillaries of the lungs there intervene 
 (1) the thin membranous wall of the air cell, (2) a thin 
 submucous coat whose 
 spaces are filled with 
 lymph, (3) the wall of 
 ■the capillary, (4) the 
 plasma within the capil- 
 lary. Then comes the red 
 blood corpuscle (Fig. 
 ■43, a). 
 
 Every space between 
 fibers and cells is filled 
 with plasma or lymph 
 and the cells themselves 
 are composed largely of Fio. 43, 
 water, so that the oxygen 
 readily passes through 
 the membranes and flu- 
 ids just mentioned, and 
 finally reaches the red 
 blood corpuscle which is floating along in the capillary. 
 
 Now red blood corpuscles have a strong affinity or 
 appetite for oxygen, and immediately take up from the 
 
 Bronchiole 
 Diagram of two air cells, show- 
 ing the capillary network which coyers 
 them, and at a the structures which 
 intervene between the air and the blood 
 are indicated: 1, mucous membrane of 
 the air cell ; 2, submucous meshwork ; 
 3, wall of capillary ; i, plasma in capil- 
 lary ; 5, red ^lood corpuscle. 
 
182 PHYSIOLOGY 
 
 plasma the oxygen which comes in, and pass on, leaving 
 the plasma as poor in oxygen as it was to start with ; so 
 tliat more oxygen readily passes into the capillary, and 
 finds the plasma and corpuscles ready to take it up at 
 once and carry it off to the tissues. 
 
 II. HOW THE BLOOD IS FEEED OF CARBON DIOXIDE 
 
 The blood leaves the tissue with a heavy load of carbon 
 dioxide, which is carried away from the tissues to be 
 thrown out of the system. This carbon dioxide is carried 
 partly by the red blood corpuscles and partly by the 
 plasma of the blood. 
 
 If a pint of venous blood were to be put under an air 
 [)ump, and a vacuum made over it, carbon dioxide would 
 pass off from it, and if this were measured at standard 
 atmospheric pressure find at zero degrees, there would be 
 forty-five or forty-six per cent as great volume of gas as 
 there was volume of blood. 
 
 If arterial blood were tried in the same way, a volume 
 of carbon dioxide equal to about fofty per cent of the 
 volume of the blood could be drawn off. 
 
 From this it seems that the blood always has carbon 
 dioxide in it, carrying a big load from the tissues to the 
 lungs and a somewhat smaller load from the lungs back 
 to the tissues, so that it gives up only about one ninth ot 
 this load in the lungs. 
 
 Whether this carbon dioxide gas is given up from the 
 corpuscles or from the plasma is not known, and part is 
 probably given from each. The reason the carbon dioxide 
 gas leaves the blood and passes into the air cells of the lungs 
 is because there is very little carbon dioxide gas in the air 
 cells of the lungs and a great deal iij the blood, and so it 
 
RESPIRATION 183 
 
 naturally diffuses toward the lungs ; and during the time 
 the venous blood is passing through the capillaries, one 
 ninth of the carbon dioxide will have time to diffuse into 
 the air cells, while the red blood corpuscles are taking 
 their load of oxygen for the tissues. 
 
 8. TISSUE RESPIRATION AND BODY HEAT 
 
 The real object of the whole process of respiration is to 
 furnish oxygen to the tissues and to carry away from the 
 tissues the carbon dioxide. Each cell is neither able to 
 build up its own protoplasm nor to do its special work with- 
 out oxygen. When the supply of oxygen stops, all work 
 stops. The active tissues always want oxygen, though 
 they may want more oxygen at one time than at another. 
 The harder they work, the more oxygen they want; when 
 one is doing hard, muscular work, or e.xercising vigorously, 
 the muscles all over the body call for more oxygen. They 
 make this call through the help of the sympathetic ner- 
 vous system. This causes the respiratory muscles to act 
 more vigorously, so that the breathing is deeper and more 
 rapid, more oxygen is brought into the lungs, more is 
 taken up by the blood. 
 
 At the same time that the lungs are working harder, 
 the heart is working harder, thus making a more rapid 
 stream of blood through the lungs, and this takes up the 
 oxygen more rapidly, so that the amount of oxygen 
 carried in any particular quantity of blood during exercise 
 need not be greater than that carried by the same quantity 
 of blood during rest. 
 
 The affinity or appetite of the tissues for oxygen is 
 always stronger than that of the red corpuscles, so that 
 when a corpuscle comes to the capillaries and moves 
 hall's puts. — 12 ^ 
 
184 PHYSIOLOGY 
 
 slowly along them between active tissue cells on either 
 side which are calling for its load of oxygen, it has to 
 part with this load and return by way of the veins to the 
 lungs for another load of oxygen. Active muscle, gland, 
 and nerve cells are constantly giving off carbon dioxide 
 into the tissue plasma which surrounds the cells. The 
 blood in the capillaries has less carbon dioxide than that 
 outside of the capillaries in the tissue, so that carbon 
 dioxide diffuses from the tissue plasma into the blood 
 plasma, and thus loads the blood with carbon dioxide, 
 which is carried by way of the veins to the lungs, and 
 there given up in the way described above. 
 
 I. BODY HEAT 
 
 Aristotle believed that the heat of the body was made 
 within the heart by a combination of the " vital spirits " 
 with the blood. For over two thousand years it was be- 
 lieved that the heat of the body was generated in the blood. 
 
 Lavoisier, who discovered oxygen and the principles of 
 oxidation, believed that heat was generated in the blood 
 of the lungs where the oxygen first entered it. After his 
 time, and until recently, the heat was believed to be 
 generated within the capillaries of the active tissues ; but 
 since the importance of the cell has become understood, it 
 is generally believed that nearly all, if not quite all, of 
 the Oxidation of the substances of t*he body takes place 
 within the living cells, so that the active tissue cells, 
 whose substance is being oxidized, are tlae heat generators. 
 
 The muscle tissue comprises four fifths of the active 
 tissue of the body. Muscle tissue is always generating 
 heat energy, and some of the time it is generating both 
 heat and motion. As the blood circulates through the 
 
RESPIRATION 185 
 
 muscles it becomes heated, and then flowing to other 
 parts of the body it distributes this heat so that all parts 
 of the body are kept warm, the deeper tissues of the 
 body being kept warmer than those near the surface. 
 The temperature of the body is regulated partly by the 
 regulation of the rate of heat generation and partly by the 
 regulation of heat radiation from the* body. The body is 
 giving up heat to the cooler atmosphere all the while. As 
 much as three fourths of all the energy of our food is re- 
 quired to keep the body warm ; the rest is devoted to 
 body building and to the movements and other activi- 
 ties. If one goes out into the cold winter air, the blood 
 at first withdraws to the deeper tissues, then is sent to the 
 muscles, where an extra supply of heat is being generated, 
 and after being warmed in the muscles, passes to the skin 
 to warm the surface of the body. If the body becomes 
 too warm, the blood will go to the skin, and the sweat 
 glands of the skin will pour out perspiration upon the 
 surface, and so the body will be quick.ly cooled. 
 
 Thus we see that these two things working together, 
 heat generation and heat radiation, keep the body contin- 
 ually at nearly the same temperature. 
 
 II. FEVERS 
 
 If the heat generation goes on too rapidly, or if the 
 heat radiation goes on too slowly, as it would if the skin 
 were too dry, the temperature of the body will rise, and 
 we say the person has a fever. In the treatment of fevers 
 the physician usually tries either to decrease the heat 
 generation in the body, or to increase the heat radiation, 
 and thus reduce the temperature of the body to the 
 normal one. 
 
186 PHYSIOLOGY 
 
 9. HYGIENE OF RESPIRATION 
 I. EESPIEATOEY MOVEMENTS 
 
 The clothing of the chest aud abdomen should be loose 
 enough to enable free movements in respiration. It is 
 probable that one of the most frequent causes of ill health 
 in women is the improper oxidation of tissue as a result 
 
 (1) of shallow breathing due to improper clothing, and 
 
 (2) of living much within doors in ill-ventilated houses. 
 No one should allow a day to pass without filling the lungs 
 several times to their greatest capacity^ The advantage 
 of these deep inspirations is increased if the lungs are filled 
 with pure, out-of-door air. It is still further increased if 
 the respirations are deep as a result of vigorous exercise out 
 of doors. If one must be confined to the house for most 
 of the time, it is advisable to devote a few minutes two or 
 three times each day to vigorous calisthenics, accompanied 
 by deep breathing, preferably in front of an open window. 
 The air should always pass through the nose, as that is 
 nature's respiratory passage, and is so constructed as to 
 free the air from dust and to warm it before it goes into 
 the air passages. 
 
 II. IMPURE AIE 
 
 The principal impurity of the air in buildings is carbon 
 dioxide given off from the lungs of tlfe people in the build- 
 ing. It is also given off in large quantities by lamps and 
 gas stoves, and may be given off in small quantities from 
 coal stoves. Another impurity is the dust always found 
 in buildings. Occasionally there may be noxious gases 
 given off from furnaces, or escaping from gas fixtures or 
 from the plumbing. The latter is called sewer gas. 
 
RESPIRATION 187 
 
 The greatest care should be taken by those who have 
 buildings in charge to insure their absolute freedom from 
 all of these harmful, and sometimes fatal, impurities of 
 the air. Decaying vegetables and stagnant water in 
 cellars are frequently causes of disease, contaminating 
 especially the atmosphere of the building. No such 
 known cause of disease should be tolerated in a building. 
 
 III. VENTILATION 
 
 Ventilation is a term used to designate the change of 
 air in a building. . Every properly constructed building is 
 planned to have an air space for each occupant so large 
 that the air will not have to be rapidly changed in order 
 to be sufficiently pure. 
 
 The amount of space allowed for eq,ch person occupying 
 a schoolroom during only a few hours in a day is 250 cubic 
 feet. In a room in a dwelling used all day or all night, 
 300 cubic feet should be allowed, while in a ward in a 
 hospital it is usual to allow 1000 cubic feet for each 
 occupant. 
 
 When a room is properly ventilated, the air should 
 seem odorless to one coming in from out of doors. A 
 proper system of ventilation provides for a constant 
 change of air without noticeable drafts. An occasional 
 throwing open of doors and windows for a general rush- 
 ing in of out-of-door air, and a cooling of the air down 
 several degrees, is an exceedingly clumsy way of venti- 
 lating a room. The opening of one window of a room 
 may not permit a sufficient exchange of the air within 
 with that outside, and it is difficult at best to ventilate 
 a house through the windows alone without causing 
 drafts. 
 
188 PHYSIOLOGY 
 
 Public buildings are usually ventilated through flues 
 in the walls, flues opening near the floor and near the 
 ceiling in each room. An important feature of the ven- 
 tilation of a dwelling house is the fireplace, with its flue. 
 When the fireplace is open, as it should always be, the 
 dropping of several windows, upstairs and down, an inch 
 at the top will usually afford ample ventilation, without 
 any noticeable drafts. 
 
 The presence of illuminating gas, or other gas having a 
 distinct odor, may be at once detected ; the most danger- 
 ous gas in a building is sewer gas, which has no odor. If 
 sewer gas is present, it is usually suspected by the family 
 pliysician from the general health of the members of 
 the household, and if an expert examination reveals its 
 presence, the plumbing of the house must be repaired. 
 Fortunately, the escape of sewer gas into a house is not a 
 very frequent occurrence. 
 
 The gas that is always present, and always injurious 
 when present in an amount to exceed eight parts in ten 
 thousand, is carbon dioxide. As carbon dioxide is odor- 
 less, it is necessary to have some simple test to show when 
 it is present in excess of this proportion named above. 
 
 Keep on hand a bottle of clear limewater. To test the 
 air in any room to see if it is sufficiently free from carbon 
 dioxide to be wholesome, go into the room, provided with 
 a pint fruit jar full of water, with the bottle of limewater, 
 and with a teaspoon. Pour out the yrater from the fruit 
 jar, and its place will be taken by the air of the room. 
 Then pour into the fruit jar six teaspoonfuls of the lime- 
 water, fasten on the cover of the fruit jar tightly, and 
 shake it vigorously. If there are more than eight parts 
 in ten thousand of carbonic acid present in the room, the 
 limewater will show it by turning a milky color. If there 
 
RESPIRATION 189 
 
 is a smaller proportion than that, the limewater will not 
 be noticeably affected. 
 
 10. EXPERIMENTS 
 
 Get about a pound of unslacked lime from a mason or 
 plasterer. Put half of it into a quart fruit jar and fill the 
 jar with water. The lime will slack in the jar, and a por- 
 tion of the lime will combine with the water to make 
 calcium hydrate, or limewater. After one or two days 
 the lime will have settled to the bottom and there will be 
 clear water on top. Pour the clear portion off carefully 
 into another jar or bottle and label it : Calcium Hydrate or 
 Limewater. 
 
 1. Fill a drinking glass half full of limewater, then 
 take a glass or rubber -tube or lemonade straw and blow 
 gently through the tube into the limewater, completely 
 emptying the lungs of air, thus making the air whicli was 
 in the lungs bubble up through the limewater. Notice 
 the white cloud which gathers in the previously clear 
 limewater. 
 
 This white cloud is a precipitate of calcium carbonate 
 -which was formed by the carbon dioxide of the breath 
 combining with the calcium of the limewater. This cal- 
 cium carbonate is the same material of which your chalk 
 crayons are made, and the same mateTial of which marble 
 is composed. 
 
 2. Put a piece of candle about an inch long into an 
 empty drinking glass and light it. The flame is at first 
 fed by the oxygen in the glass, but as soon as the oxygen 
 is used up the flame dies. Take out the candle, relight 
 it, and lower it into the glass ; it will go out as soon as it 
 gets below the surface of the carbon dioxide, which now 
 
190 PHYSIOLOGY 
 
 fills the glass. Put a sheet of wet paper over the glass to 
 keep the carbon dioxide from mixing with the air. Into 
 another- glass of the same size put two tablespoonfuls of 
 limewater. Invert the glass containing the carbon dioxide 
 over the glass containing the limewatei'; draw out the 
 sheet of paper from between the glasses, and vigorously 
 shake the two glasses, liolding them together at the rim. 
 The carbon dioxide has mixed with the limewater and 
 formed the turbid cloud of calcium carbonate. 
 
 From these two experiments we find, first, that by the 
 oxidation of a candle, as well as by the oxidation of the 
 tissues of the body, carbon dioxide is formed. Second, 
 we find that the flame of a candle will be extinguished in 
 an atmosphere of carbon dioxide. It is also true that the 
 "flame of life" will be extinguished in a similar atmos- 
 phere. 
 
 3. Test the air in your schoolroom with a fruit jar as 
 directed above in the text, to see if the ventilation is 
 sufficient. If it is not sufficient, try to devise some means 
 by which the ventilation can be improved without causing 
 direct drafts upon the occupants of the room. 
 
 PROBLEMS 
 
 1. How many pupils should be seated in a schoolroom 
 30 feet wide, 40 feet long, and 15 feet high ? 
 
 2. If a schoolroom is 20 feet wide and 30 feet long, 
 how high should the ceiling be to accommodate 30 
 pupils ? 
 
 3. How many individuals may occupy a sleeping room 
 10 by 15 feet, 8 feet high? 
 
 4. How high should a hospital ward be which is 20 
 feet wide, 40 feet long, to accommodate 10 patients ? 
 
RESPIRATION 191 
 
 11. THE EFFECTS OF NARCOTICS UPON RESPIRATION 
 
 I. EFFECTS OF ALCOHOL UPON TQE KED BLOOD COK- 
 
 PTJSCLES 
 
 Alcohol acts upon the red blood corpuscles, lessening 
 their power to take oxygen from the air cells of the lungs 
 and carry it to the tissues of the body.^ 
 
 The direct effect of the above upon the tissues is, 
 according to Dr. Parker of Chicago, the diminishing of 
 the functional activity of the secreting and excreting 
 structures, causing the blood to accumulate and retain 
 the waste material. 
 
 IT. RELATION OF ALCOHOL TO ANIMAL HEAT 
 
 Dr. Bodlander proved several years ago that about ninety 
 per cent of alcohol taken into the stomach is oxidized, 
 forming carbon dioxide gas and water, and generating 
 heat. He believed that the injury done by alcohol con- 
 sists in part of the robbing of the other cells of the body 
 of their supply of oxygen, and the rapid formation of 
 carbon dioxide, which acts as a poison until thi'own out 
 of the system. 
 
 " For the heating of the body it sefems that only certain 
 kinds of carbonaceous substances are suitable. The action 
 of alcohol upon the cells tends to cause their degeneration, 
 changing them to fat, and, as it were, makes the cells of 
 the various organs grow prematurely old. Alcohol is, 
 it seems, a most unsuitable substance with which to pro- 
 duce warmth."^ 
 
 1 AUbutt's System of Medicine, Vol. Ill, p. 839, 
 
 ' Medical Pioneer, October, 1896, p. 204, quoting from Pfluger's Archives, 
 Vol. XXXU, p. 399. 
 
192 PHYSIOLOGY 
 
 Men who use ardent spirits often say that they do so 
 in winter to "keep their bodies warm." No one could 
 make a greater mistake than to suppose that the effect of 
 alcoholic drinks is to warm the body. Many and often 
 repeated experiments upon this question prove that when 
 the liquor is taken in sufficient quantity to make the 
 person feel warm he is really losing body heat through 
 the skin, and the temperature of the body is falling. If a 
 person is exposed to extreme cold for several hours, the 
 temperature of the body may fall so low as to endanger 
 life.i 
 
 We learn from this that the body is not always warm 
 when it feels warm. In the case above mentioned the 
 person feels warm because the skin is kept warm by the 
 blood flowing to it in unusual amounts. 
 
 III. RELATION OF ALCOHOL TO LUNG DISEASES 
 
 A recent article in the Medical Times, quoting from 
 the Hospital Crazette, states that the use of alcohol makes 
 a person more liable to pneumonia. 
 
 Dr. Delearde says that pneumonia is much more severe 
 in those addicted to the use of alcoholic drinks than in 
 others; that it runs a longer course; that it is often ac- 
 companied by violent delirium, followed by prostration, 
 
 1 Professor Brunton, St. Bartholomew HospitaJ^ London. Lectures on the 
 Action of Medicine, p. 128. ' ' A party of engineers were surveying in the 
 Sierra Nevadas. They camped at a great height^ above the sea level, where 
 the air was very cold and they were chilled and uncomfortable. Some of them 
 drank a little whisky and felt less uncomfortable ; some of them drank a lot 
 of whisky and went to bed feeling very jolly and comfortable indeed. But in 
 the morning the men who had not taken any whisky got up in good condition ; 
 those who had taken a little whisky got up feeling very miserable ; the men 
 who had taken a lot of whisky did not get up at all ; they were simply frozen 
 to death. They had warmed the surface of their bodies at the expense of their 
 internal organs." 
 
RESPIRATION 193 
 
 or even unconsciousness, and that in those who recover at 
 all, there frequently occur abscesses in the liver or in other 
 organs. 
 
 Dr. Legendre, a Paris physician, has recently published, 
 for public distribution, a leaflet in whijch he says : " ^ilco- 
 hol is a frequent cause of consumption by its power of 
 weakening the lungs. Every year we see patients who 
 attend the hospital for alcoholism come back after a 
 period to be treated for consumption." i 
 
 An American medical writer ^ points out the reason whj' 
 the use of alcohol makes one liable to consumption. He 
 mentions the use of alcohol among various other things 
 which cause the natural vital resistance of the healthy 
 body to be impaired. Among those other things men- 
 tioned with alcohol, which produce this impairment of 
 vital resistance, are : " Living in overcrowded, ill-ven- 
 tilated houses, on damp soils, or insufScient clothing and 
 outdoor exercise." 
 
 IV. INFLUENCE OP TOBACCO UPON THE KESPIRATOEY 
 
 SYSTEM 
 
 " Nicotine stimulates secretion in general, as is illus- 
 trated by its influence upon the mucous glands of the 
 mouth. This overstimulation of the mucous membrane 
 would naturally lead to the development of catarrhal 
 affections."^ 
 
 REVIEW OF THE RESPIRATION 
 
 1. Every living thing, both plant and animal, needs oxygen. The 
 process of furnishing oxygen for the tissues of a plant or animal is 
 called respiration. 
 
 1 London Lancet. 
 
 2 See Journal of American Medical Association, October 23, 1897, p. S47. 
 8 Dr. J. W. Seaver, Yale University, In Journal of Inebriety. 
 
194 PHYSIOLOGY 
 
 2. The Inspiration and Expiration of air t*o and from the lungs are 
 together called External Respiration; while the exchange of oxygen 
 for carbon dioxide in the tissues is called Internal Respiration. 
 
 'i. The A ir passages are : the nasal passage, the pharynx, the larynx, 
 the windpipe, the bronchi, the bronchioles, and the air cells. 
 
 i. The Air passages, below the larynx, are lined tvith ciliated cells. 
 The cilia can'y the mucus and particles of dust that may enter the 
 lungs with the air up to the larynx, where it gives one a tickling sensa- 
 tion and is coughed up. 
 
 5. The Diaphragm is the principal muscle of respiration. Thein^er- 
 costal muscles and'the abdominal muscles assist. 
 
 6. The movements of the chest and abdomen should not be interfered 
 with by clothing that fits too tightly. 
 
 7. Describe : Coughing, sneezing, yawning, hiccoughing, sighing, 
 crying, laughing, and sobbing. 
 
 8. How many vowels has the English language? How are these 
 vowel sounds produced and how modified? How many consonant 
 soands in English? How are consonants classified and how are they 
 produced? 
 
 9. ^^'hat are the characteristics of a cultured and refined voice? 
 All people may cultivate refinement in the voice. One is judged more 
 by the voice and the language than by anything else when he first 
 meets a stranger. First impressions are very valuable when favorable, 
 and very damaging and difficult to remove when unfavorable. 
 
 10. The air is composed chiefly of Nitrogen and Oxygen, with a 
 little Carbon dioxide gas and Water vapor. 
 
 .11. In the lungs the &\x gives up about one fourth of its oxygen, receives 
 carbon dioxide in almost an equal quantity, .and receives water vapor, 
 and also a small amount of organic matter. 
 
 12. Oxygen is carried by the red blood cells, while carbon dioxide is 
 carried mostly by the plasma. 
 
 13. The heat of the body is produced by the oxidation of its tissues. 
 
 14. The heat of the body is regulated partly by changes in the rate of 
 oxidation and partly by changes in the rate of the giving up of heat 
 by the skin. In a similar way one changes the temperature of a 
 house by changing the rate at which the fire in the furnace burns, or 
 by opening or closing windows. Both of these methods of regulating 
 may be changed at the same time. 
 
 15. One should often breathe deeply to expand and develop the 
 
RESPIRATION 195 
 
 lungs. One should breathe pure air either out of doors or in well- 
 ventilated rooms. 
 
 16. Alcohol, though oxidized in the body, lowers the temperature, be- 
 cause more heat is lost from the skin than is produced by the oxidar 
 tion of the alcohol. Explain this. 
 
 17. The use of alcohol weakens the lungs and makes one more liable to 
 lung diseases than he would be if he abstained ffom it. 
 
 18. The use of tobacco is likely to cause of to increase the tendency 
 to catarrh. 
 
CIIAP'JEK VIII, — HOW TJfE FOOD IS ( SKD IN 
 ■JIIJ-: BODY 
 
 TifE chapter on nutrition d<;,scribed foodn, and told how 
 they were digested in the alimentary eanal, hut did not 
 tell how the foodts were used hy the body after they were 
 digested . 
 
 The object of thi« cliapter is to show first, liow the 
 digested food is al)sorbed from the al.irnentary canal; and 
 seeond, how it is built up into living tissue in the body ; 
 and third, under wliat conditions it is oxidized, and what 
 is formed as a result of the oxidation. Before beginning 
 these snhjeets, let us review the chapter on nutrition by 
 answering the following questions : -^ 
 
 1. How many and what kinds of food are tliere, or how 
 many kinds of food stuff's''' 
 
 2. A\'hat is the name of the digestiye fluid secreted into 
 the mouth? 
 
 '^j. On what class of foods does this fluid act, and wliat 
 changes does it produce '' 
 
 4. What digestive fluid is secreted into the stomach? 
 
 o. On what kind of food does it act ? 
 
 0. What change does it produce upon this food ? 
 
 7. What digestive fluids are secreted into the small 
 intestine ? 
 
 8. Wliat kinds of food are digested in the small intes- 
 tine ? 
 
 9. What name is given to the partly digested food tliat 
 passes through the stomach into the s/nall intestine ? 
 
HOW THE FOOD IS USED IN THE BODY 197 
 
 10. To what form are all the starches and sugars finally 
 reduced by the digestive process ? 
 
 11. To what form are all proteid foods reduced by the 
 digestive process ? 
 
 12. To what forms are the fats reduced by the digestive 
 process ? 
 
 1. HOW THE DIGESTED FOOD IS ABSORBED FROM 
 THE ALIMENTARY CANAL 
 
 After the digestive process has changed the starches 
 and sugars to dextrose, the proteids to peptones, and the 
 fats to soap and emulsion, the food is still no part of the 
 body. It is inside of the body, but in a closed tube, and 
 until it gets through the walls of the tube it is not part 
 of the body. 
 
 I'he interior lining of the intestines is thrown up in folds 
 which, when magnified, look like fingers projecting into 
 the intestines (Fig. 44). These are the villi which absorb 
 the food into the system. If we magnify the villus very 
 much, wc see the whole surface is covered with absorb- 
 ing cells. They are not open, but the chyme, or digested 
 food, passes through the thin cell wall's. If we cut a thin 
 slice across the villus (Fig- -15), we see the absorbing cells 
 leading toward the interior, where tliere are many blood 
 vessels, and beyond which, in the very center of the 
 villus, is a tube called a lacteal, which you know is an 
 intestinal lymphatic. 
 
 Some of the nourishment absorbed by the cell is taken 
 up by the blood vessels, and some goes into the lacteal 
 which carries it to a large duct, called the thoracic duct, 
 which goes up the left side of the center of the body to 
 the neck, where it empties into the jugular vein (Fig. 38, 
 
198 
 
 PHYSIOLOGY 
 
 p. 150). The lacteals take up the fats and part of the 
 
 peptones. 
 
 The rest of the nourishment, the sugars and a part of 
 
 the peptones, is taken up by the blood vessels which unite 
 
 to form the portal vein, 
 and is carried by the 
 blood to the liver. 
 
 Wlien the foods are 
 passing through the 
 absorbing cells of the 
 villus, a change is 
 made in some of them 
 by the absorbing cells. 
 The peptone absorbed 
 from the alimentary 
 canal is sent into the 
 blood vessels, not as 
 peptone, but as blood 
 albumen, in which form 
 it accumulates until it 
 is taken up from the 
 capillaries by the hv- 
 ing tissues. The fats 
 are taken up from the 
 alimentary canal by 
 the absorbing cells, 
 and turned into the 
 lacteals in minute glob- 
 These globules 
 floating in the lymph 
 
 plasma give it the milky appearance. The sugar absorbed 
 
 is turned into the blood vessels unchanged, and so passes 
 
 to the liver as sugar. 
 
 F _ _ ^6 pro- 
 
 jections of the mucous membrane of the 
 small intestine. In the third one from the 
 right and second from left notice the central 
 lacteal (i) . The intestinal glands ate shown 
 at {h). The heavy hlack lines are blood ules 
 vessels. [Fiersol.] 
 
HOW THE FOOD IS USED IN THE BODY 
 
 199 
 
 2. HOW DIGESTED FOOD IS BUILT UP INTO LIVING 
 TISSUE IN THE BODY 
 
 In the previous lesson we traced the absorbed food 
 stuffs directly into the blood of the portal vein or indi- 
 rectly into the veins by way of the lacteals and the 
 thoracic duct, so that the absorbed fbod at once becomes 
 
 Fw. 45. — Showing a cross slice of a villus. Note the central lacteal (e.Z.), 
 the blood capillaries (c), the absorbing cells all around the villus, the 
 mucus-forming cells at (^r). [Sehaefer.] 
 
 a part of the circulating fluids of the body ; but it does 
 not become living tissue until it is absorbed into the liv- 
 ing cells of the tissue. 
 
 Let us first trace the dextrose. Sboner or later all the 
 dextrose absorbed circulates through the liver. Figure 
 46 shows the general shape of the liver as it looks from 
 below. You will notice that the portad vein divided, send- 
 ing a branch to each lobe of the liver. Notice the liver 
 artery which brings oxygenated blood from the lungs, so 
 that there are two streams of blood passing to the liver, 
 one from the intestines, and one from the lungs, while 
 hall's phys. — 13 
 
200 
 
 PHYSIOLOGY 
 
 there is one stream of blood going away from the liver by 
 way of the vena cava. 
 
 The gall bladder serves as a reservoir to collect a por- 
 tion of the bile which is from time to time sent out through 
 the bile duct into the intestines. Now if a very thin 
 slice were made through the liver, and this slice examined 
 under a high power microscope, one would find it divided 
 
 Fig. 46. — Under surface of the liver. [Tracy.] 
 
 five-sided or six-sided ar«as called lobules 
 
 into little 
 (Fig. 47). 
 
 The blood of the portal vein passes through a network 
 of veins marked p in the figure, forhiing a network of 
 venules between the lobules. From this network of 
 venules, innumerable fine capillaries pass toward the 
 center of each lobule, gathering there into a venous trunk. 
 
HOW THE FOOD IS USED IN, THE BODY 
 
 201 
 
 which passes out of the lobule and joins others on the 
 way to the vena cava. 
 
 While the blood is passing through the capillaries, an 
 opportunity is given for the active gland cells of the 
 liver (which are shown in two places in the lobules only, 
 though really they fill all the space) to absorb the dextrose 
 from the blood. What these cells do with the dextrose 
 
 Fio. i7. — Diagram of two liver lobules. Note the branches of the portal rein 
 (marked p), from which a system of capillaries pass in to the middle of the 
 lobules. In the lobule at tlie right is shown how the blood gets out of 
 the lobule and joins a branch of the liver vein on its way to the vena cava. 
 Note the liver cells between the capillaries. The liver cells do the work of 
 the liver. [Landois.] 
 
 is one of the most wonderful processes ; they change it back 
 to starch, so that food that was taken in the iorm of starch 
 is changed to sugar, and then back to starch in the body. 
 This liver starch is called animal starch. 
 
 The liver acts as a storehouse fqr this kind of food, so 
 that after a meal where considerable starch or sugar has 
 been eaten, the liver will be filled with starch, which is 
 thus stored away to be given out a little at a time until 
 
202 PHYSIOLOGY 
 
 the next meal. When this food is needed by the system, 
 which will probably occur within Wo hours after it is 
 stored in the liver, the liver changes the starch back to 
 sugar, and the liver cells throw this sugar out into the 
 capillaries again, and from the capillaries it passes into 
 the liver vein, and from the liver vein into the vena cava, 
 which carries it to the right side of the heart, whence it 
 goes to the lungs, and is sent to the left ventricle. The 
 left ventricle sends it through the arterial system to the 
 tissues, where, as a part of the plasma, it oozes through the 
 capillaries and around the cells of the tissues. 
 
 Now these cells use more sugar than anything else. 
 All the living cells of our body use sugar ; so the sugar is 
 absorbed from the plasma and taken into the living cells, 
 where it becomes a part of their protoplasm, that is, it is 
 assimilated, but here it is soon oxidized to generate the 
 energy which the cells must use in their work. 
 
 The fat which was thrown into ttie venous system in 
 the form of minute globules, floats along in the veins into 
 the heart, through the lungs, and then by the way of the 
 ventricle into the arteries and capillaries, where it comes 
 in contact with the living cells of the various tissues. 
 It is taken up from the plasma by these cells and either 
 built into living protoplasm or oxidized within the proto- 
 plasm to yield energy, or it may be deposited within the 
 protoplasm in the form of fat globules. 
 
 If one eats more starch and fats tlian are required for 
 the energy of heat and motion, this material is usually 
 deposited in the savings bank of the system, because the 
 system is very economical, never wasting any food that it 
 has taken the trouble to digest. The savings bank of the 
 system is located in the connective tissue, and the sav- 
 ings are deposited in the form of fat. If there is much 
 
HOW THE FOOD IS USED IN THE BODY 203 
 
 saved, the individual may become quite "fleshy," as we 
 say. 
 
 The proteid matter absorbed as peptone and changed to 
 blood proteid, continues to accumulate in the blood until 
 it is absorbed by the living cells and either built up into 
 living protoplasm or oxidized within the cell protoplasm 
 to yield energy. 
 
 Remember : (1) Food taken into the alimentary canal 
 must usually be digested before it is absorbed. Such sub- 
 stances as water, salt, and certain kinds of sugar do not 
 need digestion, but are absorbed in the form in which 
 they are eaten. (2) Absorption is the taking up of sub- 
 stances by the body ; for example, oil may be absorbed 
 by the skin, oxygen by the lungs, ami sugar, fats, water, 
 peptones, salts, etc., by the lining of the intestine. (3) As- 
 similation is building up of absorbed food into the living 
 tissue of the body. (4) Foods do not yield their energy 
 to the body until they are oxidized. Oxidation is the 
 reverse of assimilation. Assimilation is a building-up 
 process, while oxidation is a pulling-down process. As- 
 similation requires energy to bring it about, while oxida- 
 tion yields energy. Motion, heat, and light are kinds of 
 energy. 
 
 3. THE GENERATION OF HFE ENERGY 
 
 The first lesson in nutrition tells why we eat. You 
 remember that we eat food for the energy that it contains, 
 and the whole processes of digestion, and circulation, and 
 respiration all lead up to the generation of this energy, to 
 obtain which the food was taken. We traced the food, 
 which is the fuel of the body, into the living cells ; we 
 have traced the oxygen into the living cells. The next 
 
204 PHYSIOLOGY 
 
 step is the oxidation of this body fuel and the generation 
 of life energy. 
 
 Muscle tissues are by far the larger part of the active 
 tissues, so that we are prepared to expect that most of the 
 energy liberated by the body will be muscular energy. 
 One usually thinks of muscular energy as energy of 
 motion, because we use our muscles in our movements; 
 but the energy of motion is not more important than the 
 heat energy which the muscles generate. The muscles 
 generate motion during only a small part of the time, but 
 they generate the energy of heat continually, never stop- 
 ping from the day of birth to the day of death, nor any 
 single hour between these days. 
 
 The glands of the body work only a part of the time, 
 and some of the work which the glands do generates heat, 
 while other parts of their work require energy from other 
 sources. 
 
 The nervous system generates a kind of energy peculiar 
 to itself, which seems to be similar in many respects to 
 electricity. There is some heat, also, generated in the 
 nervous system. 
 
 Where fuel is being oxidized, or burned, we usually find 
 smoke, ashes, and gases. The smoke is composed of 
 unburned carbon and water ; the ashes represent the 
 mineral matter of the fuel ; while the gases are repre- 
 sented, for the most part, by carbon dioxide. The 
 oxidation in the body is similar to the oxidation in a 
 locomotive in many respects, and there are waste matters 
 resulting from body oxidation, as there ai'e waste matters 
 resulting from fuel oxidation. Water is formed; carbon 
 dioxide is formed ; and there are cert,ain substances which 
 may represent the ashes, substances which contain nitro- 
 gen. These -substances are as poisonous to the flame of 
 
HOW THE i'OOD IS USED IN THE BODY 205 
 
 life, if they are allowed to collect in the body, as the 
 carbon dioxide which collects in the di-inking glass is 
 poisonous to the candle flame. 
 
 If the unoxidized nitrogenous substances are not thrown 
 out of the system, they will clog it* up and destroy its 
 proper action, just as surely as the cinders and ashes of 
 the locomotive would put out the fire if they were not 
 raked out. 
 
CHAPTER IX.— HOW THE WASTE MATERIALS 
 ARE THROWN OUT OF THE BODY 
 
 l:s the previous lesson we learned that active cells 
 are constantly forming products of oxidation which are 
 poisonous to the system, and which, if not thrown out, 
 would very soon destroy the life. These products can 
 be grouped into three classes : (1) carbon dioxide ; (2) 
 water; (3) nitrogenous substances and mineral salts. 
 
 The carbon dioxide is carried to the lungs by the blood, 
 and thrown out of the system in the way described under 
 Respiration. The water that is formed in the system, to- 
 gether with large portions of that which is taken in as drink, 
 is given off from the system in two different ways, besides 
 that which leaves by way of the lungs and intestines. 
 First, it is given off by the skin in the form of perspira- 
 tion. There are innumerable fine pores, those lining the 
 palm of the hand being large enough to be seen with a 
 common magnifying glass. These pores, which cover the 
 whole surface of the body, are the openings of minute 
 glands which lie in the skin, and who.se work it is to form 
 the sweat or perspiration. These glands are called the 
 sweat glands. 
 
 When we were studying about animal heat, we found 
 that the temperature of the body was controlled in part 
 by the rate at which water was poured out on the skin in 
 the form of perspiration. The work which these sweat 
 glands do in helping to regulate temperature is very 
 much more important than the work; which they do in 
 
 206 
 
H0A7 THE WASTE MATERIALS ARE THROWN OUT 207 
 
 throwing out the water of the system, because the water 
 can go out of the lungs, intestines, and kidneys, but there 
 is no tissue or organ that can, in man, take the place of 
 the skin in the regulation of the temperature. 
 
 Let us, then, remember that of two kinds of work which 
 the skin does, the heat-regulation part is very much more 
 important than the work which it does in ridding the 
 system of a part of the water. 
 
 But the most important organs for throwing out waste 
 materials are the kidneys. 
 
 1. EXCRETION BY THE KIDNEYS 
 
 The process of throwing out waste material from the 
 body is called excretion. We have seen, from what has 
 just been said, that the lungs, and skjn, and intestines are 
 all organs of excretion, or excretory organs. The kidneys 
 differ from other excretory organs i*n the fact that they 
 have no other function, but devote their whole time and 
 energy to the work of separating out from the blood 
 waste substances which, if retained in the body, would 
 soon cause convulsions and death. 
 
 The kidneys are two in number, and about long enough 
 to reach across the palm of the hand. They are located 
 in the back part of the abdominal cavity, back of the thin 
 membrane which lines the cavity, and which holds them 
 in place. They are located about opposite the small of 
 the back, one on either side of the spinal column. Each 
 receives a large branch from the abdominal aorta, and 
 each gives off a large branch which passes to the inferior 
 vena cava (Fig. 48). From each kidney a tube passes 
 down to the bladder, which is located in the lower part of 
 the abdominal cavity, in front. 
 
208 
 
 PHYSIOLOGY 
 
 The kidney is a glandular organ, and the arterial blood, 
 after passing into the kidney, is distributed in fine arteri- 
 oles to an innumerable num- 
 ber of little capillary tufts, 
 where the excess of water 
 of the blood is filtered out, 
 and passes along a little 
 glandular tube, which is 
 surrounded by a network of 
 capillaries. The cells of 
 this glandular tube take 
 out from the blood in the 
 capillaries all of the nitro- 
 genous waste matter and 
 pour it into the canal of 
 the tube, where it is washed 
 along by the water into a 
 common receptacle in that 
 part of the kidneys where 
 the blood vessels enter, and 
 from this common receptacle 
 
 Fig. 48. — The kidneys and bladder as . a ^ ii Ti_i_i 
 
 they would look If viewed from it nows dOwn the little 
 
 behind, a, kidneys; 6, abdominal drainage tube to the blad- 
 
 aorta; e, vena cava; d, ureters, ° . 
 
 tubestocarry urine to the bladder; der, where it collects, and 
 e, bladder, from whicli it is from time 
 
 to time given off. 
 
 2. THE HYGIENE OF THE LIVEp,. AND KIDNEYS 
 T. HOW TO TAKE CARE OF THE LIVEE 
 
 It is not easy for a person to tell |,he condition of his 
 liver. One of the functions of the ^ver is to form bile. 
 When the liver is in a condition to form bile properly, it 
 
HOW THE WASTE MATERIALS ARE THROWN OUT 209 
 
 is usually in a condition to do the rest of its work, 
 When the bile is improperly formed, or formed in too 
 small quantities, a person becomes constipated, and that 
 which passes the bowels is too light in color. To guard 
 against this condition, which is a very serious one, and 
 which always leads to the derangement of other functions 
 of the body, one should avoid ovejeating and should 
 take plenty of exercise in the open air. If, through care- 
 lessness, the system gets in the condition above mentioned, 
 one should consult a physician for more extended advice 
 than can be given in this brief book. 
 
 II. HOW TO TAKE CARE OF THE KIDNEYS 
 
 The urine should be a light yellow color, and perfectly 
 clear, and no sediment should collect if it stands in a 
 receptacle for twenty-four hours. The kidneys are in- 
 jured by overwork ; and, as the principal work of the 
 kidneys is to excrete nitrogenous waste matter, it is easy to 
 see that the eating of too much nitrogenous food, or pro- 
 teid food, will result in the kidneys being overworked. 
 
 The best rule to follow, if one wishes to keep these 
 organs in healthy condition, is to eat sparingly of meat, 
 and drink plenty of water. Most people drink too little 
 water ; few people drink too much water. 
 
 If the urine becomes unusually dark in color, or if there 
 should be a reddish sediment when it stands in a recep- 
 tacle, one should drink all the water he can for a few 
 days. Lemonade is wholesome for these organs which 
 eliminate the waste materials from the body. The lemon- 
 ade should be taken with little sugar, and not too strong, 
 and may be taken in large quantities, especially in 
 summer. 
 
210 PHYSIOLOGY 
 
 in. THE EFFECTS OF ALCOHOL UPON THE LIVBB AND 
 KIDNEYS 
 
 Dr. Wilkins ^ says that the coloring matter of the bile 
 cannot be properly oxidized in the presence of alcohol, 
 and that the work of the liver must be deranged while 
 alcohol is passing into the system through that organ. 
 
 Dr. McMichael^ says, "Alcohol produces disease of 
 the liver and of the kidneys because these glands are most 
 concerned in the throwing out of any poison, and are 
 always, until they are deranged in structure, engaged in 
 removing it from the body." He says that the disease 
 almost universally caused in the liver by alcohol, is one 
 in which the connective tissue framework of the liver in- 
 creases, taking the place of the liver cells, until the liver 
 is no longer able to perform its function. 
 
 The kidneys may undergo a change similar to that of 
 the liver when alcohol is used, even in moderate amounts, 
 for a long period. 
 
 Such profound changes in organs whose work is so 
 important to the system, are naturally accompanied by 
 derangements of the general health, and at last are fre- 
 quent causes of death. 
 
 1 New York Medical Journal, Septeipber 22, 1894. 
 
 2 Dietetic and Hygienic Gazette, May, 1897, p. 279. 
 
CHAPTER X. — THE SKIN — HOW IT IS MADE, 
 AND WHAT IT DOES — HOW TO TAKE CARE 
 OF IT 
 
 The skin has been mentioned several times in the pre- 
 ceding lessons. We have found that it is a most impor- 
 tant organ for the regulation of the temperature, and that 
 it takes a part in the throwing out of waste materials 
 from the body ; but its most important work has not yet 
 been mentioned. You remember that the little plant, 
 described in the first lessons of this book, was provided 
 with a thin, transparent skin; you remember that the 
 bark of a tree was called its skin, and you know that 
 the bark of a tree protects from injury the sensitive 
 tissues which lie beneath it. 
 
 In a similar way, the skin of animals is an organ of pro- 
 tection ; and although this organ may perform, or assist in 
 performing, several other functions, this one is the most 
 important of all. The skin is made in such a way as to 
 adapt it especially for its principal function, protection. 
 
 1. now THE SKIN IS MADE 
 
 The skin is composed of two layers ; one of these is 
 composed of living tissues, and the other of nonliving tis- 
 sues. Figure 49 shows the living layer of skin at Dm. 
 This layer, which is called the dermis, or true skin, is 
 composed of a network of fibers* of connective tissue, 
 within which lie the blood vessels, and lymphatics, which 
 
 211 
 
212 
 
 PHYSIOLOGY 
 
 bring the nourishment to the tissues ; the nerves, which 
 make tlie skin sensitive to touch and to changes of temper- 
 ature ; the oil glands, which pour their oil out on the sur- 
 
 
 ■Dm 
 
 Sb 
 
 Fig. 49. — Vertical section o( the skin, magnified; a, scarfskin ; 6, pigment 
 cells; o, papillse; 2)m, true skin ; e,/, fat cells; jr, sweat glands ; /i, outlets 
 ■ of sweat glands : i, their openings on the surface of the skin ; k, hair follicle ; 
 t, hairs projecting from the skin ; m, hair papilla ; n, hair bulb ; o, root of 
 hair ; p, openings of oil glands ; Ep, epidermis ; Sb, subcutaneous connectiTe 
 tissue. 
 
 face of the skin ; the hair follicles and the ducts of the sweat 
 glands. 
 
 This living part of the skin is vpry elastic, adapting 
 itself perfectly to the curves of the body and the bending 
 of the joints. Notice in the figure that the hairs have 
 their roots in this true skin. Each hair grows from a 
 papilla (Fig. 49, ot) ; this papilla is provided with a nerve 
 
THE SKIN 213 
 
 fiber and a tuft of capillaries. From the surface of this 
 papilla the hair grows, thus pushing the hair out of the 
 follicle, so that the hair becomes longer and longer as it 
 grows at the papilla. 
 
 The oil glands are located on either side of the hair 
 follicle, and pour their secretion into the follicles beside 
 the hair. This passes along through the epidermis, and 
 pours out upon its surface around the hair. Notice that 
 the surface of the true skin is rough, the prominences 
 reminding one of a mountain range. These prominences 
 are called papillse. Within every papilla there are either 
 nerve endings or tufts of capillaries. The nerve endings 
 make the surface of the skin sensitive, and the capillaries, 
 besides bringing nourishment, bring the blood very near 
 to the surface, where it may be cooled or where it may 
 warm the surface. 
 
 The papillse of the true skin are not exposed to the 
 air, but are covered with a deep protective layer, called 
 the cuticle, or the epidermis. The cuticle is formed by 
 the true skin ; the cells of the cuticle which lie next to the 
 true skin are living cells. They draw their nourishment 
 from the true skin, and keep dividing and forming new 
 cells. These new cells are pushed out from the true 
 skin until they get so far from the blood and lymph of 
 the true skin that they can no longer get nourishment, 
 and so they die. The dark line between a and b in the 
 figure shows where this change takes place. 
 
 That portion of the cuticle that is darker in the figure 
 represents the dead scarfskin. Now as these cells are 
 constantly forming on the surface of the true skin, the 
 scarfskin would become enormously thick if its surface 
 layers were not rubbed off by friction, such as that of the 
 clothing. The cuticle is the protective tissue of the 
 
214 PHYSIOLOGY 
 
 whole body ; the dead cells of its surface are not sen- 
 sitive. Pressure upon its surface is felt because it 
 presses through the epidermis upon the sensitive papillae 
 beneath. 
 
 The cuticle alone is not sufficient protection for the 
 body, so most surfaces of the bodies of the mammals are 
 provided with hair. Notice the back of your arm, and 
 you -will see great numbers of fine hairs growing ; these 
 hairs protect the surface of the skin. They are especially 
 thick upon the head, and when man lived in a savage 
 state the matted hair was usually the only protection for 
 the head. 
 
 The tips oE the fingers and toes are protected with nails. 
 The papilla through which the hair grows corresponds to 
 a papilla at the surface of the true skin, and a hair which 
 grows from the surface of the hair papilla corresponds to 
 the cuticle growing from the surface of the papilla of the 
 true skin, so that we can see that the hair is modified 
 cuticle. In a similar way the nails represent modified 
 cuticle, and grow from the surface of the modified papillae. 
 The teeth grow from modified papillae, and also represent 
 modified cuticle. The same thing is true of the feathers 
 of birds, the scales of fishes and reptiles, and the hoofs, 
 horns, and claws of the lower mammals. If you think of 
 the use to which these animals put these structures, you 
 will see that they are all used for protection except the 
 teeth, which, although used somewhat for defense, may 
 also be used for other purposes. 
 
 The work of the skin is first of all protection. In most 
 mammals the protection against extreme changes of tem- 
 perature is provided for by a thick coat of hair or fur. 
 In birds the coat of feathers performs a similar service. 
 At first it may seem that the horse's coat could not be 
 
THE SKIN 
 
 215 
 
 quickly changed from a thin one to a thick one, but that 
 he must wait for the spring shedding of his thick winter 
 coat in order to have a summer coat, which is thickened 
 up by a new growth of hair in the fall for winter; but the 
 horse may change the thickness of his coat in a few min- 
 utes. If you will look at the hairs on the back of your 
 arm you will see that they do not come straight out of the 
 skin, but they come out obliquely, and all that are near 
 together lie in the same direction. Each hair has a little 
 muscle attached to the end of its follicle, as shown in 
 
 Fig. 50. — Diagram showing at A the hairs lying down and the muscles at 
 rest. At B the muscles have contracted, puUiug the hairs up straight, thus 
 making the coat much thicker and warmer. 
 
 Figure 50. When the skin is warm, the hair lies down as 
 shown in position A, that makes the whole coat of hair 
 compact. When the cold strikes the skin, the muscle of 
 each hair contracts and draws it up So that it stands per- 
 pendicular to the skin. This makes the coat of hair very 
 much thicker than it was before and keeps the animal 
 correspondingly warmer. In man the hair which covers 
 the general surface of the body is so thin and short that it 
 cannot keep the body warm, but the muscles contract just 
 the same and pull the hairs up, pushing up a little point 
 hall's phys. — 14 
 
216 PHYSIOLOGY 
 
 of skin about each hair. This appearance of the skin is 
 called goose flesh. 
 
 The cuticle protects the delicate .dermis from friction 
 and pressure. If the friction and pressure are severe, the 
 cuticle becomes thicker and more dense than it is over 
 the general surface of the body. Look at the palms of 
 your hands and see if you have not little calluses. The 
 cuticle on the bottom of the foot is much thicker than 
 on the top of the foot. If the shoe does not fit perfectly, 
 a thickened callus may form where it presses or rubs the 
 foot. If this thickened callus becomes hard it may make 
 the dermis beneath sensitive and sore. We call this 
 condition a corn. 
 
 Next to the function of protection, the most important 
 work of the skin is the regulation of temperature mentioned 
 above, and next is the part which the nerves of the skin, 
 together with modified portions of the skin, play in warn- 
 ing the system of danger or of changes. This function 
 of the nerves of the skin is called Sensation. Another 
 but comparatively unimportant function of the skin is 
 excretion. 
 
 2. THE HYGIENE OF T^E SKIN 
 
 I. CLEANLINESS 
 
 The oil which is poured out upon the surface of the skin 
 is perfectly clean, but it very readily collects dust and 
 other impurities of the air. The scarfskin is continually 
 being shed in minute scales composed of a few thin cells. 
 If these were not removed from the surface they would 
 soon collect in sufficient quantities to be visible as minute 
 scales. The most important source of uncleanness of the 
 skin is the perspiration which is constantly being poured 
 out upon the surface of the skin. 
 
THE SKIN 217 
 
 Figure 49 shows the little coiled sweat gland in the loose 
 tissue below the true skin. This siyeat gland takes up 
 water and various other substances from the blood, and 
 pours them out upon the surface of the skin. 
 
 Sometimes we are not conscious of the perspiration 
 because it does not make the surface wet, that is, because 
 it escapes in the form of vapor from the pores ; that kind 
 is called insensible perspiration, but when it comes in largo 
 enough quantities to be condensed, and make the skin 
 moist, then we call it sensible perspiration. The water of 
 the perspiration evaporates to cool the body, but the salt 
 and other solids remain upon the surface of the skin. 
 This, mixed with the oil, the little scales of scarfskin, and 
 the dust collected from the atmosphere, will in a very 
 short time make the surface of the body unclean. 
 
 A general bath, in which use is made of soft water and 
 soap, followed by thorough rubbing with a coarse towel, 
 is a most efficient method for insuring the cleanliness of 
 the skin. For persons in the ordinary occupations a 
 general bath such as that described is not necessary of tener 
 than once or twice a week ; if soap is used oftener, it is 
 likely to make the skin dry and rough ; if a warm bath is 
 taken oftener, it is likely to relax the skin and make the 
 person take cold easily. A general rule for the use of 
 soap and water for cleansing the body is : use it just as 
 freely and just as frequently as is necessary to keep the 
 body clean ; the hands may need it several times a day ; 
 other portions of the body may not need it oftener than 
 once a week. 
 
 II. THE MORNING BATH 
 
 The warm water cleansing bath, because of its relaxing 
 effect, may best be taken in the evening, especially during 
 
218 PHYSIOLOGY 
 
 the cooler seasons of the year, but the cold water tonic bath 
 may best be taken in the morning. A tonic bath may be 
 taken either as a plunge bath, as a shower bath., or as a 
 sponge bath. In any ease the surface of the body should 
 be wet only for a few moments in water of varying tempera- 
 ture from tepid to cold, and the wetting should be fol- 
 lowed by a vigorous rubbing with a coarse towel, and the 
 rubbing continued until the whole surface of the body is 
 red and glowing. Instead of making one take cold more 
 easily, this treatment fortifies one against the feeling of 
 cold or taking cold. It takes a very strong constitution 
 to stand a cold plunge bath ; even a cold shower, lasting 
 but a moment, is not advisable for a weak constitution 
 unless the glow comes quickly. The safest tonic bath 
 for a person not in vigorous health, is a cold sponge bath 
 on one portion of the body at a time ; each portion in turn 
 being exposed, sponged, and rubbed until aglow. 
 
 III. CLOTHING 
 
 Life in the changeable climate of the temperate zone 
 makes it necessary for man to have some other protection 
 than that which Nature provides him. Besides this prime 
 necessity, there is the inclination on the part of all civilized 
 human beings to wear clothing. Primitive man dressed 
 in the skins of animals ; in the colder climates the over- 
 coat made from the pelts of animals is the best protection 
 against the low temperature. 
 
 Clothing is made mostly from wool, cotton, silk, linen, 
 leather, and fur. A fundamental rule for the clothing 
 of the body is, clothe the body so as to make it comfort- 
 able. To be comfortable the clothing must fit the body 
 closely enough to conform readily to all of its move- 
 
THE SKIN 219 
 
 ments. Among these body movements must be mentioned 
 first, the respiratory movements ; no person should wear 
 clothing so close about the waist as to hinder in any way 
 the freest movements of respiration. The movements of 
 the arms should be perfectly free and unhampered by the 
 clothing. 
 
 The shoes should not be so tight that one cannot move 
 his toes ; if this rule is not observed the toes will become 
 distorted and covered with corns. Because of the per- 
 spiration which is constantly going on and the shedding 
 of the scarfskin, garments that are worn next to the skin 
 in the daytime should be removed at night. 
 
 rV. THE INFLUENCE OF ALCOHOL UPON THE SKIN 
 
 As already stated in a previous lesson, alcohol dilates 
 the arterioles and capillaries of the skin. If alcohol be 
 used in comparatively small amounts for a long period of 
 time, the capillaries of the skin become permanently di- 
 lated, thus giving the skin, especially of the face, a very 
 red appearance, and the little dilated capillaries may be 
 seen running their crooked course just beneath the surface 
 of the skin. When the skin becomes thus changed, it 
 cannot properly perform its portion of the work of 
 excretion, and so the kidneys have to do a portion of 
 the work which the skin ought to do, and thus they 
 become overworked. 
 
 3. THE SKIN AS AN ORGAN OF GENERAL 
 SENSATION 
 
 The nerves of the skin have been mentioned. Most 
 of the nerve endings are sensory nerves, whose work it is 
 to bring to the brain messages announcing the condition 
 
220 PHYSIOLOGY 
 
 of tlie skin or the condition about the skin. Figure 51 
 shows a thin slice of the true skin, with four papillae on 
 its surface ; two of these papillse have capillary loops, and 
 are therefore called vascular papillce, while two of them 
 have curious little bulb-shaped nerve endings, which are 
 organs of the feeling, or tactile corpuscles, and so the 
 papillae which have these corpuscles are called tactile 
 papillce. 
 
 There are other kinds of nerve endings in the skin. 
 Some nerves end in fine fibrils, which pass up into the 
 lower layer of the cuticle, but all these nerves bring 
 sensation to the brain, and are therefore called sensory 
 nerves. All parts of the skin are se'nsitive to touch and 
 to changes of temperature, though some parts of it are 
 more sensitive than others. The finger tips and the lips 
 and tongue are more sensitive to touch than any other 
 parts of the skin. The reason why these portions of the 
 body are more sensitive to touch is because they have 
 been. most used, and, therefore, most developed. Because 
 the senses of touch and of temperature are possessed by 
 all parts of the skin, these senses are called general senses. 
 A special sense is one which possesses a special organ. 
 
 Taste, smell, hearing, and sight,- possessing special 
 organs in the tongue, nose, ears, and eyes, are called 
 special senses ; while touch, temperature sense, and the 
 sense of position of the body, are general senses. There 
 are, therefore, four special senses and three general senses. 
 
 I. THE TACTILE SESSB 
 
 How lightly can you touch the tip of one of the hairs 
 on the back of your hand or arm without feeling it ? 
 How small a piece of match stick can you drop upon 
 
THE SKIN 
 
 221 
 
 the back of the hand, from the distance of two inches 
 above the back of the hand and feel it? If you have a 
 pair of draughtsman's 
 
 compasses, oi' dividers, i-vk ■>■• 
 
 or a pair of sharp- ,ik^* lt'7$ •^t*^"' 
 
 pointed scissors, see 
 how close together you 
 can hold the points and 
 feel them as two points 
 when tliey touch the 
 skin. At the finger 
 tips, one can feel them 
 as two points at a dis- 
 tance of less than an 
 eighth of an inch. 
 
 How far apart must they be to feel them as two points on 
 the back of the hand, on the palm of the hand, on the lips, 
 on the cheek, on the throat, on the back of the neck, on 
 the forehead ? When blindfolded, how much can you tell, 
 by feeling alone, about an object which may be handed 
 to you ? 
 
 i^--'^^';^! 
 
 Fig. si. — 0, nerve fiber; b, tactile papillae, 
 containing a tactile corpuscle ; c, vascular 
 papillae. [Alter JBenda.] 
 
 II. THE TEMPERATURE SENSE 
 
 Take a lead pencil which has been cooled in water or in 
 cold air, and move the lead lightly over tiie back of the 
 hand. Sometimes it will feel cold, and sometimes you have 
 no temperature feeling at all. You will merely feel the 
 lead moving over the hand. If you were to warm the 
 lead by dipping the pencil into warm water, and move it 
 similarly over the back of tlie hand, you would find that 
 sometimes it would feel warm, and that sometimes you 
 would have no sensation of temperature from this warm 
 lead. From this we learn that the skin is divided into 
 
222 PHYSIOLOGY 
 
 little areas, some of which are sensitive to cold, and some 
 of which are sensitive to heat, while there are still other 
 areas sensitive to neither cold nor heat. By cold and 
 heat as used here, we mean, of course, substances colder 
 than the skin or warmer than the skin ; because any- 
 thing that is colder than the skin will feel cold, while 
 anything warmer than the skin will f-eel warm. A thing 
 which may feel cool sometimes may feel warm at other 
 times, though at the same temperature. For example, if 
 one has three dishes of water standing upon a table, the 
 one at the right hand having cold water, the one at the 
 left, warm water, and the one between the two, tepid 
 water ; if he holds the right hand in the cold water, 
 and the left hand in the warm water, for one or two 
 minutes, and then takes the hands but and places them 
 both in the tepid water, it will feel cold to the left hand 
 and warm to the right hand. 
 
 The temperature sense warns the animal of the changes 
 of temperature in the air or water surrounding it, so that 
 he may adapt himself to the change. A part of the adap- 
 tation which the animal makes is an unconscious one, 
 made through the sympathetic nervous system, and con- 
 sists of the withdrawal of the blood from the surface 
 when cold air first strikes the body, and a raising of the 
 hair on end, as described above. 
 
 in. THE SENSE OF POSITION 
 
 If one were blindfolded and laid ujjon a table, he could 
 easily tell if the table were lifted or tipped a little in one 
 direction or another ; he could easily tell the direction, 
 and he might even tell the amount, unless the movements 
 were very, very slow. One can walk with the eyes shut, 
 or blindfolded, and maintain the erect position when rid- 
 
THE SKIN 223 
 
 ing a bicycle. Though we do all these with the greatest 
 ease,- it is really a most difficult thing to do, if one were to 
 stop to think about it, and something that takes a little 
 child nearly as long to learn as to learn to read. 
 
 Sensations are carried to the brain from the various 
 parts of the skin. If one is standing or walking, pressure 
 on the soles of the feet will tell in which direction the 
 body is swinging. On whatever part of the body one 
 rests, the skin from that part sends messages to the brain, 
 which enables one to tell the position of the body, or 
 changes in the position. The most important organ for 
 sending messages to the brain regarding the position of 
 the body is located within the internal ear. Through the 
 aid of this organ, the brain knows of all movements of the 
 head, whether from side to side, or forward and back, as 
 well as all movements of the whole body through space, 
 or the turning of the body, 
 
 REVIEW OF THE SKIN AND THE GENERAL SENSES 
 
 1. The skin is composed of the dead cuticle and the living dermis. 
 The dermis contains blood vessels, neroes, oil glqnds, hair follicles, and its 
 surface is covered with innumerable fine projections called papiUas. 
 
 2. The cuticle not having life is also -without feeling. Its workis 
 io protect the sensitive tissues which lie beneath it. The oil from the 
 oil glands keeps the skin soft and protects it against tlie absorption of 
 water. The hair, or the feathers, scales, or plates, are modified cuticle 
 and serve for protection. Nails, horns, and hoofs are also modified 
 cuticle and serve for protection. 
 
 3. The skin helps to regulate the temperature of the body by the 
 perspiration. 
 
 4. Because of the secretion of oil and of perspiration by the skin, 
 this organ becomes soiled and must be cleansed with warm water 
 and soap. 
 
 5. A tonic morning bath with cool or evem cold water followed by 
 
224 PHYSIOLOGY 
 
 brisk rubbing until the surface of the body is red and warm, is an 
 excellent hygienic custom. 
 
 6. Clollie the body in such a manner as to make it comfortahle. 
 
 7. If alcohol is used in moderate quantities for a long period of 
 time, the capillaries become permanently dilated, thus giving the skin 
 a permanent red color. 
 
 8. There are three cjeneral senses and four special senses. The 
 general senses are : Touch, or the tactile sense, the temperature sense, 
 and the sense of position of the body. 
 
 9. How may one test the tactile sense ? Where is this sense most 
 acute? Is it more acute in some persons than in others? 
 
 10. How may one test the temperature sense ? Why are animals 
 provided with this sense? How does the horse adapt himself to a 
 sudden change in the temperature from warm to cold? How does 
 man adapt himself under similar conditions ? 
 
 11. How is the brain made conscious of the position of the body 
 when one is standing, sitting, or lying? Of what use is this sense? 
 
CHAPTER XI. —THE SPECIAL SENSES — HOW 
 ONE KNOWS WHAT IS GOING ON ABOUT 
 HIM 
 
 The preceding lesson described the general senses, which 
 are so called because they do not possess a special organ. 
 The special senses, on the other hand, are so called because 
 the sensation is received by a special organ, which has no 
 other function, and which is specially litted for that par- 
 ticular function. 
 
 1. TASTE AND SMELL 
 I. THE SENSE OF T^STE 
 
 The special organ of taste is the taste bud, of which there 
 are many hundreds, perhaps thousand's, located on the sur- 
 face of the tongue, and perhaps sparingly on the palate 
 and sides of the pharynx. If you examine the surface of 
 the tongue in the looking-glass, you will notice little red 
 dots all over it. These dots are little funguslike papillae. 
 If you can see the tongue very far back, you may see sev- 
 eral very much larger papillae. All around the sides of 
 the large papillae at the base of the tongue and the small 
 funguslike papillae, there are little spherical bodies, com- 
 posed of many spindle-shaped cells, between which lie the 
 fine hairlike endings of the nerves of taste. 
 
 When a fluid substance, or a solid substance dissolved 
 in the fluid, or one which ma)'' be dissolved by the saliva, 
 is taken into the mouth, it comes into contact with these 
 
 225 
 
226 PHYSIOLOGY 
 
 minute taste buds, passes in between the spindle-shaped 
 cells which form the taste buds, and stimulates the end- 
 ings of the nerves of taste. This nerv.e sends the message 
 to the brain, and one becomes conscious of the ta,ste of 
 the substance. Many of the sensations which we call 
 taste are quite as much smell as taste ; the flavor of coffee 
 and of roast meat is a sensation largely due to the sense 
 of smell rather than to that of taste. Sensations which 
 are combinations of taste and smell should be called 
 flavors. 
 
 There are only four different kinds of taste, — salt, sour., 
 hitter, sweet. Most of the sensations which come to us 
 while we are chewing our food, and e'specially most of the 
 agreeable sensations, are really flavors, and not taste at 
 all. When one has a cold in the head, and both nostrils 
 are completely stopped up, so that he can breathe only 
 through the mouth, the food tastes flat and flavorless. 
 This is sufficient proof that the flavors depend upon a 
 combined sensation of taste and smell. 
 
 lif ot all parts of the tongue are equally sensitive to these 
 different tastes. The back part of the tongue, in the neigh- 
 borhood of the large papillse, is especially sensitive to bit- 
 ter ; the sides of the tongue are especially sensitive to acid ; 
 the middle of the tongue is especially sensitive to salt ; 
 and the tip of the tongue, to sweet. 
 
 n. THE SENSE OF SMELL 
 
 The specialized organ for smell is the upper part of the 
 nose. The lower part, from the nostrils directly back- 
 ward, is one of the air passages and part of the respiratory 
 system, but all the upper part of the nose out of the 
 direct line of breathing is devoted exclusively to the sense 
 of smeU, and there are nerve cells in the nose which stand 
 
THE SPECIAL SENS'ES 227 
 
 ill the mucous membrane among the cells which pave the 
 membrane. 
 
 Odorous substances, in the form of gas or of minute 
 particles, may pass in with the inspired air or may pass 
 up from the pharynx with the expired air, as is the case 
 when one is chewing food. These odorous substances 
 become dissolved in the moisture which covers the mem- 
 brane in the upper passages of the nose. They then come 
 in contact with the nerve cells of smell in the membrane, 
 and these nerve cells send a message to the brain, and one 
 becomes conscious of the smell; i.e. he receives the sen- 
 sation of the smell. 
 
 The different kinds of taste we found to be limited to 
 four, but the different kinds of smell are innumerable. 
 
 Nature provides animals with these senses for a purpose. 
 It seems to be Nature's plan that animals should use these 
 senses in the choice of their foods. In the case of beasts 
 of prey, the sense of smell may be u§ed in tracing their 
 prey. These senses guide herbivorous animals in tlie 
 choice of herbage. A poisonous weed is rarely mistaken by 
 them for a wholesome one. 
 
 Man can be guided by his sense of smell as to the 
 wholesomeness of the air which he is breathing, and his 
 taste will serve in part as a guide to the choice of food. 
 
 An odor is remembered longer than any other sensa- 
 tion. This sensation calls up more quickly and forcibly 
 some past experience than does any other sense im- 
 pression. 
 
 To smell things simply because they produce a pleasing 
 sensation, and to taste and eat or drink things simply 
 because the taste or flavor is a pleasing sensation, is a 
 perversion of Nature's laws which may be observed in 
 man only, of all animals. 
 
228 
 
 PHYSIOLOGY 
 
 2. HEARING 
 
 The ear is the special organ of the sense of hearing. 
 That part of the ear which we can see on the outside of 
 the head is only a sort of funnel for catching the sound 
 and conducting it into the part of the ear where the sound 
 is heard. The outer ear, together with the passage to 
 the ear drum, is called the external ear. The middle ear, 
 or eardrum, is a little cavity in the sojid bone of the side 
 of the head. Still deeper in the bone is the internal ear, 
 
 composed of a vestibule, 
 from which open a 
 coiled chamber similar 
 to a snail shell, called 
 the cochlea, and three 
 semicircular canals. 
 
 The middle ear is 
 called the tympanum, or 
 eardrum, because of its 
 resemblance to a drum. 
 As you know, a drum 
 has at least one drum- 
 head, which is a vibrat- 
 FiG. 52. — Section of the ear, showing the iug membrane. Every 
 
 relative positions ol the external, middle, rl i.rim ja nrnvided with a 
 and internal ear. [Tracy.] ^ 
 
 side opening. If this 
 side opening were not provided, the niembrane would not 
 vibrate freely, and the drum would have a dead, muffled 
 sound. The side opening into the tympanum is provided 
 by the Eustachian tube, a small canal which passes from 
 the pharynx up to the middle ear. 
 
 These parts which have been described are shown in 
 Figure 52. Study carefully this figure. Notice that the 
 
THE SPECIAL SENSES 229 
 
 middle ear, or tympanum, is divided from the canal which 
 passes in from the external ear by the drum membrane^ and 
 tliat it is divided from the vestibule by a little membrane 
 across what is called the oval window. Between the drum 
 membrane and the oval window is a chain of three bones. 
 The one which is attached to the drum membrane is called 
 the hammer, the one which is attached to the membrane 
 of the oval window is called the stirrup, and the one 
 between, fastened to the hammer at one end and to the 
 stirrup at the other, is called the anvil. 
 
 When the sound which passes in through the canal of 
 the external ear makes the drum membrane vibrate back 
 and forth, the hammer vibrates with it, and passes the 
 vibration on through the anvil and stirrup to the mem- 
 brane of the oval window. So the sound vibrations 
 received by the ear are thus carried direct to the mem- 
 brane of the oval window. The vestibule, cochlea, and 
 canals, of the internal ear are filled with liquid; the 
 vibrations of the membrane of the oval window set the 
 liquid into vibration. 
 
 There is stretched across the cochlea, from its center to 
 its circumference, a membrane composed of thousands of 
 little fibers lying side by side, some loug and some short, 
 those at the upper end being about twelve times as long 
 as those at the lower end, reminding one of a harp with its 
 long and short strings. The vibrations of the liquid set 
 these fibers to vibrating. Upon the fibers stand cells, 
 about which are the fibers of the auditory or hearing 
 nerve. The vibrations of the fibers stimulate the nerves, 
 and we become conscious of the sound. 
 
 The sense of hearing is one of the most useful to man 
 and to other animals, because it may warn man of 
 approaching dangers when they are still at a considerable 
 
230 PHYSIOLOGY 
 
 distance. It enables him to hear at a great distance a 
 call for help or a shout of warning. It enables him 
 through conversation to communicate his ideas to others. 
 Through the ears we are made conscious of the joys and 
 sorrows of our comrades ; we hear their laughter as ^ell 
 as their sobs. 
 
 It is a part of Nature's plan for the sense of hearing to 
 be cultivated and gratified for simple pleasure. It may 
 be observed even in the habits of the lower animals. The 
 summer night concert of the frogs a*nd crickets, and the 
 summer morning concert of birds, are sufficient evidence 
 that the voice and the hearing are to be cultivated 
 together for the entertainment and the pleasure of one's 
 self and others. Music is elevating and enriching in its 
 influence. 
 
 The most important thing to remember in the care of 
 the ears is that no hard or irritating substance or instru- 
 ment should be put into the canal of the ear, because there 
 is danger of injuring the delicate drum membrane. If 
 wax collects in the ear canal it may be gently removed 
 with the little finger, covered with a handkerchief or 
 wash-cloth. If the wax hardens in the ear, which fre- 
 quently happens, causing some pain, it may be softened 
 with one or two drops of sweet oil, or of fluid cosmoline, 
 after which it can be easily removed with an ear spoon. 
 
 3. THE SENSE OF SEEING 
 
 The eye is the special organ of this special sense. The 
 eye is one of the most complex organs of the body, 
 and the sense of sight is the most important of the 
 special senses. Figure 63 shows what you could see in a 
 comrade's eye if you were to look at it very carefully, 
 
THE SPECIAL SENSES 
 
 231 
 
 Fig. 53. — The eyelashes and the tear 
 glands ; G, tear gland ; D, Island around 
 which the tears collect ; C, tear canals ; 
 S, tear sac ; B, nasal duct through which 
 the tears drain off into the nose. 
 
 using, perhaps, a reading glass to magnify the parts some- 
 what. The eyeball is movable under the lids, and has a 
 dense coat which shows 
 in the corners of the 
 eyes, but directly in 
 front you see the black 
 pupil of the eye, sur- 
 rounded by the colored 
 disk, brown in some eyes 
 and blue or gray in 
 others. 
 
 The eyeball is so deli- 
 cate in its construction 
 that it must be very 
 thoroughly protected 
 from dust and all other 
 injurious things. These 
 protective parts, including the lashes, the brow, and tear 
 apparatus, are called the appendages of the eye. The eye- 
 lids are the most important protection of the eye, keeping 
 its transparent central portion moist and free from dust. 
 Notice that the margins of the lids are supplied with long, 
 stiff hairs. These are the eyelashes, and they assist in 
 protecting the eye from dust. On the edges of the lids, 
 notice the little dots. These mark the openings of minute 
 oil glands within the lids. These oil the edges of the lid, 
 to keep the tears from overflowing. 
 
 Above the outer corner of the eye and under the brow 
 is a gland about as large as the last joint on your little 
 finger. This is the tear gland, and its secretion, mostly 
 water, with a little salt and mucus .in it, pours through 
 the little ducts under the upper lid. When one winks 
 the eye, the upper lid spreads the tears over the surface, 
 hall's phts. — 15 
 
232 PHYSIOLOGY 
 
 thus washing off the dust and making the surface fresh 
 and bright. The tears are constantly evaporating from 
 the surface of the eyeball, but there are always some left 
 over, and these gradually collect down at the inner corner 
 of the eye around a little island, which is marked D in 
 the picture. On either side of this little island are two 
 minute pores, leading into the tear canals, marked C in 
 the picture. The two canals come together in what is 
 called the tear sac, from which a large duct, called the 
 nasal duct (-B), conducts the tears into the nasal passage. 
 If the tears flow rapidly, as when one is crying, they may 
 come too fast to flow off through the little canals, and so 
 may overflow upon the face; in that case they will also 
 flow freely from the nose. 
 
 Among the appendages of the eye are the muscles 
 which move the eye. These are six in number. One 
 muscle turns the eye inward toward the nose, while the 
 one opposite to it turns it outward. Then there are 
 muscles which turn it upward or downward or obliqueljr. 
 Sometimes one of these muscles is permanently contracted, 
 thus keeping the eye turned in ; then we say the person 
 is cross-eyed, or has a squint. A specialist is usually 
 able, by a simple operation, to loosen the muscles enough 
 to straighten the eye. 
 
 The eyeball is nearly spherical, and has a dense outer 
 coat called the sclerotic coat. The front part of this 
 coat is curved outward and transparent, reminding one of 
 a watch crystal. This is called the cornea, and through 
 this the rays of light pass into the eye (Fig. 54). 
 Just within the sclerotic coat is the choroid, which is a 
 loose-meshed tissue, full of blood vessels and nerves. 
 This coat contains an important muscular body called 
 the ciliary muscle, and it is this coat which makes the 
 
THE SPECIAL SENSES 
 
 233 
 
 little colored curtain called the iris. This little curtain, 
 the iris, is like the diaphragm of a ca=aiera, and through it 
 there is a circular opening called the pupil. The mus- 
 cles which it contains may dilate or contract the pupil 
 according to the amount of light, or according to whether 
 the object looked at is near or far away, — contracting to 
 see near objects and dilating to see distant objects. The 
 
 Fig. 54. — Horizontal section of the eyeball : d, sclerotic coat ; c, cornea ; c, 
 choroid coat; i, iris'; Aq, aqueous humor; a, crystalline lens; /t, vitreous 
 humor; b, retina; 0, optic nerve; cm, ciliary muscle; B, place vfhere 
 muscles were attached. 
 
 light which enters the eye through the cornea, passing 
 through the pupil of the eye, must be focused upon the 
 sensitive portion of the eye, the retina. The focusing is 
 done by the crystalline lens. The crystalline lens is held 
 in place by little ligaments, which pass out from the 
 ciliary muscle. The contraction of this muscle will cause 
 the lens to become more convex, thus focusing the light 
 from near objects upon the retina. 
 
234 PHYSIOLOGY 
 
 The retina is composed of two cpats, the outer coat 
 consisting of a sepia-black pigment, which absorbs the 
 light, while the inner coat (shown white in the figure) 
 consists of the nerve cells of sight. The eye nerve or 
 optic nerve passes from the base of the brain direct to the 
 ball of the eye, and enters it at 0, Figure 54, the fibers 
 spreading out to pass to the nerve cells of the retina. 
 The most sensitive part of the retina is just at the outside 
 of the optic nerve, and is marked m.l. in the figure. 
 That part of the ej^eball in front of, the crystalline lens, 
 and back of the cornea, is filled with a limpid, transpar- 
 ent fluid called the aqueous humor, while that part back 
 of the crystalline lens and comprising most of the ball is 
 filled with a viscid liquid of much greater consistency 
 than the aqueous humor, which is called the vitreous 
 humor. 
 
 These general rules may be given for the care of the 
 eyes : — 
 
 I. Never read by a dim light. 
 
 II. Never read by a flickering or rapidly changing light. 
 
 III. Never read in too bright a light, for example, when 
 the sun is shining full upon the page. 
 
 IV. Let the light shine upon the page and not upon the 
 eyes. The light should fall upon thfe page from the side 
 or from behind. 
 
 When the eye is at rest, distant objects are focused 
 upon the retina ; to see near objects it is necessary for 
 the muscle which controls the lens to contract ; to look 
 constantly at near objects requires a constant contraction 
 of this muscle. We know how hard it is to keep a muscle 
 contracted for a long tim«, and we can see that it would 
 strain the eyes to look for a long time continuously at 
 a close object, so we can appreciate the next rule. 
 
THE SPECIAL SENSES 235 
 
 V. When reading a book or studying any close object, 
 either close the eyes or look off at a distant object every 
 few minutes to rest the eyes. If oile has used the eyes 
 too long and has tired them, bathing them in cold Avater 
 is to be advised. If one cannot see clearly distant objects, 
 or if one has headaches that cannot be definitely traced to 
 some o<iher cause, he should consult a physician to see if 
 the eyes need the assistance of glasses. The free use of 
 either alcohol or tobacco may cause a very serious injury 
 to the sight. 
 
 During the last few years railroad managers have observed the 
 injurious effect of alcohol upon their workmen when occupying posi- 
 tions that require delicacy of touch, keenness of vision, and aeuteness 
 of hearing. Not long since a large railroad corporation investigated 
 the conditions surrounding every accident that had occurred on its 
 lines during the preceding five years. It was found that forty per cent 
 of all accidents were due entirely or in part to drinking men. In 
 eighteen per cent it was strongly suspected that the drinking habits of 
 employees was the cause of the accidents. The company in a single 
 year lost property to the amount of one million dollars through the 
 incompetency of beer-drinking engineers and switchmen. 
 
 Michigan has passed a law which imposes a. heavy penalty upon those 
 railroad companies which employ men who are in the habit of using 
 alcoholic intoxicants. Railroad managers, as practical business men, 
 arc recognizing the utility of employing total abstainers as a measure 
 calculated to reduce financial losses on account of accidents. 
 
 Some railroad companies prohibit their employees from drinking 
 any kind of intoxicants or entering a drinking saloon during working 
 hours, while other railroad companies demand from their employees 
 the signing of a total abstinence pledge which shall hold good for 
 every hour of every day. 
 
 Tliis action of railroad managers shows tljeir appreciation of the 
 doctrine that even small quantities of alcohol impair the organs of 
 special sense, and that in order to do the hist work in railroad busi- 
 ness the workmen must have eyes, ears, and hands perfectly free 
 from the poisonous influence of alcohol. — J. W. Grosvenor, M.D., 
 Journal of American Medical Association, June, 1896, p. 126. 
 
236 PHYSIOLOGY 
 
 REVIEW OF THE SPECIAL SENSES 
 
 1. How many different kinds of taste are there? Name several 
 pleasing flavors. What is the special organ of the sense of taste ? 
 
 2. What is the special organ of the sense of smell ? Name several 
 odors or perfumes which are pleasing. 
 
 3. What seems to be Nature's plan for the use of the senses of 
 smell and taste ? 
 
 4. Describe the special organ of hearing j its three divisions and 
 the way each division is made and the work it does. 
 
 5. What reason have we for believing that it is in harmony with 
 Nature's plan that we cultivate the taste for music ? 
 
 6. How should the ear be cared for? 
 
 7. Draw a picture of the eye, showing all of the principal structures. 
 Describe the drawing, and tell what is the work of each one of the 
 structures. 
 
 8. Give the five rules for the care of the eyes. 
 
 9. Why cannot railroad engineers do their work so well if they 
 have been indulging in moderate drinks of alcoholic beverages? 
 
CHAPTER XII. — THE NERVOUS SYSTEM — 
 THE BRAIN, THE SPINAL CORD, AND THE 
 NERVES 
 
 The subject of this chapter is not a new one. The 
 reader will remember that in Chapter III of General 
 Physiology, under the heading, " How the Different Organs 
 are made to work in Harmony," the nervous system was 
 studied at considerable length. This chapter will not be 
 a repetition of what was given there, but an extension of 
 it. In order to understand what is to follow in this 
 chapter it will be necessary to review again carefully the 
 chapter just referred to. To that end you may look up 
 again the answers to the following questions. 
 
 I. In what respects is the animal body similar to a large 
 colony ? 
 
 II. How are the different individuals of a colony made 
 to work in harmony ? 
 
 III. How is a railroad company able to send over its 
 lines a large number of trains without having numerous 
 collisions ? 
 
 IV. "Why is it necessax-y that the work of the stomach 
 be done at any particular time ? Why cannot the stomach 
 secrete its juice at any time ? 
 
 V. What would happen if the change of rate of the 
 heart beat or if the change of rate and depth of respiration 
 should take place at any time without reference to what 
 the muscles were doing ? 
 
 VI. What two things are necessary in bringing harmony 
 
 237 
 
238 PHYSIOLOGY 
 
 of action among those who work for a great railroad 
 company? (For example, see beginning of Lesson 2, 
 Chapter III.) 
 
 VII. What is a nerve trunk f a nerve fiber ? a nerve cell ? 
 
 VIII. What is the sympathetic nervous system? 
 
 IX. How does the sympathetic system perform its work ? 
 
 X. What is the relation between the sympathetic sys- 
 tem and the spinal oord ? 
 
 XL How is a message sent from the brain to the 
 muscles of the arm? (See Lesson 3, Chapter III.) 
 
 XII. What is voluntary action? 
 
 XIII. In how many directions must messages be sent 
 when one sees something which he desires, and reaches 
 for it? 
 
 XIV. What is reflex action? 
 
 XV. Does the brain receive any sensation in the case 
 of a reflex action ? If so, when is thi« sensation received, 
 before or after the act occurs? 
 
 XVI. What is the relation between voluntary action 
 and automatic motion ? 
 
 XVII. What is habit, and what is its relation to 
 automatic action ? 
 
 1. THE STRUCTURE AND FUNCTION OF THE BRAIN 
 I. NERVE CELLS 
 
 Neevb cells are the most remarkable cells in the animal 
 body, for their variety in shape, as well as for their size. 
 Figure 55 shows a typical nerve cell. This cell came 
 from the spinal cord. Some of the cell bodies in the 
 spinal cord are so large that they may be seen with the 
 unaided eye, and have branches reaching from the cord to 
 the hand or foot. 
 
THE NEUVOUS SYSTEM 
 
 239 
 
 Notice in this cell in Figure 55 how irregular the 
 outline of the cell body is. Each little projection of 
 the cell body passes out into a treelike branch, and because 
 of their resemblance to a tree they are called dendrites. 
 
 The nerve cell, like other 
 cells, is composed of proto- 
 plasm. These cells have very 
 large nuclei, and one or more 
 nucleoli. The protoplasm of 
 the nerve cells is granular. 
 There is usually a collection 
 of pigment (Fig. 55, P) in 
 each cell. The dendrites are 
 protoplasmic branches of the 
 cell. The dendrites bring 
 messages to the cell. Through 
 the dendrites the cell body 
 may be in communication with 
 numerous other cells. Though 
 a cell receives messages from 
 various sources, it can send a 
 message in only one direction. 
 One of the extensions of the 
 cell is called a neurite. It is 
 the neurite which carries the 
 message away, and under no 
 circumstances can the neurite 
 bring messages to the cell, 
 long dendrite whicli may bring a message from a long 
 distance ; those nerve cells also have a neurite. The sen- 
 sory nerves, which carry messages from the skin to the 
 brain, are long dendrites ; the cell body is located near 
 the spinal cord, and the neurite passes into the cord. 
 
 Via. 55. — A nerve cell from the 
 anterior horn of the spinal uord. 
 The Dendrites carry messages to 
 the nerve cell and the Neurite 
 carries messages away from the 
 nerve cell. Neuroglia {N) is 
 the supporting tissue. Insulat- 
 ing material (S), pigment (P). 
 
 Some nerve cells have a 
 
240 PHYSIOLOGY 
 
 II. NERVE SUBSTANCE 
 
 The substance of the central nervous system, that is, 
 the spinal cord and brain, comprises two tissues, nerve 
 tissue and supporting tissue. The stipporting tissue is a 
 very fiue-meshed counective tissue called neuroglia (see 
 Fig. 55, N). Only a small amount is shown in that figure, 
 in order not to obscure the details of the nerve cell, but 
 the neuroglia tissue fills all the space between the cells and 
 nerves, serving really as a packing to hold the cells in place, 
 as we use excelsior for packing. It is the nerve tissue, made 
 up of nerve cells, which does the work of the system. 
 
 III. NEKVE CENTERS AND NERVE TRUNKS 
 
 The cell bodies are not scattered promiscuously through 
 the nervous system, but are gathered into groups. This 
 seems to afford easier communication from one cell to 
 another through their short-branclietl dendrites. Such a 
 group of cells is called a nerve center, and in its action on 
 the nervous system is similar to the central office of a tele- 
 phone system. To such a center there are fibers coming 
 from a distance bringing messages, and from the center 
 the message may be forwarded to one of the distant 
 parts of the system. 
 
 The nerve fibers which pass from the cell bodies or from 
 nerve centers are insulated one from another through the 
 means of a white substance which makes a sheath about 
 each fiber. A bundle of these fibers is called a nerve 
 tract while it is still within the spinal cord or brain, but 
 when it emerges from these organs and passes out as a 
 rounded nerve cord, we call it a nerve trunk. Because of 
 the insulating material which surrounds the fibers, nerve 
 trunks and nerve tracts are white iii color, and because 
 
THE NERVOUS SYSTEM 
 
 241 
 
 of the protoplasm of which nerve cells are made, the 
 nerve centers have a grayish color. This led the anat- 
 omists and physiologists in times past to classify nerve 
 substance as gray matter and white matter. 
 
 2. THE SPINAL CORD. AND BRAIN 
 I. THE SPINAL CORD 
 
 FiGUEE 56 gives a 
 view of the whole central 
 nervous system, with the 
 spinal cord as seen from 
 behind. The nervous 
 system may be said to 
 comprise two organs : 
 first, the brain ; second, 
 the spinal cord. The 
 spinal cord represents a 
 series of important nerve 
 centers, around which are 
 grouped bundles of nerve 
 tracts (Fig. 57). The 
 grayish outline of the 
 centers makes a figure 
 something like the letter 
 H when the cord is cut 
 across ; and all the sub- 
 stance outside of the H 
 represents tracts or bun- 
 dles of fibers which are 
 passing upward toward 
 
 Fig. 56. — Brajn and spinal cord, with the 
 thirty-one pairs of spinal nerves. 
 
242 
 
 PHYSIOLOGY 
 
 the brain or downward from the brain. They are simply 
 cut-off fibers in this picture (Fig. 57). 
 
 The centers for motion in this spinal cord are in the 
 front horns of the H. Reflex action has been described 
 in Chapter III. If we make a careful study of Figure 67, 
 we can see how this reflex action is brought about. Sup- 
 pose something irritates the skin. A message is carried 
 along the long dendrite reaching from the skin to the 
 
 Fig. 57. — A diagram of a slice of tlie spinal cord as seen from behind, to show 
 how the sensation is conveyed to the ganglia of the posterior root through 
 the long dendrite D, thence to the cord through the neurite N. Arrived 
 in the cord it may go to the brain as at B' or B". But instead of passing 
 to the brain it may pass to the cells of the anterior gray hflrn, and cause a 
 reflex act. 
 
 nerve cell (the ganglion on the posterior root), and from 
 this cell body a message is forwarded along the neurite 
 into the posterior gray horn of the spinal cord, whence it 
 i.s communicated to the brain, as well as to the center of 
 motion in the anterior gray horn. Without waiting for a 
 reply from the brain, the cells of motion in the anterior 
 gray horn may send a message to the muscle through the 
 anterior root along the motor nerve, as shown in the 
 figure, and the muscle may contract, drawing the skin 
 away from the irritating object before even the brain 
 knows what is taking place. 
 
THE NERVOUS SYSTEM 243 
 
 II. THE BRAIN 
 
 Figure 56 shows the posterior view of the brain, com- 
 posed of the. great cerebrum, subdivided by the fissure into 
 two hemispheres, below which is the much smaller cerebel- 
 lum. Figure 58 shows more clearly tlie relative sizes of the 
 cerebrum and cerebellum, and shows the brain from a side 
 
 Fig. 58. — Side view of brain, showing the large cerebrum with its surface in 
 folds and fissures, the small cerebellum below the back part ot the cere- 
 brum, and the medulla passing downward from the base of the brain. The 
 word " Leg" shows where the brain is at work when it sends messages to 
 the leg ; similarly for head, arm, face, and for the organs of speech. " Hear- 
 ing " and " Vision " show where the brain receives the sensations of hearing 
 and sight. 
 
 view. The surface of the brain is thrown into a series 
 of very irregular folds, called convolutions. The pur- 
 pose of these convolutions seems to be to increase the 
 surface of the brain. It is upon the surface of the 
 brain that the cells composing the nerve centers are 
 located, while the internal portion of the brain is made 
 
244 PHYSIOLOGY 
 
 up largely of white fibers connecting different brain cen- 
 ters. By increasing the surface of the brain, the possible 
 number of cell bodies is increased, thus increasing the 
 brain activity. Highly civilized and. educated races of 
 men have brains which have more and deeper convolu- 
 tions than do the half-civilized and ignorant savages. The 
 savages, on the other hand, have more convolutions in 
 their brains than does the monkey or the dog, and these, 
 in turn, more than animals which stand still lower in the 
 scale. 
 
 The brain, then, represents a number of nerve centers 
 grouped into a compact mass. Different brain centers 
 preside over different functions of thci, body (Fig. 58, Leg, 
 Arm, etc.). As there are nerve trunks passing from the 
 spinal cord out to muscles and organ^j of sense, so from 
 the brain there are nerve trunks passing out to muscles 
 and nerve endings. Twelve pairs of these nerves extend 
 from the brain and from the medulla to various structures 
 of the head, face, throat, and thorax. 
 
 The cerebrum contains the centers which preside over, 
 or which are the seat of, consciousness of sensations, such 
 as of sight, sounds, odors, and feelings, as well as the cen- 
 ters of various emotions, such as fear, anger, love, hate. 
 It is the seat of all thought, of reason, and of the will 
 power. 
 
 The cerebellum is the center whieh presides over the 
 movements of the body and limbs, making these move- 
 ments smooth and graceful. It helps to keep the body 
 balanced in walking, standing, or riding. 
 
 In the medulla oblongata, shown in Figure 58, there are 
 numerous centers which preside over the movements of the 
 heart, the respiratory organs, and the various organs of 
 the digestive tract ; and which also preside over the con- 
 
THE NERVOUS SYSTEM 245 
 
 strictors and dilators of the arteries, changing the amount 
 of blood which is to flow to a particular organ at a par- 
 ticular time. 
 
 III. EDUCATION OF CORD AND BBAXN 
 
 As the muscles can be developed by systematic exer- 
 cise, so the nervous system may be cultivated and edu- 
 cated. Any particular act may be very hard to perform 
 at first, and may require the whole attention to perform 
 it even clumsily when it is first done, but, if often re- 
 peated, it may finally be done with perfect grace and pre- 
 cision, while one is thinking of something else. It thus 
 becomes an automatic action. Methods of thought, and 
 certain lines of thought, may become habitual in a meas- 
 ure, just as combinations of motions liiay become habitual 
 and automatic. This makes it a matter of very great 
 importance for all young people to cultivate correct habits 
 of action and of thought. 
 
 3. THE HYGIENE OF THE NERVOUS SYSTEM 
 I. EXERCISE AND REST 
 
 Like all other tissues of the body, nerve tissue requires 
 a certain amount of exercise and a certain amount of rest, 
 if it is to be vigorous and healthy. A§ all of the knowledge 
 which we possess comes to us through sensation, it is very 
 important that the acuteness of sensation be cultivated. 
 This can be done only by close attention to things which 
 one is observing. One should train himself to give his 
 undivided attention to anything which he is observing 
 with his senses. If he is studying the color and texture 
 of an object through his senses of sight and touch, he 
 
246 PHYSIOLOGY 
 
 should give bis undivided attention to the study. If he 
 is listening to a lecture or a concert, he should give his 
 undivided attention to that, thus not only cultivating a 
 habit of concentration, but also cultivating the acuteness 
 of the senses. At least one or two hours of intense men- 
 tal activity is required each day, if the mind of a young 
 person is to develop a power of close application and 
 correct, logical thinking. 
 
 But tissues that work hard must also rest perfectly. 
 Perfect rest of the brain can be gotten only during sleep. 
 Every person should have from seven to eight hours of 
 sound sleep out of every twenty-four if he is to continue 
 in vigorous health throughout his allotted years. 
 
 H. THE INFLUENCE OF ALCOHOL 
 
 " Alcohol acts primarily on the nerve cells, changing 
 their granular matter, breaking up their nutrition, and 
 changing their dynamic force. This action is followed by 
 contraction of the dendrites, swelling and atrophy of these 
 fibers, also shrinking of cell walls, as in fatigue, and 
 coalescing and disappearance of the granular matter of 
 protoplasm." ^ 
 
 " Alcohol does not affect all the spinal cells equally, and 
 in the early stages the changes are rather indefinite, a 
 greater sharpness of contour being the most obvious. In 
 the cerebrum the cells appear as mere shadows, both sub- 
 stances disaj)pearing, whilst the nuclei are also altered. "^ 
 
 " Just why the alcohol should select a set of nerves on 
 which to act at one time and a different set at another 
 does not at once appear, but it is a well-authenticated fact 
 
 1 Journal of the American Medical Association, November, 1898. 
 
 2 London Lancet, October 31, 1896^ p. 1245. 
 
THE NERVOUS SYSTEM 247 
 
 that it has a selective power. Most likely the explanation 
 lies in the chemical or electrical condition of the white 
 substance at the time of action, or it may be attributable 
 to the different chemical constituents of the liquor used." ^ 
 
 "Professor Kraepelin of Heidelberg tried a number 
 of experiments on individuals, with the object of seeing 
 whether a small quantity of alcohol hindered the nervous 
 transmission of intelligence to the brain. Flags were 
 raised at a given distance, and the exact time was noted 
 when the various men experimented upon observed the 
 raising of the flag. The result proved that the watchers 
 who had been given a small quantity of alcohol, though 
 they felt that they had seen the flag rise sooner than those 
 who had received no alcohol, actually took longer." 
 
 Professor Woodhead says, " After careful examination 
 of the whole question, physiologists — and among physi- 
 ologists I include those who maintain alcohol may be 
 useful, as well as those who hold that it is harmful — 
 have come to the conclusion that the principal action of 
 alcohol is to blunt sensation, and to remove what we may 
 call the power of inhibition by blunting the higher centers 
 of the brain." 
 
 Professor David Starr Jordan in the Popular Science 
 Monthly^ February, 1898, said : " The healthy mind stands 
 in clear and normal relations with Nature. It feels pain 
 as pain. It feels action as pleasure. The drug which 
 conceals pain or gives false pleasure when pleasure does 
 not exist forces a lie upon the nervous system. The 
 drug which disposes to reverie rather than to work, which 
 makes us feel well when we are not well, destroys the san- 
 ity of life. All stimulants, narcotics, tonics, which affect 
 the nervous system in whatever way, reduce the truthful- 
 
 1 Dr. Wilkins, in the New York Medical Journal, Septemljer 22, 1894. 
 hall's piiys. — 10 
 
248 PHYSIOLOGY 
 
 ness of sensation, thought, and action. Toward insanity 
 all such influences lead ; and their effect, slight though ■ 
 it be, is of the same nature as mania. The man who 
 would see clearly, think truthfully, and act effectively 
 must avoid them all. Emergency aside, he cannot safely 
 force upon his nervous system even the smallest false- 
 hood." 
 
 Dr. Hammond said : "The more purely intellectual quali- 
 ties of the mind rarely escape being involved in the general 
 disturbance [caused by alcohol]. Tliie power of applica- 
 tion, of appreciating the bearing of facts, of drawing dis- 
 tinctions, of exercising the judgment aright, and even of 
 comprehension, are all more or less impaired. The mem- 
 ory is among the first faculties to suffer. . . . The will 
 is always lessened in force and activity. The ability to 
 determine between two or more alternatives, to resolve 
 to act when action is necessary, no longer exists in full 
 power, and the individual becomes vacillating, uncertain, 
 the prey to his various passions, and to the influence of 
 vicious counsels." 
 
 " Helmholtz told us in his autobiography that if he took 
 wine while occupied with a mathematical or scientific 
 problem, his thinking powers were interfered with, and he 
 had to wait for the alcoholic effects to work off before his 
 inspiration returned." ^ 
 
 " Finally we have still to declare that alcohol hinders 
 the action of the highest mental faculties. A remark 
 made by Helmholtz at the celebration of his seventieth 
 birthday is very interesting in this connection. He spoke 
 of the ideas flashing up from the depths of the unknown 
 soul, that lies at the foundation of every truly creative 
 intellectual production, and closed his account of their 
 1 Dr. Adolph Rupp, New York Medical Joufnal, July 9, 1898. 
 
THE NERVOUS SYSTEM 249 
 
 origin with these words : ' The smallest quantity of an 
 alcoholic beverage seemed to frighten these ideas away.'"^ 
 
 W. Boyd Dawkins says : " I cannot drink beer when 
 I am using my brain, and do not take it when I have 
 anything to think about." ^ 
 
 " Some people imagine that after the use of alcohol they 
 can do things more quickly, that they are brisker and 
 sharper, but exact measurement shows that they are slower 
 and less accurate. Men believe that they are wiser and 
 brighter, but their sayings are more automatic and apt 
 to be profane. To quote Dr. Lauder Brunton, of Oxford 
 University, England, ' It produces progressive paralysis of 
 the judgment,'' and this begins with the first glass. Men 
 say and do, even after a single glass of drink, what they 
 would not say or do without it, and therefore it clearly 
 affects the brain and diminishes self-control."^ 
 
 Professor von Bunge,* of Switzerland, says that, " The 
 stimulating action which alcohol appears to exert on the 
 brain functions is only a paral3'tic action. The cerebral 
 functions which are first interfered with are the power of 
 clear judgment and reason. No man ever became witty 
 by aid of spirituous drinks. The lively gesticulations and 
 useless exertions of intoxicated people are due to paralysis, 
 — the restraining influences, which prevent a sober man 
 from uselessly expending his strength, being removed.' 
 
 " The capital argument against alcohol, that which must 
 eventually condemn its use, is this, that it takes away all 
 
 1 Adolph Pick, Professor of Physiology ,Wurzbnrg, Germany. 
 
 2 Quoted by Dr. M. L. Holbrook, Journal Medical Temperance Asuocia- 
 tion, January, 1898, p. 21. 
 
 8 Dr. G. Sims Woodhead, Professor of Pathology, Cambridge University, 
 England. 
 
 * G. von Bunge, Professor of Physiological Chemistry, University of Basel, 
 in Text-book of Physiological and Pathological Chemistry. 
 
250 PHYSIOLOGY 
 
 the reserved control, the power of mastership, and therefore 
 offends against the splendid pride in himself or herself which 
 is fundamental in every man or woman worth anything." ^ 
 
 III. THE EFFECTS OF TOBACCO UPON BRAIN WOEK 
 
 " I have been a teacher in Connec.ticut twenty years. 
 ... In boys addicted to this (tobacco) habit I find a 
 nervous irritability, and inability t6 do the work that 
 properly belongs to boys of their age. Where the habit 
 has been abandoned, I have found a marked improvement, 
 both mentally and physically."^ 
 
 REVIEW OF THE NERVOUS SYSTEM 
 
 1. Before going on with this review be sure that you can answer 
 the seventeen questions at the beginning of this chapter. 
 
 2. Draw a figure of a nerve cell ; draw and describe the dendrites. 
 What is the neurite ? 
 
 3. How many kinds of tissue are there in the nervous system ? 
 
 4. What are nerve centers? 
 
 5. Why was nervous tissue formerly classified as "white and 
 gray matter " ? 
 
 6. Draw a figure representing a section of the spiual cord. 
 
 7. Of how many main divisions is the brain composed ? 
 
 8. Of what importance are the convolutions of the brain? What 
 is the principal work of the Cerebrum? Of the Cerebellum? Of 
 the Medulla Oblongata? 
 
 9. How may the brain be i raproved ? Why does the brain need rest? 
 
 10. What is the effect of alcohol upon the brain ? 
 
 11. What is the effect of tobacco upon the brains of young and 
 
 1 Dr. John Johnson, quoting Walt Whitman. 
 
 'i Maria F. Starr, Principal High Street SehooJ, New London, Conn, 
 
CHAPTER XIII. —THE MUSCLES — HOW THE 
 BODY MOVES 
 
 1. THE MUSCLES: HOW THEY ARE MADE, HOW THEY 
 ARE ARRANGED, AND HOW THEY WORK 
 
 Figure 59 shows how the body would look if the skin, 
 and the layer of connective tissue and fat beneath the 
 skin, were all removed, leaving the muscles bare and 
 open to view. Though a great nunlber of muscles are 
 shown in the figure, those shown are only a small propor- 
 tion of all the muscles in the body ; the figure shows only 
 the outside muscles. 
 
 There are about five hundred voluntary muscles. The 
 voluntary muscles are those that are under the control of 
 the will ; the muscles of the legs, arms, body, neck, and 
 face are all voluntary muscles. These voluntary muscles 
 are, most of them, much larger than the involuntary, such 
 as those in the walls of the stomach and intestines, and 
 usually contract with a quicker and stronger action than 
 do the involuntary muscles. 
 
 By studying the limbs in the figure, especially the arm 
 at the right, you will notice that the upper or middle 
 portions of these muscles are large and full, and that from 
 the largest part of the muscle it tapers down to a small 
 cord at the wrist or ankle. This small cord at the 
 end of the muscle is not composed of muscular tissue, 
 but of very dense and inelastic connective tissue. If the 
 full, round muscle extended down over the wrists and 
 
 251 
 
252 
 
 PHYSIOLOGY 
 
 FiQ. 59. — The muscular system. [Tracy .] 
 
THE MUSCLES 253 
 
 ankles, it would make these as large around as the fore- 
 arm or calf, and that would make the wrist and ankle 
 very clumsy and awkward. 
 
 These glistening white cords spread out into a fan 
 shape at the end where the muscle attaches to it. This 
 glistening white cord passes over the wrist or ankle, down 
 to the hand or foot, where it is attached to the bone, and 
 through this tendon the muscle can move the hands and 
 feet, with their fingers and toes. Muscles are generally 
 attached to the bones at each end, and use the bones as 
 aids to accomplish their work. The bones serve as levers. 
 
 Fig. 60. — The arrangement of bones and muscles by which the arm is bent : 
 .4, the radius; B, the elbow; O, biceps; E, ulna; F, triceps; G, shoulder 
 joint. 
 
 Figure 60 shows the bones of the arm, together with 
 the two most important muscles. In the position in which 
 the arm is shown, the biceps muscle supports the weight 
 which is resting in the hand. The bones of the forearm, 
 that is, the radius and ulna, act as a lever. This lever is 
 fastened at the elbow joint, that is, the elbow is the ful- 
 crum of the lever. The biceps muscle represents the 
 power which pulls upon the lever between the fulcrum 
 and the weight resting in the hand. When the fulcrum, 
 
254 
 
 PHYSIOLOGY 
 
 the power, and the weight are arranged in this way, the 
 lever is said to be one of the third order. It is easy to see 
 that a slight contraction of the biceps muscle will move the 
 weight a greater distance than the actual contraction of 
 the muscle. In all levers of the third order, the weight 
 moves through a greater distance thafi the power, that is, 
 there is a gain in the distance moved by the weight, but a 
 loss in power. 
 
 Figure 61 shows the three orders of levers. In the 
 lever of the first order, notice that the fulcrum is between 
 the power and the weight. In the lever of the second 
 
 First order. 
 
 Wl 
 Second order. 
 
 Third order. 
 
 Fig. 61. — The three orders of levers. 
 
 order, the weight is between the fulcrum and the power, 
 while in the third order, the power is between the fulcrum 
 and the weight. In the lever of the first order, the power 
 will move through a greater distance than the weight, as 
 long as the fulcrum is nearer to the weight than to the 
 power, but when the fulcrum gets nearer to the power 
 than to the weight, then the weight will move through a 
 greater distance than the power. In a lever of the second 
 order, the weight is always nearer to the fulcrum than 
 the power is, and will, therefore, always be greater than 
 the power, and will always move through a smaller dis- 
 tance than the power. In the third order, the power is 
 always nearer to the fulcrum than the weight is, and will, 
 
THE MUSCLES 255 
 
 therefore, always be greater than the weight, and will 
 move through a shorter distance than the weight. 
 
 EXPERIMENTS AND PKOBLEMS 
 
 1. The leg of a chicken, including the toes and as much 
 of the drumstick as possible, may be obtained from a 
 butcher or from the kitchen. Remove the skin, and 
 separate out the muscles and tendons. Notice the effect 
 upon the movements of the toes when the different mus- 
 cles or tendons are pulled. 
 
 2. Refer to Figui-e 61. What order of lever is the 
 foot when one lifts his weight upon the toes by a con- 
 traction of the muscles on the back of the calf? What 
 kind of lever does the foot make when one, witliout 
 putting the heel upon the floor, lifts a weight which 
 •rests upon the toes ? 
 
 3. What kind of a lever is the lower jaw during the 
 process of chewing ? What lever is the foot when one 
 rests the weight of the body upon the heel ? 
 
 4. What order of lever does one niake of one's arm, if 
 one takes a weight in the right hand and holds the right 
 arm in such a way that the forearm will be horizontal and 
 above the head ; then, holding . tjie upper arm still, 
 straightens the arm, thus lifting the weight up? Per- 
 haps this problem could be understood better if you 
 should turn Figure 60 upside down. 
 
 2. THE HYGIENE OF THE MUSCLES 
 
 From what has been said in previous lessons, you know 
 that the work of the muscles consists in generating the 
 heat which keeps the body warm, and also in producing 
 
256 PHYSIOLOGY 
 
 the motions of the body. They produce these motions by 
 shortening and thus pulling up their tendons, and moving 
 the bones. The stronger the muscles, the more work 
 they are able to perform, both in warming the body and 
 in bodily movements. 
 
 The first thing required by the muscles is nourishing 
 food, and plenty of it. No part of the body is so sensi- 
 tive to changes in the food as is the muscular system. 
 
 I. EXERCISE AND REST 
 
 The muscles, like the brain and other organs, are devel- 
 oped by exercise. Nearly all young animals play. Play 
 is Nature's method for exercising the muscles, brain, and 
 senses. One should choose for exercise those move- 
 ments which require quickness and accuracy, rather than 
 those which require great strength. To most people, 
 calisthenics and individual gymnastips are uninteresting. 
 It has been shown by years of observation on the part of 
 men who have made a life study of the development of 
 the nerves and muscles, that the most wholesome exercise 
 is that obtained in games of skill and agility in which 
 several individuals are contesting. Engaged in such a 
 game, one loses all thoughts of himself and of the object 
 of his exercise in his endeavors to win points in the game. 
 Among the best games for the all-around development of 
 the body are tennis, basket ball, hand ball, baseball, cricket, 
 football, la crosse, and golf. 
 
 One should not exercise severely within half an hour 
 before a meal, or within half an hour after a light meal or 
 one hour after a heavy meal. Fatigue or weariness is 
 Nature's notice to take a rest. It has been stated in a 
 previous lesson that when the brain and the muscles both 
 
THE MUSCLES 257 
 
 call at the same time upon the circulatory system for more 
 blood, the muscles will get it, and the brain will go with- 
 out. For this reason, one should do' his studying first, 
 and his playing or work afterward. Some have not a 
 choice in the matter, and are obliged to study after their 
 work, if they study at all ; but if one has a choice of the 
 order in which he will perform his tasks, he will be wise 
 to do his brain work first, while the muscles are at perfect 
 rest ; then if he goes out in the latter part of the day and 
 takes vigorous muscular exercise, or does his muscular 
 work, he will withdraw the excess of blood from the 
 brain, thus making it easier for the brain to rest at night 
 in a dreamless, restful sleep. 
 
 II. THE EFFECT OF ALCOHOL ON THE MUSCLES 
 
 The use of alcoholic beverages decreases the muscular 
 power, as is shown by the following incident, quoted from 
 the Weekly Telegraph, London, 1897: An English con- 
 tractor, while erecting a large bridge in Scotland, was 
 surprised at the apparent muscular power of the High- 
 landers whom he engaged. Having contracted for exca- 
 vating a canal in England, he engaged about twenty 
 Highlanders to accompany him southward. Several 
 disputes occurred between these northerners and the 
 Englishmen with whom they worked upon the canal, and 
 the Highlanders were made the butt of many a jeer 
 relative to the simple bread and milk fare on which they 
 were contented to exist, thus saving* the greater part of 
 their wages to bring back to their friends and families. 
 To settle these disputes, a wager was made that twelve 
 Highlanders could not excavate a certain number of yards 
 in the same time as an equal number of the " better fed " 
 
258 PHYSIOLOGY 
 
 Englishmen. Everything being fixed, a table was laid 
 out with meat and ale for the Englishmen, while the 
 Scotch had, besides their bread and milk, no other prepa- 
 ration for refreshment except what a can of fresh water 
 afforded. But the point in dispute was, after a fatiguing 
 day's work, decided in favor of the Highlanders, and 
 while the Englishmen were totally exhausted by their 
 exercise, the Highlanders still had a good reserve of 
 strength and, in their enthusiasm at their success, danced 
 their national Strathspey in token of their victory. 
 
 Dr. DeVaucleroy, Professor of Hygiene in the Military 
 School of Belgium, says: "The influence of alcohol upon 
 muscular work has been established permanently. It has 
 been demonstrated that man works better when he does 
 not use these pretended stimulants. The physiological 
 experiments of Destree have established that alcohol is a 
 paralyzer of muscular work. It excites at first, but this 
 excitation is altogether transient, and is followed imme- 
 diately by depression." 
 
 English and American athletes have long recognized 
 the very great importance on the part of those who are to 
 enter contests, of total abstinence during the period of 
 training as well as during the period of contest. Nearly 
 ten years ago this began to be recognized among the 
 German university students, and one club after another 
 abandoned the morning drinking bout in order to better 
 fit themselves for athletic contests in which their members 
 wished to take part. 
 
 Dr. Charles Stewart says that, " In a number of experi- 
 ments carried out with the idea of ascertaining the effect 
 of alcoliol upon muscular force, it was found that in every 
 case where alcohol was taken, muscular force was dimin- 
 ished, even when so small an amount as one half dram 
 
THE MUSCLES 259 
 
 (one half a teaspoonful) of alcohol was used. In these 
 experiments it was found that nonabstainers were affected 
 as well as abstainers. The deceptive nature of alcohol 
 was manifested in every case, each individual feeling sure 
 that he could accomplish more than he could before 
 taking the alcohol. "^ 
 
 Many hundreds of similar experiments might be cited, 
 but they all demonstrate the same thing, namely, that the 
 use of alcohol decreases the force and efficiency of the 
 muscular system. 
 
 ALCOHOL AS AN AKMY RATION 
 
 "The uselessness, if not the harmf utness, of even moder- 
 ate doses of alcohol rests on better evidence than scientific 
 deduction and experiments. In connection with the sani- 
 tation of armies, thousands of experiments upon large 
 bodies of men have been made, and have led to the result 
 that, in peace and war, in every climate, in heat, cold, and 
 rain, soldiers are better able to endure the fatigues of the 
 most exhausting marches when they are not allowed any 
 alcohol. A similar result is observed in the case of the 
 navies and on thousands of commercial vessels belonging to 
 England and America, which put to sea without a drop of 
 alcohol. Most whalers are manned by total abstainers." ^ 
 
 In a paper entitled " War's Aftermath," in the May 
 Forum, 1899, Mr. W. K. Rose, Renter's correspondent in 
 the Soudan campaign, said : " Alcoholic drinks are, how- 
 ever, now eschewed by the best commanders. ' Havelock's 
 saints ' performed their heroic feat in marching and fight- 
 ing in the Indian mutiny on coffee alone as a beverage. 
 
 1 Journal of the Medical Temperance Association, January, 1897, p. 5i. 
 
 2 Professor Bunge. 
 
260 PHYSIOLOGY 
 
 In the Red River expedition of 1870, under General 
 Wolseley, no spirit ration was issued ; and certainly, says 
 the Medical Report, no men could have enjoyed better 
 health than did the troops without it. Out of the seven 
 hundred and ten men engaged only five were invalided. 
 The old-fashioned rum ration was not issued in the Ashan- 
 tee War of 1873, — which was also under the command of 
 General Wolseley, — though a small amount was given 
 to individuals when especially prescribed by the medical 
 officers. The result was that, in the pestilential climate 
 of the hinterland of the Gold Coast, the total mortality 
 from all causes was only 3.14 per cent of the whole 
 strength of the British troops. In the Kaffir War of 
 1877-1878 rum as a ration was strictly prohibited; and 
 the good health of the troops was attributed to enforced 
 abstinence from spirituous liquors." 
 
 Colonel Geary, in a paper before the Sanitary Con- 
 gress at Stafford, stated that during the Abyssinian cam- 
 paign, for six weeks advancing upon and retiring from 
 Magdala, there was no alcohol, no crime, and the per- 
 centage of sick was less than in any part of the British 
 army at home or abroad, while the troops performed 
 arduous marches on scanty food and often with bad water. 
 
 Lord Roberts, the commander in the Boer campaign, 
 says that the effective strength of an army is always 
 proportionately greater according to the number of total 
 abstainers in the ranks. 
 
 "To-day it is a great feather in the headgear of the 
 advocates of military total abstinence that Lord Kitch- 
 ener's recent victory was V70n for him by an army of tee- 
 totalers, who made phenomenal forced marches through 
 the desert, under a burning sun, and in a climate famed 
 for its power to kill or prematurely age the unacclimated. 
 
THE MUSCLES 261 
 
 Indeed, it is said that never has there been a British cam- 
 paign occasioning so little sickness and profiting by so 
 much endurance." 1 
 
 ALCOHOL A CAUSE OB* MENTAL DISOEDEES 
 
 " If 3'ou look round and try to find out the primary 
 causes of disease and poverty and crime and misery, you 
 are over and over again thrown back on the use of 
 alcohol. One cannot read the newspapers and reports 
 of judges without seeing that alcohol accounts for a very 
 large proportion of what is evil in our daily life. It is 
 sapping the foundation of our national life, and if we 
 could do away with all the disease and poverty and crime 
 caused by alcohol, the questions whiph confront us would 
 be solved very easily. "^ 
 
 THE INFLUENCE OF ALCOHOL UBON THE MORALS 
 
 " The most highly specialized characteristics are first 
 impaired, and thus the spiritual faculty, if I may so term 
 it, first becomes blunted by the use of alcohol. Fallow- 
 ing this in rapid succession there is blunting of the moral 
 sense ; a slight, though distinctly perceptible, interference 
 with the intellectual faculties, which leads to what we 
 might call blurring of the reasoning power ; then follows 
 a distinct diminution in the power of rapidity and accuracy 
 of perception. At none of these stages would a man admit 
 that be was under the influence of alcohol ; but these 
 powers are just as assuredly under its influence as are the 
 muscles which can no longer act coqrdinately to enable a 
 man to walk straight."^ 
 
 1 Washington Star. ^ Professor G. Simms Woodhead. 
 
 8 Professor Woodhead. 
 
262 PHYSIOLOGY 
 
 "The nervous system cannot escape injury from the 
 ingestion of . alcoholic drinks. It fails to receive correct 
 impressions ; it fails to send out correct orders ; it fails 
 to receive proper rest. . . . Tlie continued use of alcohol 
 causes the nervous centers to undergo degeneration, and 
 the most serious diseases known to medical science ensue." ^ 
 
 1 George H. McMichael, M.D., Buffalo, N.Y. 
 
CHAPTER XrV. — THE SKELETON — THE 
 FRAiVIEWORK OF THE BODY 
 
 The earthworm has no framework ; he cannot hold his 
 body erect, all of his movements must be slow and grovel- 
 ing. The butterfly has a framework. Portions of this 
 framework support the delicate, membranous wings, whose 
 framework is articulated to the body. Through the aid 
 of muscles which pass from the body to the framework of 
 the wings, these may be moved, and enable the butterfly 
 to fly out into the sunshine. 
 
 Man's body has a framework, — the bony skeleton, the 
 parts of which lie deeply buried in the muscles. Without 
 this framework man could not stand erect. The skeleton 
 of man is very much like the skeleton of other vertebrate 
 animals. AH vertebrate animals possess a vertebral col- 
 umn, which is called the axis of the body. 
 
 When the dog or cat is standing on all fours, his verte- 
 bral column is horizontal, and his fou-r legs pass downward 
 to the ground as supports. The four legs of the dog or cat, 
 together with the large flat bones which fasten them to the 
 vertebral column, are called the appendages of the body 
 axis, or the appendicular system. The axis of the body 
 comprises not only the vertebral column, but the skull, 
 as well as the ribs and sternum. The axis, or vertebral 
 column, of the cat or dog is extended backward beyond 
 the body, the bones getting smaller and smaller clear to 
 the tip of the tail. In the case of man and of the higher 
 apes, the axis, or vertebral column, does not extend be- 
 hall's phts. — 17 263 
 
264 
 
 PHYSIOLOGY 
 
 yond the body, but the last few bones of the vertebral 
 column are grown together into what appears, at first, to 
 be one large, strong bone, called the s*acrum, beyond which 
 
 is a little bone called the coccyx. 
 Figure 62 gives a side view of 
 the vertebral column, and shows 
 the curved sacrum at the bottom, 
 composed of five vertebrae joined 
 together. At the end of the 
 sacrum there is the little coccyx 
 of four buttonlike bones, usually 
 grown together. 
 
 ^ S5 S 
 
 si <o a 
 
 & ^ es 
 
 r. a rn 
 
 S 8' 
 
 a 
 
 S -H .O 
 
 B « a 
 
 C OJ 
 
 PROBLEMS 
 
 O OJ _ 
 
 b. P-i o 
 
 .-^ ig CO 
 
 « „ g 
 
 a oj 
 
 1. To what part of your body 
 does the paw of a cat correspond? 
 
 2. Find upon a cat's body the 
 part which corresponds to your 
 elbow. 
 
 3. Find the part which corre- 
 sponds to your knee. 
 
 4. Find tiie part which corre- 
 sponds to your heel. 
 
 5. Find upon a horse's body 
 the part which corresponds to 
 your elbow. 
 
 6. To what part of your body 
 does what 'W'e call the horse's 
 knee correspond? 
 
 7. To what part of your body does the horse's hoof 
 correspond ? 
 
 8. To what part of the horse's body does your heel 
 correspond ? 
 
 p? 
 
 !» <D S ^ 
 I ^^ . o 
 
 ■ S +^ S 
 
THE SKELETON 265 
 
 9. Observe a dressed chicken, and find upon the 
 chicken the part which corresponds' to your knee ; the 
 part which corresponds to your heel. 
 
 10. Find the part which corresponds to your elbow ; to 
 your wrist ; to your fingers. 
 
 1. THE HUMAN SKELETON 
 I. HOW THE BONES ARE GEODPED 
 
 FiGUEB 63 gives a front view of the human skeleton. 
 Notice that the first, or upper, joint of the arms has one 
 bone, the humerus ; and that the corresponding joint of the 
 legs has one bone, the femur. Notice, further, that the 
 second joint of the arm corresponds to the second joint of 
 the leg in having two bones. The third joint, or third 
 portion of the anterior limb, comprises the wrist and five 
 digits ; while in the leg, the corresponding portion com- 
 prises the ankle and five digits. Notice that the arms are 
 held in place by two large flat bones back of the ribs, 
 called the shoulder blades, and that the shoulder joint is 
 braced in front by the collar bones, which pass from the 
 shoulder blade to the sternum. The liximerus is joined to 
 the scapula with a ball and socket joint, the ball on the 
 end of the humerus fitting into a spherical socket in the 
 shoulder blade. In a similar way, the legs are attached 
 to the axial skeleton through two large, flat, irregular 
 bones called the innominate bones. The innominate bones 
 are firmly joined to the sacrum behind, and firmly united 
 together in front. This makes a strong basinlike founda- 
 tion for the whole body, called the pelvis. The leg bones 
 are joined to the pelvis by a ball ahd socket joint; the 
 other joints of the limbs are ?dnffe Joints. 
 
Fig. 63. — The skeleton. 
 
THE SKELETON 267 
 
 Count up the bones of the skeleton, and see how many 
 you can find. Not counting the teeth and the six little 
 ear bones, the skeleton is composed of two hundred bones. 
 Turning again to Figure 62, notice that the spinal column 
 shown there was sawed through the middle. This shows 
 the canal which passes up through the spinal column, and 
 within which the spinal cord lies. The cord is thus 
 thoroughly protected from harmful .pressure or injury. 
 Similarly the brain is always thoroughly protected within 
 the bony cranium which rests upon the top of the spinal 
 column. 
 
 In Figure 62 there seems to be space between the ver- 
 tebrae. These spaces are filled in the living body with a 
 firm, elastic cartilage, which gives sufficient opportunity 
 for the bending of the spine, and serves a most important 
 purpose as a series of cushions, which protect the brain 
 from the jarring it would otherwise suffer when one 
 walked or jumped on hard ground. 
 
 II. HOW THE BONES ARE MADE 
 
 Figure 64 shows the femur as it appears when sawed in 
 two, lengthwise. Notice that the two ends of the bone 
 are larger than the shaft, and that they seem to be made 
 differently inside. At the two ends of the bone we find 
 what is called cancellous tissue. It is made iip of little, 
 thin, bony plates so joined together as to make a very 
 great number of little compartments with thin, bony 
 walls. The little spaces within these bony cells are filled 
 with blood vessels and a tissue which is something like 
 gland tissue. This portion of the bones and similar tissue 
 wherever found in the body, especially within tlie ribs 
 and in the heads of the long bones, is called red marrow 
 
268 
 
 PHYSIOLOGY 
 
 and is the place where red blood corpuscles are formed. 
 
 The shaft of the bone is occupied by a very few blood 
 vessels, all the rest of the space 
 being filled with a deposit of 
 fat, giving the cut bone a yellow 
 appearance. This portion of the 
 bone marrow is called the yellow 
 marrow. 
 
 In infancy the bones are very lim- 
 ber and may be easily bent, because 
 they are composed mostly of cartilage 
 or gristle. As the child advances 
 in age, the bones get stronger and 
 stronger owing to a deposit of lime 
 within the bone tissue. If one takes 
 a chicken bone and soaks it in acid, 
 especially dilutejd hydrochloric acid, 
 he will find that the bone will grad- 
 ually get softer and softer until it is 
 limber enough to tie into a knot. 
 This change in the bone is due to 
 the mineral matter of the bone being 
 dissolved out. 
 
 On the other hand, if one puts a 
 bone into a fire and burns it until it 
 bouy fibers at the upper i^ white, thus burning out all of the 
 
 end, its peculiarity be- . . . i -ii ji j i. t. 
 
 ing somewhat exagger- animal matter, he Will find when he 
 ated so as to malie it ^^^^^ j^ g^^ of ^.j^g gj.g ^^i^^ ^^ jg 
 more plain. [Tracy.] , .^^, , , ,-,.,, 
 
 brittle and can be crushed in the 
 fingers. These two experiments teach us that a bone gets 
 its stiffness and hardness from the mineral matter and its 
 toughness and flexibility from the animal matter which it 
 contains. 
 
 Fig. 64. — The right femur, 
 or thigh bone, sawed in 
 two lengthwise. Notice 
 the arrangement of the 
 
THE SKELETON 
 
 269 
 
 III. HYGIENE OP THE BONES 
 
 From what has been said above it is evident that the 
 bones of growing children need mineral matter, and it is 
 further evident that this mineral matter must come through 
 the food. Nature's food for infants (milk) contains the 
 
 Fig. 65. — A represents the normal appearance of the ribs. S represents part 
 ol a photograph of the skeleton of a young wonian of twenty-three years, 
 showing the distortion of the ribs produced by tight lacing. [Tracy.] 
 
 mineral matter in sufficient' quantity and in proper propor- 
 tions. After the young child stops making milk its only 
 diet, its food must be chosen with some care in order to 
 provide it with plenty of bone-making material. The 
 cereal foods and the vegetables are the best for this pur- 
 pose. 
 
 The bones of young people and children are very easily 
 
270 PHYSIOLOGY 
 
 distorted or bent out of their proper shape because they 
 have not yet become stiff and hard through the naineral 
 matter, so it is important that little children in schools or 
 at home sliould not sit on high seats where the weight of 
 the lower legs and feet hangs from the end of the femur, 
 which rests upon the edge of the seat. Such treatment of 
 the femur would bend it out of its natural shape. 
 
 Children and young people should take great care to 
 hold their bodies erect when sitting, standing, walking, or 
 riding. This requires some effort and attention, but if it 
 is done faithfully, one not only gets a habit of erect car- 
 riage, but one's bones and muscles later naturally assume 
 these positions, thus giving a person a inuch more dignified 
 and stately bearing than would otherwise be possible. 
 Figure 65 should be a striking object lesson for those who 
 are inclined to wear clothing too tight to give perfectly 
 free movements for the thorax. In the figure at the 
 right, the vital organs, such as the lungs, heart, stomach, 
 liver, spleen, and pancreas, are all crowded into much nar- 
 rower space than they are intended by Nature to occupy. 
 This hinders them from doing their best work, and as 
 they are the organs which provide for the general nutri- 
 tion of the whole system and all the vital processes, it 
 must be evident that the health of an individual whose 
 chest is thus permanently deformed will sooner or later 
 be very seriously interfered with. 
 
INDEX 
 
 Absorption of food, 197. 
 
 Adam's apple, 168. 
 
 Air, changes in lungs, 179; comple- 
 mental, 173 ; composition of, 178 ; 
 impure, 186 ; reserve, 173 ; residual, 
 173; tidal, 172. 
 
 Alcohol, effects of, upon blood, 159; 
 blood corpuscles, 191; on digestion, 
 115; on heart, 159; on liver and 
 kidneys, 210; on muscles, 257; in- 
 fluence of, general, 69 ; on nervous 
 system, 246; on skin, 219; how 
 formed, 59; not a food, 110; relation 
 to animal heat, 191 ; relation to lung 
 diseases, 192. 
 
 Alimentary canal, 89. 
 
 Amoeba, one-celled animal, 34. 
 
 Apples, acid fruits, 87. 
 
 Arteries, 136, 138. 
 
 Automatic action, 55. 
 
 Barley, a cereal, 81. 
 
 Bathing, 217. 
 
 Bicuspid teeth, 91. 
 
 Bleeding, protection of body against, 
 131, 143. 
 
 Blood, 128; changed in lungs, 180; 
 coagulation of , 131 ; condition of, 158 ; 
 freed of carbon dioxide, 182 ; figured 
 and described, 129; nourishes tis- 
 sues, 144 ; oxygenated, 180 ; gives up 
 oxygen, 146. 
 
 Body heat, 184. 
 
 Bones, 263, 265, 267. 
 
 Brain, 238, 241, 243 ; education of, 245; 
 influenced by tobacco, 250. 
 
 Breathing, chest and abdominal, 174; 
 forced, 172, 
 
 Bronchi, 168. 
 
 CsEcum (se'cum) , 90. 
 Canine teeth, 91. 
 
 Capillaries, 139, 147. 
 
 Cardia of stomach, 93. 
 
 Cartilage, figure and description, 39. 
 
 Cell, described, 30; diagram of, 29; 
 
 lymph, 30; of plant, 30; plasm, 30; 
 
 work of, 28. 
 Cells, review of, 45 ; of body, 27. 
 Cereals, defined and described, 81; 
 
 experiments with, 83. 
 Chyle, ISa 
 Circulation, control of, 151; diagram 
 
 of, 140 ; review of, 162. 
 Circulatory system, 42. 
 Clothing, 218; eilect of, on skeleton, 
 
 270. 
 Coagulation of blood, 131. 
 Colon, 00. 
 
 Colony animal, 38 ; plant, 37. 
 Complemental air, 173. 
 Constrictors of blood vessels, 154. 
 Corn, plants, 12; a cereal, 81; kernels, 
 
 11. 
 Coughing, 175. 
 Crying, 176. 
 Cuticle, 213. 
 
 Desmids, one-celled water plants, 
 33. 
 
 Diaphragm, 167. 
 
 Digestion py gastric juice, 99 ; hygiene 
 of, 104; by pancreatic juice, 101 ; by 
 plants, 21; by saliva, 97; review, 
 103. 
 
 Digestive system, 42 ; figure of, 90, 91 ; 
 review of, 96 ; structure of, 89. 
 
 Dilators of blood vessels, 154. 
 
 Distillatioh, described, 61. 
 
 Domestic Economy, 118. 
 
 Drinks, alcoholic, 110 ; hygiene of, 107 ; 
 narcotic, 58; nourishing, 110; re- 
 freshing, 109; stimulating, 110. 
 
 Duodenum {dS-d-de'-num) , 89, 95. 
 
 271 
 
272 
 
 PHYSIOLOGY 
 
 Ear, description of, 228; hygiene of, 
 
 230. 
 Economy, domestic, 118. 
 Eggs, 78. 
 
 Energy o( life, generation of, 203. 
 Epidermis, 212, 213. 
 Ksopliagus, 81). 
 Excretion by kidneys, 207. 
 Exercise, 155 ; and rest, 256. 
 Experiments, in plant physiology, 21 ; 
 
 in respiration, 180; on cereals, 83; 
 
 on foods, 80 ; on vegetables, 86 ; with 
 
 gastric juice, 100; with pancreatic 
 
 juice, 102 ; with saliva, 98. 
 Expiration, 160, 172, 173. 
 Eye, description of, 233; hygiene of, 
 
 234. 
 
 Ferment, defined, 22. 
 
 Fermentation, 61, 63. 
 
 Fevers, 185. 
 
 Food, how used in body, 196; absorp- 
 tion of, 197. 
 
 Foods, 78; experiments on, 80, S3, 86; 
 review of, 89. 
 
 Fruit, 86 ; juices and sirups, 109. 
 
 Gastric juice, digestion by, 99. 
 Germ of plant, 20. 
 Gla,nd, described, 42. 
 
 Habit, SB, 57. 
 
 Hair, 212. 
 
 Harmony of work, nervous system, 40. 
 
 Hearing, sense of, 228. 
 
 Heart, 133, 134, 139. 
 
 Heat of body, 183, 
 
 Hiccoughing, 17G. 
 
 Hygiene, defined, 9; of bones, 269; of 
 circulation, 155 ; of digestion, 104 ; of 
 ear, 230; of eye, 234; of kidneys, 
 208; of liver, 208; of muscles, 255; 
 of respiration, 186 ; of skin, 216. 
 
 Ileum (ll'e-um) , 89. 
 Incisor teeth, 91. 
 Inspiration, 166, 172. 
 Intestines, 89, 95, 96. 
 Iodine, test for proteid, 21; test for 
 starch, 21. 
 
 Jejunum (^'e-,;M'n«m) , 89. 
 
 Kidneys, description of, 207, 208. 
 
 Lacteals, 150. 
 
 Larynx, 168. 
 
 Laughing, 176. 
 
 Legumes as food, 84. 
 
 Lemonade, 109. 
 
 Lemons, acid fruits, 87. 
 
 Levers, 253. 
 
 Liver, 90; description of, 200; hygiene 
 
 of, 208. 
 Lung capacity, 174. 
 Lungs, 1C7, 109. 
 Lymph and lymphatics, 147, 148. 
 
 Massage, 156. 
 
 Meat, as food, 87. 
 
 Menus, typical, plain, 88 ; typical, with 
 
 price, 124. 
 Milk, 78. 
 Molar teeth, 91. 
 Muscles, 251, 252; experiments, 255; 
 
 hygiene of, 255. 
 
 Narcotic drinks, general effect of, 65. 
 
 Narcotics, 58 ; effect of on respiration, 
 191 ; review of, 74. 
 
 Nerve, cells, 238, 239; centers, 240; 
 trunks, 240. 
 
 Nervous system, 46, 48, 50, 57, 237; 
 hygiene of, 245 ; influenced by alco- 
 hol, 246 ; review, 250. 
 
 Nucleolus t)f cell, 30. 
 
 Nutrition, defined, 76. 
 
 Oats, a cereal, 81. 
 
 Opium, 72. 
 
 Oranges, acid fruits, 87. 
 
 Organs, defined and described, 40 ; of 
 
 body, 27; of plant, 17; systems of, 
 
 42, 43. 
 Oxidation, defined, 15. 
 
 Pancreas (pan'kre-Ss) , 90, 95. 
 Pancreatic juice, digestion by, 101. 
 PapillsE, of skin, 212; tactile, 220; 
 
 vascular, 220. 
 Parotids {pn-rdl'ids) , 90. 
 Pharynx, 168. 
 Physiology, defined, 9, 10 ; general, 11; 
 
 special, begins, 75. 
 
INDEX 
 
 273 
 
 Plant, needs of, 11 ; parts of, 16 ; physi- 
 ology, 9, 11. 
 
 Plants, relation of, to animals, 26. 
 
 Plumule of plant, 20. 
 
 Problems ia domestic economy, 123, 
 125 ; in resplratlou, 190 ; on skeleton, 
 264. 
 
 Pfoteid, iodine test for, 21. 
 
 Protococcus, green dast plant, 33. 
 
 Protoplasm of plant, 17. 
 
 Pulse, 143. 
 
 Pylorus of stomach, 93. 
 
 Radicle of plant, 20. 
 
 Rectum, 90. 
 
 Reflex action, 52. 
 
 Residual air, 173. 
 
 Respiration, defined, 164, 165; exter- 
 nal, 166; hygiene of, 186; internal, 
 166 ; organs of, 166, 167; movements 
 of, 170 ; review, 193. 
 
 Respiratory system, 42. 
 
 Rest and exorci.se, 256 ; time for, 157. 
 
 Eice, a cereal, 81. 
 
 Rye, a cereal, 81. 
 
 Saliva, digestion by, 97. 
 
 Salivary glands, 90. 
 
 Seeing, sense of, 230. 
 
 Sensation, function of skin, 216. 
 
 Sensations, described, 54. 
 
 Sense, of hearing, 228 ; of position, 222 ; 
 of seeing, 230; ofsmell,226; of taste, 
 225 ; of temperature, 221 ; of touch, 
 220. 
 
 Senses, general and special, 220; re- 
 view of special, 236. 
 
 Sighing, 176. 
 
 Skeleton, 263, 266; affected by tight 
 clothing, 270; problems on, 264, 
 
 Skin, description of, 212 ; hygiene of, 
 216; organ of sensation, 219; review 
 of, 223. 
 
 Smell, sense of, 226. 
 
 Sneezing, 176. 
 
 Sobbing, 176. 
 
 Soda water, 109. 
 
 Speech, 177. 
 
 Spinal cord, 241, 242. 
 Spirits, ardent, 62. 
 Starch, iodine test for, 21. 
 Stentor, one-celled animal, 36. 
 Stomach, 89, 90, 93, 94. 
 Sublinguals (svb-lXn'gwals), 90. 
 Submaxilla,ries [siib-max'll-la-ries) , 
 
 90. 
 Sweat glands, 212. 
 Sympathetic nervous system, 51. 
 System, circulatory, 42; digestive, 42 ; 
 
 respiratory, 42. 
 
 Taste, sense of, 225. 
 
 Teeth, 91, 92. 
 
 Temperature, sense of, 221. 
 
 Tidal air, 172. 
 
 Tissue, defined, 39. 
 
 Tissues, active, 16 ; of body, 27 ; review 
 
 of, 45; supporting, 16. 
 Tobacco, 71 ; effects of, on heart, 161 ; 
 
 on brain work, 250; influence of, on 
 
 respiration, 193. 
 Touch, sense of, 220. 
 Trachea, 167. 
 
 Valves of veins, 139. 
 
 Vegetables, as food, 84; experiments 
 
 with, 86. 
 Veins, 139. 
 Vena cava, 140. 
 Ventilation, 187. 
 Vertebral column, 263, 264. 
 Villi of intestine, 95. 
 Villus, organ of absorption, 199. 
 Vocal cords, 168. 
 Voice, 175, 176. 
 Volnntary action, 52. 
 Vorticellai one-celled animal, 36. 
 
 Waste matter, how thrown out of body, 
 
 206. 
 Water, as drink, 107. 
 Wheat, a pereal, 81. 
 Windpipe, 167. 
 
 Yawning, 176. 
 
 Yeast plant, described, 59. 
 
 Typography by J. S. Cushing & Co., Norwood, Mass., U.S.A. 
 
Text- Books in Physical Training 
 
 BLAIKIE'S SOUND BODIES FOR OUR BOYS AND GIRLS 
 By William Blaikie, author of " How to Get Strong and 
 
 How to Stay So." Cloth, i6mo 40 cents 
 
 A manual of simple, practical exercises for the training and develop- 
 ment of the body so as to leave no muscle undeveloped. Numerous 
 illustrations are given to make the directions for the various exercises 
 clear and practical. The exercises are free from risk and can be easily 
 learned. They can be practiced in the schoolroom in the brief intervals 
 between the recitations under the eye and direction of the teacher without 
 any loss of time. While the pupils are making progress in their studies 
 they are at the same time building and strengthening their bodies and 
 by so doing secure both bodily vigor and sound health. 
 
 MORRIS'S PHYSICAL EDUCATION 
 
 By R. Anna Morris, Cloth, 8vo . . . . $1.00 
 
 A system of exercises including the Delsartean principles of execu- 
 tion and expression, for use in schools. Each exercise and drill 
 prescribed can be practiced in any school, and the few pieces of appa- 
 ratus suggested are simple and inexpensive. Part I describes general 
 positions and drills, and furnishes graded instruction for the development 
 for each part of the body. Part II treats of the subject of expression 
 as applied to reading, articulation, and declamation. Musical selections 
 are given to accompany the physical exercises, a°nd appropriate illustra- 
 tions are added to indicate the movements and positions described. 
 
 SMART'S MANUAL OF SCHOOL GYMNASTICS 
 
 By James H. Smart. Revised and Enlarged . 30 cents 
 
 Consisting of free gymnastics, dumb-bell exercises, and aesthetic 
 exhibition exercises, so planned as to develop every part of the 
 body. Movements are provided for standing positions, sitting positions, 
 breathing and vocal exercises, dumb-bell exercises, military movements, 
 and exhibition figures. The book is fully illustrated, and includes a 
 number of musical selections to accompany the gymnastic exercises. 
 
 Copies of any of the above books will be sent, prepaid, to any address 
 on receipt of the price by the Publishers: 
 
 American Book Company 
 
 New York ♦ Cincinnati . Chicago 
 
 (■53) 
 
STORER AND LINDSAY'S 
 
 Elementary Manual of Chemistry 
 
 By F. H. STORER, S.B., A.M., and W. B. LINDSAY, A.B., B.S. 
 Cloth, 12mo, 453 pages. Illustrated.- Price, $1.20 
 
 This work is the lineal descendant of the " Manual of 
 Inorganic Chemistry" of Eliot and Storer, and the " Ele- 
 mentary Manual of Chemistry " of Eliot, Storer and Nichols. 
 It is in fact the last named book thoroughly revised, 
 rewritten and enlarged to represent the present condition 
 of chemical knowledge and to meet the demands of American 
 teachers for a class book on Chemistry, at once scientific 
 in statement and clear in method. 
 
 The purpose of the book is to facilitate the study and 
 teaching of Chemistry by the experimental and inductive 
 method. It presents the leading facts and theories of the 
 science in such simple and concise manner that they can 
 be readily understood and applied by the student. The 
 book is equally valuable in the classroom and the laboratory. 
 The instructor will find in it the essentials of chemical 
 science developed in easy and appropriate sequence, its 
 facts and generalizations expressed accurately and scientifi- 
 cally as well as clearly, forcibly and efegantly. 
 
 " It is safe to say that no text-book 
 has exerted so wide an influence 
 on the study of chemistry in this 
 country as this worlc, originally 
 written by Eliot and Storer. Its 
 distinguished authors were leaders 
 in teaching Chemistry as a means 
 of mental training in general edu- 
 cation, and in organizing and per- 
 fecting a system of instructing 
 students in large classes by the 
 experimental method. As revised 
 and improved by Professor Nichols, 
 it continued to give the highest 
 satisfaction in our best schools and 
 colleges. After the death of Pro- 
 fessor Nichols, when it became 
 
 necessary to revise the work again. 
 Professor Lindsay, of Dickinson 
 College, was selected to assist Dr. 
 Storer in the work. The present 
 edition has been entirely rewritten 
 by them, following throughout the 
 same plan and arrangement of the 
 previous editions, which have been 
 so highly approved by a generation 
 of scholafs and teachers. 
 
 " If a book, like an individual, 
 has a history, certainly the record 
 of this one, covering a period of 
 nearly thirty years, is of the highest 
 and most honorable character." 
 — From The American Journal of 
 Science. 
 
 Copies ef this hook will be sent prepaid to any address^ on receipt o/ the price^ 
 by the Publishers : 
 
 American Book Company 
 
 New York ♦ Cincinnati ♦ Chicago 
 
 (i60 
 
Burnet's Zoology 
 
 FOR 
 
 HIGH SCHOOLS AND ACADEMIES 
 
 BY 
 
 MARGARETTA BURNET 
 
 Teacher of Zoology, Woodward High School, Cincinnati, O. 
 
 Cloth, 12mo, 216 pages. Illustrated. Price, 75 cents 
 
 This new text-book on Zoology is intended for classes 
 in High Schools, Academies, and other Secondary Schools. 
 While sufficiently elementary for beginners in the study it is 
 full and comprehensive enough for students pursuing a 
 regular course in the Natural Sciences. It has been prepared 
 by a practical teacher, and is the direct result of school-room 
 experience, field observation and laboratory practice. 
 
 The design of the book is to give a good general knowl- 
 edge of the subject of Zoology, to cultivate an interest in 
 nature study, and to encourage the pupil to observe and to 
 compare for himself and then to arrange and classify his 
 knowledge. Only typical or principal forms are described, 
 and in their description only such technical terms are used 
 as are necessary, and these are carefully defined. 
 
 Each subject is fully illustrated, the illustrations being 
 selected and arranged to aid the pupil ifi understanding the 
 structure of each form. 
 
 Copies of Burnet's School Zoology ■mill be sent prepaid to any address, 
 on receipt of the price, by the Publishers: 
 
 American Book Company 
 
 New York * Cincinnati • Chicago 
 
Biology and Zoology 
 
 DODGE'S INTRODUCTION TO ELEMENTARY PRACTICAL 
 BIOLOGY 
 
 A Laboratory Guide for High School and College Students. 
 By Charles Wright Dodge, M.S., Professor of Biology 
 
 in the University of Rochester $1 80 
 
 This is a manual for laboratory work rather than a 
 text-book of instruction. It is intended to develop in the 
 Student the power of independent investigation and to 
 teach him to observe correctly, to draw proper conclusions 
 from the facts observed, to express in writing or by means 
 of drawings the results obtained. The work consists 
 essentially of a series of questions and experiments on 
 the structure and physiology of common animals and 
 plants typical of their kind — questions which can be 
 answered only by actual investigation or by experiment. 
 Directions are given for the collection of specimens, for 
 their preservation, and for preparing them for examination; 
 also for performing simple physiological experiments. 
 
 ORTON'S COMPARATIVE ZOOLOGY, STRUCTURAL AND 
 SYSTEMATIC 
 
 By James Orton, A.M., Ph.D., late PrcSfessor of Natural 
 History in Vassar College. New Edition revised by 
 Charles Wright Dodge, M.S., Professor of Biology in 
 the University of Rochester . . .' . . . $1.80 
 This work is designed primarily as a manual of 
 instruction for use in higher schools and colleges. It 
 aims to present clearly the latest established facts and 
 principles of the science. Its distinctive character con- 
 sists in the treatment of the whole animal kingdom as a 
 unit and in the comparative study of the development and 
 variations of the different species, their organs, functions, 
 etc. The book has been thoroughly revised in the light 
 of the most recent phases of the science, and adapted to 
 the laboratory as well as to the literary method of teaching. 
 
 Copies of either of the above books -will be sent, prepaid, to any address 
 on receipt of the price, 
 
 American Book Company 
 
 New York • Cincinnati ♦ Chicago 
 
 (167) 
 
Gray's Series of Botanies 
 
 By the late Asa Gray, LL.D., of Harvard University 
 
 FOR ELEMENTARY AND GRAMMAR SCHOOLS 
 
 Gray's How Plants Grow. With a Popular Flora . • $0 80 
 
 A simple introduction to the study of Botany. 
 
 Gray's How Plants Behave. A Botany for Young People . -54 
 A primary book showing how plants move, climb, act, etc. 
 
 FOR SECONDARY SCHOOLS 
 
 Gray's Lessons in Botany. Revised edition . . • -94 
 
 Gray's Field, Forest, and Garden Botany. New edition, 
 
 containing Flora only ,...'••' -^^ 
 Gray's School and Field Book of Botany. Comprising the 
 
 "Lessons " and "Field, Forest, and Garden Botany," 1.80 
 A complete book for school use. 
 
 FOR COLLEGES AND ADVANCED STUDENTS 
 
 Gray's Manual of Botany. Revised, containing Flora only. 
 
 For the Northern United States, east-of the Missisippi, 1.62 
 The Same. Tourist's edition. Thin paper, flexible leather, 2.00 
 Gray's Lessons and Manual of Botany. One volume. Revised, 
 
 comprising the "Lessons in Botany" and the "Manual," 2.16 
 Gray's Botanical Text-Book 
 
 I. Gray's Structural Botany 2.00 
 
 II. Goodale's Physiological Botany . .... 2.00 
 
 FOR WESTERN STUDENTS 
 
 Coulter's Manual of the Botany of the Rocky Mountains . 1.62 
 Gray and Coulter's Text-Book of Western Botany. Com- 
 prising Gray's ' ' Lessons " and Coulter's ' ' Manual of 
 the Rocky Mountains" ••■... 2.16 
 
 Copies of any of the above books will be sent, prepaid, to any address 
 on receipt of the price by the Publishers : 
 
 American Book Company 
 
 NEW YORK . CINCINNATI ♦ CHICAGO 
 
 (171)