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AN 
 
 INQUIRY #& &»***,& 
 
 INTO THE 
 
 USE OF THE OMENTUM. 
 
 BY JAMES RUSH. 
 
 OF PHILADELPHIA. 
 
 PHILADELPHIA, 
 
 FROM THE PRESS OF T. fcs* G.-PALMER. 
 
 / 
 
 
 1809 . 
 

 
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AN 
 
 INAUGURAL DISSERTATION 
 
 FOR 
 
 The Degree of Doctor of Medicine . 
 
 SUBMITTED TO 
 
 ) 
 
 THE EXAMINATION OF THE 
 
 REV. JOHN M‘DOWEL, LL. D. PROVOST, 
 
 THE 
 
 TRUSTEES AND MEDICAL PROFESSORS 
 
 OF THE 
 
 University of Pennsylvania. 
 
 ON THE 19TH DAY OF APRIL, 1809 
 

 
 
 
 
 
 
 
 
 
 * 
 
 
 
 
 
 . 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
TO BENJAMIN RUSH, M. D 
 
 PROFESSOR OF THE INSTITUTES AND PRACTICE OF MEDI- 
 CINE, AND OF CLINICAL PRACTICE, IN THE UNIVERSITY 
 OF PENNSYLVANIA. 
 
 HONOURED SIR, 
 
 For favours which I can neither express nor 
 repay, I beg your acceptance, in this public manner, of 
 the acknowledgments of your affectionate and grateful 
 son and pupil, 
 
 JAMES RUSH, 
 

 
 
 
 
 
 
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ALSO TO 
 
 CASPAR WISTAR, M. D. 
 
 PROFESSOR OF ANATOMY ; 
 
 JAMES WOODHOUSE, M. D. 
 
 PROFESSOR OF CHEMISTRY ; 
 
 BENJAMIN SMITH BARTON, M. D. 
 
 PROFESSOR OF MATERIA MEDICA, NATURAL HISTORY, AND BOTANY , 
 AND TO 
 
 PHILIP SYNG PHYSICK, M. D. 
 
 AND 
 
 JOHN SYNG DORSEY, M. D. 
 
 UNITED PROFESSORS OF SURGERY, 
 
 IN THE UNIVERSITY OF PENNSYLVANIA, 
 
 AS A TESTIMONY OF GRATITUDE 
 FOR THEIR CIVILITIES, AND THE INSTRUCTION DERIVED FROM 
 THEIR LECTURES, 
 
 THE FOLLOWING DISSERTATION 
 
 IS INSCRIBED, 
 
 BY THEIR OBLIGED FRIEND AND PUPIL, 
 
 JAMES RUSH. 
 
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AN INQUIRY 
 
 INTO THE 
 
 USE OF THE OMENTUM. 
 
 N O VEL opinions in science, like the essays of infant 
 speech, are often faultering or false. Let it be considered, 
 however, that the faulter may become the tone of authori- 
 ty, and that error detected lessens the embarrassments of 
 truth. These reflections countenance the attempts of 
 theory, and encourage the adventurer with hope. It is 
 true, the period has been anticipated when observation 
 and books should have yielded their contribution to the 
 writer ; but the subject has been entered upon, from a 
 conviction that system in arrangement and method in 
 reasoning, give their advantages to the framer. He who 
 benefits an individual does a plausible duty, and such 
 is his beneficence, who renders a service to himself. 
 Truth lies hidden beneath the surface, and though 
 theory cannot always make the discovery, it may work 
 upon the spot of its concealment : a better occupation 
 surely than his, who indolently waits, vainly imagining 
 it will take root, and spring up under his feet. 
 
 B 
 
10 
 
 The theories or reasonings in physiology, and their 
 importance to practice, have been particularly the ob- 
 jects of cavil. Many of the functions of the human 
 body can be explained only by analogy ; as if nature, 
 for the comprehension of her noblest work, required 
 the exertion of man’s noblest faculty. The enemies of 
 physiology object not to its established, but to its un- 
 known doctrines. The practical utility of those alrea- 
 dy proved, are too obvious to admit of dispute. The 
 circulation of the blood, the process of digestion, and 
 the actions of the intestines, are truths, without the 
 knowledge of which even the empiric could scarcely 
 practise. These were the result of physiological re- 
 searches ; and were once as obscure as many things yet 
 to be discovered. This is my apology for considering 
 a speculative subject in physiology. 
 
 In the list of subjects for discussion, an inquiry into 
 the use of the omentum in the animal structure, has been 
 suggested by the doctrine of the office of sanguification, 
 lately, ascribed to the liver, by my father*. To this 
 function, he has also attributed the conversion of fat 
 into the matter of nourishment for the body. This 
 opinion I have embraced, and by its more particular 
 application to explain the intention of the omentum, 
 shall endeavour to treat it with more minuteness than 
 the author himself has devoted to it in his lectures. 
 
 '* See Medical Museum, Yol. Ill — Dr. Rush on the functions of 
 the liver, spleen, See. 
 
il 
 
 It would be tedious to consider, at length, the struc- 
 ture and other anatomical circumstances of the omen- 
 tum. It will be sufficient to observe, that it is a pen- 
 dulous membranous body, folded so as to form a cavity 
 resembling a sack ; attached to the stomach by its ante- 
 rior, and to the colon by its posterior fold ; hanging 
 between the anterior parietes of the abdomen and in- 
 testines ; extending commonly as low as the umbili- 
 cus. It consists of two thin membranes, united by 
 cellular substance, and ia well supplied with blood- 
 vessels. The cellular substance uniting these two 
 membranes is the seat of the fat, which is the more im- 
 mediate object of this essay. 
 
 The uses ascribed to the omentum have been many 
 and various ; some of those generally received shall be 
 the objects of consideration. 
 
 I. Its office has been supposed to prevent the injuries 
 from the friction of the intestines upon each other, by 
 furnishing an oleaginous fluid to lubricate them. 
 
 It has long been the practice of physiologists, to 
 measure the intentions of nature by their own ingenu- 
 ity. Hence the explanations of the pulsations of the 
 heart ; of the equilibrium given to the body by the 
 spleen ; and of the lubricating quality of the omentum. 
 I object to this opinion, first, because it is too mechani- 
 cal. Although, strictly considered, every natural opera- 
 tion must be mechanical, yet physiology has often suf- 
 fered from a confusion of the attenuated laws of vital 
 action, with the grosser rules of the arts or mechanism 
 
12 
 
 of common life. Secondly, it is not necessary . We 
 know that moisture alone, is sufficient to give facility 
 of motion to parts pliant and polished ; now the in- 
 testines are under these circumstances, with regard to 
 themselves, and the peritoneum. Thirdly, by its fat 
 it cannot lubricate the intestines . The omentum is 
 not a fat-secreting surface, but a fat-containing cavi- 
 ty : its surface affording nothing except that moisture 
 which is natural to all internal membranes, and this 
 I have spoken of as abundantly supplied without the 
 aid of the omentum. Fourthly, the supposition that 
 it is to prevent friction , only substitutes, for attrition, 
 a substance less regular and yielding than the peritone- 
 um it is intended to cover. 
 
 II. A second use which has been ascribed to the 
 omentum is, that it is intended, with other abdominal 
 viscera, to prepare blood for the formation of bile. 
 Here, from an accidental, and at the same time an un- 
 avoidable circumstance, is deduced a conclusion not 
 warranted by any proof : accidental, as the liver was 
 placed in the cavity of the abdomen, and unavoidable , 
 as it could receive its blood from the viscera of no 
 other part. If we infer from this situation of the liver, 
 that a change takes place in the blood of the vena por- 
 tarum, this change must be produced by each particu- 
 lar viscus, or it must be the joint operation of all. It 
 cannot be the former, for each of the several parts se- 
 creting a different substance from the blood, must give 
 a different quality of blood to be returned. If it be the 
 
13 
 
 latter, disease in those parts must prevent the formation 
 of the peculiar hepatic blood. Let it not be said, that 
 disease or obstruction of these preparing viscera is 
 often attended or followed by fatal consequences to the 
 system. To this it may be answered, that these parts 
 are vital in other respects than their relation to the cir- 
 culation of the blood. Moreover, if the bile require 
 this oily secretion, why is the fat thrown out into cells ? 
 It ought to pass directly on to the liver through the 
 veins ; as this is not its course, it can get there only- 
 through the medium of the absorbents. To suppose it 
 first secreted, effused into cavities, and afterwards taken 
 up by lymphatics, is to admit a prolix, where nature has 
 a more simple process. 
 
 This opinion is grounded upon the fact, of fat being 
 found in the omental branches of the vena portarum ; 
 and from this has been explained the oily nature of the 
 bile. The inference from this fact is, that the liver 
 is not a secretory organ, but a filter. It is impos- 
 sible however that acini so minute as to prevent the 
 passage of blood, should give admission to so viscid 
 a substance as fat, of such a size as to be the object of 
 examination by the eye. The bile does not derive its 
 oily nature from the fat ; we have seen that it cannot 
 pass by filtration, it must undergo the secretory ac- 
 tion. Now the very essence of secretion is an altera- 
 tion of chemical properties, which if the fat suffer, it 
 cannot form the oil of the bile, for, take the most 
 minute portion of its principles away, and you destroy 
 its nature as fat. 
 
14 
 
 III. A third opinion advocated for the use of this vis- 
 cus, is that it serves to keep the intestines warm. If this 
 should need a refutation, I would observe : First, it 
 will apply only to hybernating animals. In their living 
 state, nature has prevented the evil arising from a de- 
 fect of warmth, by placing these viscera near the great- 
 est source of heat. Secondly, if it were true, die 
 want of such a provision would be felt elsew here. 
 Why has not the brain its hood, or why is the thorax 
 without its breast- plate ? 
 
 This opinion is deduced from the fact, that very fat 
 people feel the cold less sensibly than those who are 
 lean. But this is to be ascribed to the effect it has 
 upon the nerves. Richerand, in speaking of the uses 
 of the fat, says, “ and finally, it covers and surrounds 
 the extremities of the nerves, diminishing their suscep- 
 tibility, which is always in an inverse proportion to cor- 
 pulency .” Again, “ In fact, persons subject to nervous 
 affections, constantly join an extreme leanness to an ex- 
 cessive sensibility 
 
 Other opinions of the uses of this organ have been 
 proposed. They will be omitted to give place to one, 
 to the support of which the following pages shall be 
 devoted. 
 
 I shall endeavour to prove the omentum to be an or- 
 gan for the secretion of fat , furnished with vesicula for 
 its reception , in order to supply the body with nourish- 
 ment , when the resources by the stomach fail. 
 
 * Physiology. Article Ixxvi. 
 
15 
 
 The arguments for the support of this proposition 
 will be deferred, till the consideration of some circum- 
 stances which are connected with this view of the sub- 
 ject. 
 
 That fat nourishes the body in certain states is no 
 new idea ; the phenomena of its existence were too ob- 
 vious not to lead to that conclusion. As an old doc- 
 trine, it has little meaning. Blood is the only medium 
 of nourishment with which we are acquainted ; but the 
 fat has not yet become blood. How is this effected ? 
 It may be said that it is produced by the lymphatics 
 and their glandular system. This may be answer- 
 ed, by observing, First, whatever change is the effect 
 of their action, it is certain they do not completely con- 
 vert it into blood ; nay, they do not even form a chylous 
 substance, but a more limpid fluid. Secondly, fat has 
 been found in the branches of the vena portarum. A 
 sufficient proof that it has passed, with little or no alter- 
 ation, the action of the lymphatics : it being immaterial 
 whether it has gotten into the veins by a set of partial 
 vessels, or has passed the circle of the general absor- 
 bent system. The change then must be made after it 
 enters the circulation, and nowhere is there a cause ade- 
 quate to that, except in the lungs or the liver. It can- 
 not be in the lungs, for chyle has been found in the 
 blood after it has passed through them. 
 
 It remains then for the liver to perform the office in 
 question, and this I shall now consider more in de- 
 tail. 
 
16 
 
 “ The design of the liver,” says the author, in the 
 essay referred to, “I believe to be, to receive the blood 
 from every part of the body, in order to subject that 
 part of it which has not been completely animalized, 
 or divested of its chylous properties, to a secretory 
 process, and afterwards to pour the product of this 
 secretion, mixed with the liquor of the pancreas, into 
 the duodenum, to be absorbed or otherwise taken up 
 by the lacteals, and conveyed with the chyle from the 
 stomach iiiio the bloocl-vessels, in order to be com- 
 pletely converted into red blood, for the purpose of 
 serving the various and important uses for which that 
 fluid is intended in the human body.” It would con- 
 sume too much time to give, at large, the facts and rea- 
 sonings used by the author to support this proposition. 
 I shall give an abstract of them. The same power that 
 perfects the chyle, converts the fat to a like matter ; and 
 as this is one of the ideas embraced by this essay, its 
 proof may be required. 
 
 The arguments in support of this doctrine are, 
 
 “ 1st. The presence of the liver, in nearly all ani- 
 mals, being in this respect on a footing with the sto- 
 mach.” 
 
 “ 2d. The immense and disproportionate size of 
 the liver in the foetus, compared with that of the adult, 
 the design of which appears to be, that nourishment 
 may be carried on exclusively by that viscus, without 
 any aid from the stomach.” 
 
17 
 
 £t 3d. The size of the liver in adults, and 4he quan- 
 tity of bile secreted, said by Haller to be twenty -four 
 ounces in 24 hours.” 
 
 “ 4th. Chyle has been found in the blood after it 
 has passed through the lungs ; hence it requires another 
 process.” 
 
 “ 5th. The quality of the venous blood from which 
 the bile is secreted. It is less disposed to putrefaction 
 than arterial blood in any part of the body. This arises 
 from the chyle it contains, as chyle is less putrescent 
 than blood.” 
 
 “ 6th. The quality of hepatic bile, it being sweet. 
 Haller says, “dulcior hepatica cystica arnara. ” 
 
 “ 7th. Sever 4 experiments of Dr. Fordyee prove 
 chyle to be formed by the action of saliva and gastric 
 juice upon the aliment, without the mixture of hepatic 
 bile.” 
 
 “ 8th. The structure, situation, and function ot the 
 pancreas. It resembles the salivary giands in its struc- 
 ture ; it secretes a liquor which possesses the same dis- 
 solving and animalizing properties as the saliva ; and it 
 pours this liquor so directly upon the hepatic bile, as to 
 change it into perfect chyle.” 
 
 “ 9th. It is inferred that a second chylopoietic pro- 
 cess goes on in the liver, from the effects of intempe- 
 rance upon it. It increases its labour, and thereby in- 
 creases its size.” 
 
 To the above arguments in support of this opinion 
 of the function of the liver, I shall add the foil on ing ob- 
 servations. Doctor Pemberton, in his treatise upon the 
 
 c 
 
18 
 
 diseases of the viscera*, has taken a view of the glands 
 of the body, as divided into those that secrete a fluid 
 from the blood for the use of the system, and those that 
 secrete a fluid to be discharged from it. The former 
 he has called glands of supply ; the latter, glands of 
 waste. He has satisfactorily shown, that derangements 
 of the glands of waste are not attended by any altera- 
 tion ill the bulk of the body ; whereas disease in the 
 glands of supply, in almost every case, produces emaci- 
 ation. The liver is an organ, the diseases and disorders 
 of which cause a wasting of the flesh. This gives it a 
 place among the glands of supply. I would however 
 infer that it serves this purpose, more than is generally 
 allowed ; for if so great a quantity of bile as 24 ounces, 
 which is secreted in 24 hours, be not excrementitious, 
 how considerable must its effect be in nourishing the 
 body ! It is known that gall-stones obstructing the 
 biliary ducts produce emaciation. This has been as- 
 cribed to the effect of the irritation of pain upon the 
 system. I would rather suppose it to be owing to the 
 obstruction to the flow of bile, when the stone is in the 
 ductus communis ; and when it is in the cystic duct, 
 to the irritation, by continuous sympathy, causing a 
 vitiated secretion of bile. 
 
 With these views of the liver as established premi- 
 ses, I shall proceed to exhibit the proofs of the proposi- 
 
 * See “A Practical Treatise on Various Diseases of the Abdo- 
 minal Viscera,” by C. R, Pemberton. 
 
19 
 
 tion laid down, on the subject of the intention of the 
 omentum. 
 
 This viscus seems not to be one of those whose use 
 is inscribed upon it so legibly, as not to need the efforts 
 of reason to decypher it. The appearance it exhibits 
 to the eye, is not sufficient to manifest its operations. It 
 is of such inconsiderable importance to the animal sys- 
 tem, as not to give by its own derangements any very 
 sensible alteration to the functions of the body, or at 
 any rate it has its office vicariously supplied. From 
 this view we may see why the separation of parts of it, 
 its adhesions, and every other preternatural state of it, 
 have so little effect upon the body. Hence too the dif- 
 culty and inefficacy of any experiments, to which it could 
 be subjected. There exist, however, facts enough con- 
 nected with its ordinary phenomena, as exhibited after 
 disease, to afford just conclusions of its use. To this 
 add its fitness for the office here ascribed to it. For 
 though the sufficiency of a cause be not an undeniable 
 argument for its agency, yet it is essential to proof. 
 
 It has been said before, that the omentum is an organ 
 for the secretion of fat , furnished with cells for its re- 
 ception. This is true, whatever be the intention of the 
 fat when secreted. It is true, because it is seen. I 
 know of no other argument for its proof. Beside 
 the evidence of our senses, proof requires the media- 
 tion of axioms. There is no assertion more self-evi- 
 dent. I might indeed vary its form, but, like the revo- 
 
lutions of a sphere, it would not bring a greater com 
 pass into view*. 
 
 The second part of the proposition to be considered 
 is, that the omentum is intended for the purpose of sup- 
 plying the body with nourishment when the resources by 
 the stomach fad. My behei in this arises from the 
 following <ic 
 
 1st. From the situation of the omentum, being in that 
 part of the bod} where it can afford none of those offi- 
 ces, which the fat in other paita of the system supplies. 
 These are, giving shape to the body, lubricating for the 
 advantages of motion, filling up unavoidable cavities, 
 and serving as the envelope of some viscus or organ. 
 Here is no rugged angle of feature to be smoothed. 
 Here is no eye whose delicateness the contact of bone 
 would injure. 
 
 2d. From its little sensibility , known from the re- 
 moval of parts of it, and from its circumstances in hernia 
 and wounds. From this I would infer an aptitude for 
 its intention to admit of variation in its size by its dis- 
 tention with fat : a property which, had it not pos- 
 sessed, w ould have subjected it to the inconveniences 
 of pain. 
 
 3d. From its presence in so many animals, taken in 
 conjunction with 
 
 4th. Its absence in others. It w ould be tedious to 
 enumerate the different animals in which this viscus is 
 found, as well as those in whom it is wanting. The 
 
 * Perhaps we might urge its great vascularity, and its diseases, 
 hydatids and sehirrus, in favour of its being a secretory organ 
 
21 
 
 exceptions to it, give the best idea of its use. For 
 here, as in the forms of mathematical evidence, the 
 substitution is more easily understood. When the 
 omentum is wanting, its place is supplied by a substance 
 which allows scarcely a doubt of its use, and to ascribe 
 to that substance the generally received uses of the 
 omentum, would be absurd. There is only one office, 
 which these adipose substances appear capable of afford- 
 ing, and that is, the nourishment of the body by their 
 fat. This, indeed, is universally allowed. Haller, 
 speaking of the use of the omentum, says: “ Qua ta- 
 
 men animalia omento destituunter, iis adipis massa pro 
 omento est ; avibus nempe aquaticis aliisque et pisci- 
 bus*.” But without the argument arising from this 
 circumstance, even were this substitute wanting, still 
 its absence would not be an unanswerable objection. 
 The qualities that animals possess are variously, but 
 not partially bestowed. Hence the want of one is sup- 
 plied by the presence of another similar to it, or equally 
 important. If the omentum should be wanting in some 
 animals, this would not prove that they were denied the 
 advantages that others received from it, or that it was 
 useless in those that had it. It would be explained by 
 these three circumstances : first, that the animals had 
 other peculiarities of structure, as important; secondly, 
 that fat was to them not so necessary ; or, thirdly, that 
 the existence of this fat would be inconsistent with 
 some other property more advantageous to the animal. 
 
 Elementa Phys, vol. vi, p, 381. 
 
22 
 
 5th. I infer the use I have ascribed to this viscus 
 from the state of the omentum in hybernating animals . 
 Besides the quantity of fat throughout the cellu- 
 lar membrane generally, and an omentum much dis- 
 tended with it, these animals have two lateral appendices, 
 like the omentum in their structure and intention. 
 Haller speaks of this appearance in some of these ani- 
 mals, “ ut sint tria quasi omentaf.” Now, what is 
 the occasion of this great provision ? The only circum- 
 stance that distinguishes these animals from others, is 
 their remaining, for a certain time, without the resour- 
 ces of the stomach for food. Corresponding to this is 
 the state of the omentum. There is no other peculi- 
 arity of these animals that requires this difference. 
 There is not more need for lubrication, not more oil 
 required for the bile, nor is it necessary for any other 
 of the imaginary uses ever ascribed to the omentum. 
 
 The views arising from this class of animals are so 
 interesting to the subject, that they will be considered 
 more fully. 
 
 Cuvier, in his observations on this subject, mentions 
 a fact, which, by indicating a use for the omentum, 
 seems to be an objection to that one I wish to establish. 
 “ Le grand epiploon , suspendu comme un rideau entre 
 les parois musculeuses du bas-ventre, et les circonvo- 
 lutions des intestins, modere sans doute un peu les 
 froissemens que ceux-ci pourroient eprouver des pre- 
 
 * Haller’s Physiology, vol. vi, p. 381. 
 
23 
 
 mieres, et sert particulierement a retenir dans les intes- 
 tins la chaleur qui tend continueHement a s’echapper 
 vers la circonference. L’histoire des membranes grais- 
 seuses dans les animaux qui hibernent, va nous con- 
 firmer dans cette derniere opinion. Lorsque l’estomac 
 est plein d’alimens, cet epiploon est raccourci et releve 
 sur sa face anterieure, de maniere a la recouvrir plus 
 completement qu’avant. II rend alors plus particu- 
 lierement a ce viscere le service que nous venons de 
 lui attribuer a l’egard des intestins. En meme temps 
 le sang passant moins facilement dans ces vaisseaux, 
 coule plus abandomment dans ceux de l’estomac, dont 
 les premiers ne sont que des divisions, et y separe une 
 plus grande abondance des sues gastriques*.” 
 
 What seems to be of importance here is, that the 
 omentum is found investing the stomach, whilst it is 
 employed in digestion. A little inquiry will give this 
 an explanation. Observations on animals with the sto- 
 mach thus enveloped, have been made when the animal 
 was in its living state, well supplied with aliment from 
 the food it was taking, and before the store of fat was laid 
 up for its winter support. Now, that a membrane, 
 thin and vacillating, should, by the constant peristaltic 
 motion of the intestines, be contorted from its natural de- 
 pendent situation, is not extraordinary, but purely acci- 
 dental and natural. Before the action of the stomach 
 has ceased to be required, the wants of the animal have 
 
 * Lecon xxii, p. 86. 
 
2 4 
 
 called for an accumulation of fat. When the cells of 
 the omentum have become distended, the most econo- 
 mical situation for this membrane is extended and flat. 
 Hence it leaves the stomach, and is spread upon the in- 
 testines. But why, according to Cuvier’s idea, does 
 this change take place ? The bowels are not more ac- 
 tive than the stomach ; nor is there any other reason 
 why they require more warmth. The last part of this 
 quotation supposes that another advantage is given to 
 the stomach, by this folding of the omentum causing 
 a greater secretion of gastric liquor. This is not the 
 only viscus to which this office of supplying blood to 
 the stomach, has been ascribed. The spleen is even 
 yet supposed to be for that purpose. They are both 
 equally untrue. The greater flux alone of blood in any 
 viscus, never tends to increase its secretions. This is 
 proved by the phenomena of the circulation and of fe- 
 vers. Exercise is not, when violent, immediately fol- 
 lowed by an increase of all the secretions; nor are in- 
 flammations of the liver and kidneys always attended by 
 a preternatural flow of bile or urine. An unusual 
 quantity of blood, in any part, produces disease, or is 
 disease itself. It would be well, if, by secretion, an 
 organ could thus easily rid itself of its irritating cause. 
 Celerity or energy of chemical attractions alone, can 
 give rapidity to secretion. 
 
 Some of the species of the hybernating animals arc 
 destitute of the omentum. The account given of such 
 animals will sufficiently obviate any objection that 
 might arise from it. Cuvier, in speaking of the hy- 
 
25 
 
 foernating class, says, “ Les oiseaux des mceurs analo- 
 gue, tels que l’hirondelle de marais, plusieurs reptiles 
 que hibernent de meme sont depourvus aussi de ces 
 membranes graisseuses ; il est vrai que leur peritoine 
 se charge pendant l’hiver frune graisse abondante .” 
 
 6th. From the defect of fat in the omentum of the 
 foetus. “ Tenue in fetu, in adulto homine varie obe- 
 sum*.” This is a fact of great importance. In the 
 foetal state the supply of nourishment is nearly uniform. 
 The minute arterial connection of the placenta with the 
 uterus, prevents the effects of a hurried or disordered 
 circulation upon the foetus. Hence there is but little 
 alteration of the volume of blood sent to it, under every 
 irregularity of the mother. With such a constant and 
 unvaried supply, the office of the omentum in the foetus 
 would have been unnecessary. Soon after birth the fat 
 is deposited, for' then the want of it begins to be felt. 
 
 7th. I infer it, from its distention with fat more parti- 
 cularly than any part of the body, in those disposed to 
 obesity. Whatever purpose the fat serves, that must be 
 more eminently in view in the omentum, as it contains the 
 greatest quantity. It has been shown that its offices in 
 other parts of the body have no concern here. Its 
 more obvious and important intention of serving as 
 nourishment, alone remains of its uses. 
 
 8th. From its state when divested of fat ; being redu- 
 ced to a slender contracted membrane, and so much di- 
 minished, as to be apparently not fitted for any purpose 
 
 * Elementa Phys. vol. vi, page 367. 
 
 T) 
 
26 
 
 in the animal economy. The histories of dissections 
 contain many accounts of a partial or total loss of this 
 viscus. Of these I shall mention one, as quoted by 
 Portal, in the case of a patient who had died of pulmo 
 ry consumption. “ The other viscera were flaccid, 
 pale, and void of blood. The omentum was destroyed , 
 and the body reduced to such a degree of emaciation, as 
 to resemble a very skeleton*.” Here it was not destroy 
 ed, as parts of the body often are, by local disease, nor 
 was it absorbed, as parts are when removed from their 
 natural situation. But in a phthisical subject, where 
 the cause of the death was seated in the lungs, its dis- 
 appearance could have arisen only from the great de- 
 mand for nourishment, which attends this lingering dis- 
 ease. Not only in this case was the fat absorbed, but 
 its whole substance, as if the membranes, when they 
 had lost their contents, being useless, were themselves 
 taken for food. Perhaps the ludicrous observation 
 made by Mr. Bell, of the impossibility of lymphatics 
 absorbing themselves, might be urged here. I cannot, 
 however, see any more error in it, than in the intus- 
 susceptio and sphacelation of an intestine. But, even 
 admitting the impossibility of this, certainly one lym- 
 phatic may absorb another. It will be no objection to 
 this to say, that, whilst the vessel is in a living state, it 
 cannot be subject to the laws of inorganized matter. 
 In reality I know no difference between the laws ol 
 
 * Observations snr la Nature et sur le Traitement de la Phthise 
 Pulvnonaire, par Antoine Portal. Page 227. 
 
27 
 
 living and of lifeless matter ; but, according to either 
 idea, the invisible particles, which are taken up by the 
 absorbents, have not the property which common obser- 
 vation makes the characteristic of life, that is, organi- 
 zation or vascularity. 
 
 9th. From the structure of the omentum. It is vas- 
 cular for the secretion, and cellular for the reception of 
 fat, and is provided with lymphatics for its removal. 
 
 10th. Lastly, I infer that the intention of the omentum 
 is to afford nourishment to the body, from the connec- 
 tion of certain states of this viscus with the diseases of 
 the liver. The fat of the body, without a liver to 
 change it, would have been useless as to its most im- 
 portant property. The diseases of the latter might be 
 supposed to have an influence upon the former, and ac- 
 cordingly a diseased liver has been found, in many in- 
 stances, to be accompanied by an unnatural state of the 
 omentum. In some cases where, it is true, this vis- 
 cus should have been deprived of fat, it has been 
 found preternaturally distended with it. But, for- 
 tunately for my argument, the liver has, in these cases, 
 been also diseased. I admit, it may be shown from the 
 accounts of dissections, that the liver has been disordered, 
 and yet the fat of the omentum properly absorbed ; nay, 
 the membranes which inclose it have been destroyed. 
 This I shall answer by observing, first, that a diseased 
 appearance in the substance of the liver, does not prove 
 a derangement of its secreting organs ; and, secondly, 
 admitting this, much more knowledge on the sub- 
 ject is required to determine that these alterations did 
 
28 
 
 not take place before the liver became thus diseased. 
 It is sufficient, then, if I can give one or two instances 
 of this correspondence in disease, in the two viscera ; 
 the exceptions are explained by the two foregoing ob- 
 servations. 
 
 Lieutaud mentions some cases of this kind. I shall 
 relate one of them. In his observation 227, he says, 
 “ Quidam consistensibus eetatis obesus, et jam dudum 
 asthmaticus ; tandem in ischuriam lethalem incidit. 
 Secto cadavere, deprehenditur omcntem, ob majorem 
 adipis copiam ; et pondo trigenti librarum. Hepar 
 or at mole maximum .” 
 
 In Heister’s observations* is related the case of a pa- 
 tient who died of extreme emaciation generally, but in 
 whom the omentum was found “ very fat.” He had 
 before death been long troubled with a diarrhoea, which 
 indeed indicated a disease of the liver, and the dissection 
 proved that viscus to be in a morbid state. But what was 
 of much more importance, as it proved the secretion of 
 that organ to be altered, was that the patient, during his 
 illness, was troubled with eructations of matter resem- 
 bling “ bile in being acrid, but destitute of its bitter or 
 acid taste.” 
 
 Here was a case, where, from the wasting diarrhoea 
 that attended, no fat would have been expected to be 
 found in the body ; and yet here, is an omentum loaded 
 with it. The liver was diseased, and incapable of con- 
 verting the fat to nourishment. In this state, then, 
 there was no need of absorption, and consequently we 
 
 * Observation ccclxxxii. 
 
29 
 
 find none. It may be said, that, as it had disappeared 
 from the other parts of the body, may not some other 
 cause than the disease of the liver have been the reason 
 why it also was not taken up ? This I would answer 
 by observing, first, that the fat of the other parts of the 
 body being less in quantity than in the omentum, would 
 be much sooner absorbed, and this may have taken 
 place before the liver was so far deranged as to be in- 
 capable of the office of chylification ; or, secondly, if 
 it shows the agency of any other cause, it is that the 
 lymphatics of the omentum and the other parts of the 
 body have different degrees of power ; a fact that would 
 turn to my advantage ; for, if the fat in the two situa- 
 tions have different intentions, we should expect to find 
 some of their other circumstances different. 
 
 Mr. Proust, in his Dissections*, relates a case that 
 helps to illustrate this question. A patient, who had 
 been much troubled with bilious complaints, was seized 
 with indigestion and vomiting; and these were suc- 
 ceeded by a diarrhoea, of which, after three weeks’ con- 
 tinuance, he died. On opening the body, much fat 
 was found everywhere, and the omentum “ entirely 
 occupied by it.” The liver was of a remarkable size . 
 Now, if any thing could have given rise to an absorp- 
 tion, it would have been the wasting of a diarrhoea, 
 and the want of nourishment which a diseased stomach 
 must have occasioned. Yet here is a body “ embon- 
 point asset f to use his own words. 
 
 * Observation xxv. 
 
30 
 
 The pulmonary consumption, more than any other 
 disease, is attended by an emaciation, arising, most 
 probably, from the chronic nature of that complaint. 
 It is certain that the proper and natural supply of ma- 
 terials for the action of any viscus are necessary for its 
 health. Perhaps, then, the diseases of the liver that 
 attend upon consumption, arise from its want of the 
 proper substance for its action. Perhaps, too, the want 
 of that natural supply gives rise to a vitiated secretion, 
 which may be the cause of the wasting diarrhoea that 
 commonly terminates that disease. 
 
 Concerning the disappearance of fat by disease, it 
 deserves to be remarked, that by fasting the action of 
 the lymphatics is increased. If it were not so, fat 
 could not be removed. Now, we know that the want 
 of food by the stomach, almost always causes an ab- 
 sorption of fat*. 
 
 • * Perhaps, under this remark, it might not be amiss to notice 
 the practical benefit to be derived from this disposition of the 
 lymphatics to take on a preternatural action during fasting. It 
 teaches us to endeavour, by abstinence, to promote the absorption 
 of collections of water in dropsy. That it should not oftener suc- 
 ceed, is owing to the interference of some cause that continues the 
 disease. If the removal of water were the only obstacle to the 
 cure of dropsy, I have no doubt that abstinence would, in almost 
 every case, be effectual. There are many instances on record ol 
 the advantage of this remedy. I shall relate one from Sir John 
 Hawkins’s Life of Dr. Johnson. 
 
 “ A few days after,” says sir John, “ he (Dr. Johnson) sent for 
 me, and informed me, that he had discovered in himself the syrup* 
 toms of a dropsy, and, indeed, his very much increased bulk, and 
 
31 
 
 I have thus gone through the several heads of the 
 reasons for my belief on this subject. If any one or 
 two of them appear not conclusive, or even objection- 
 able, let it be remembered that the evidence does not 
 rest upon them alone. If the whole, taken together, 
 should amount to proof, it is sufficient. 
 
 There remain yet some facts, connected with the 
 subject, which, not being referrible to any of the fore- 
 going heads, may properly be considered here. 
 
 It is said that the omentum of herbivorous animals 
 is in general more fat than that of carnivorous. It is 
 also said that the same peculiarity distinguishes those 
 whose motions are sluggish, from those whose habits 
 
 the swollen appearance of his legs, seemed to indicate no less. It 
 was on Thursday that I had this conversation with him ; in the 
 course thereof he declared, that he intended to devote the whole of 
 the next day to fasting , humiliation, and such other devotional 
 exercises as became a man in his situation. On the Sunday fol- 
 lowing I made him a visit, and, upon entering his room, I observed 
 in his countenance such a serenity, as indicated that some remark- 
 able crisis of his disease had produced a change in his feelings. 
 He told me, that, pursuant to the resolution he had mentioned to 
 me, he had spent the preceding day in an abstraction from all 
 worldly concerns; that, to prevent interruption, he had in the 
 morning ordered Frank (his servant) not to admit any one to him, 
 and, the better to enforce his charge, had added these awful words, 
 for your master is preparing himself to die. He then mentioned 
 to me, that, in the course of this exercise, he found himself re- 
 lieved from the disease which had been growing upon him, and 
 was becoming very oppressive, viz. the dropsy , by the gradual 
 evacuation of water, to the amount of twenty pints; a like instance 
 whereof he had never before experienced.” 
 
32 
 
 of life are more active. One answer will be sufficient 
 for both these facts. Nature, in the formation of ani- 
 mal bodies, has never made qualities to oppose each 
 other. Fat may have been very necessary for the nou- 
 rishment of those animals whose wants required physi- 
 cal alertness ; yet the existence of fat would have been 
 inconsistent with this last quality. A more important 
 function would hardly have been made subservient to 
 one less necessary. The fatness of herbivorous animals 
 is owing to the abundance of their food, not requiring 
 much exertion to obtain it. The herbivorous are fat, 
 because they require not activity. Carnivorous are 
 lean, because fat would have been an incumbrance. 
 
 Another fact to be referred to this division of the 
 subject, is the fat found in the abdomen of horses. 
 “ Equis a concusso per magnos motus omento adi- 
 pem non in venas redire, sed in abdominis caveam 
 quasi fusum elabi, et intestinis circumfundi*.” 
 
 It has been said before, that the omentum is a secre- 
 tory organ. In this case, the fat is secreted in a pre- 
 ternatural quantity, to such a degree, indeed, that the 
 cells of the membrane cannot contain it. Hence they 
 are ruptured, and it is poured into the abdomen. The 
 idea, that there is a greater quantity of fat, is corroborated 
 by the circumstance of its being altered in quality. It is 
 found “ quasi fusum,” which, plainly shows its secre- 
 tion to be changed : fat, in its natural state, never has 
 
 Haller’s Elementa Phys. vol. vi, p. 384. 
 
33 
 
 that form. Why violent exercise should give rise to 
 this preternatural secretion, I cannot pretend to say. 
 
 Some notice has before been taken of the unequal 
 quantities of fat in different parts of the body. Collec- 
 tions of it are often found about the heart, and in the 
 extremities, whilst other parts are much emaciated. 
 As the removal of the fat is performed by the absorb- 
 ents, it must be influenced by any irregularities that 
 may occur in that system. In addition, then, to the 
 reasons that have already been given for the partial 
 remains of fat, I shall observe that the lymphatic, like 
 every other system in the body, may be partially dis- 
 eased. Hence a preternatural activity of one part will 
 cause a speedy removal, whilst a torpor in another will 
 prevent any absorption of the fat. 
 
 Another fact, which goes not so much to support the 
 main object of this essay, as to prove the nutrient pro- 
 perty of the fat, and its use in the body, is the circum- 
 stances of those persons who are under the effects of fa- 
 mine. Dumas, speaking of long-continued abstinence, 
 says, “It is worthy of remark, that the examples of 
 this kind have principally women for their object.” 
 Now, it is a fact confirmed by anatomists, that fat is 
 proportionally more abundant in children and females. 
 
 I have thus in a cursory manner considered some 
 of the leading points of this subject. It has been more 
 my wish to establish a new opinion, than to enter mi- 
 nutely into circumstances already ascertained; although, 
 for the purpose of the former, much of the latter has 
 been necessary. Many facts and opinions have been 
 
 E 
 
34 
 
 omitted, which time would not allow, and which the 
 occasion of my writing forbids me to mention. To 
 have considered the subject in all its connections would 
 have been to extend it to too much length. The unity 
 of nature has forbidden a separation of different scien- 
 ces ; much less can a line be drawn through those sub- 
 divisions which have been designated by the names of 
 particular sciences. 
 
 Thus far the subject has been considered in relation 
 to theory. The speculative part of every science is its 
 shadow only. We meet it first, because the light is 
 placed behind it. I shall take leave of it by consider- 
 ing a few of the practical applications of the subject. 
 
 The first inference that presents itself, from the doc- 
 trine I have delivered, is an argument for copious and 
 protracted blood-letting. “ In an adult man,” says Ri- 
 cherand, “ of moderate rotundity, the adeps constitutes a 
 twentieth part of the weight of the body*.” This, upon 
 a moderate computation, would give seven pounds of fat 
 for the supply of the body ; a quantity sufficient for its 
 nourishment a considerable time. That it should not sus- 
 tain it as long as the same quantity of aliment taken by the 
 stomach should not surprise us, for some of the effects 
 of famine are to be considered as arising, not from the 
 want of additions to the body, but from the derange- 
 ments which the system suffers through the medium 
 of the stomach. The proper state of this viscus is 
 necessary to the health of the whole body. When the 
 
 * Ricberand’s Physiology, article lxxv. 
 
35 
 
 absence of its natural secretion causes disease there, no 
 wonder that the evil of famine is doubled. We should 
 in vain attempt to subdue a pulse by blood-letting, if, 
 at the same time, we should give rich soups to our pa- 
 tients, and yet even a more nutritious substance than 
 this the body is supplied with by its fat. Depletion, when 
 required, may be continued till that quantity appears 
 to be exhausted, for not till then will it be effectual. 
 Whence, if not from the fat, can be derived the full 
 pulse which attends a chronic fever, when blood has 
 been copiously drawn, and the stomach has long re- 
 jected food ? Let not, then, the fear of weakness from 
 venesection or abstinence forbid the use of the lancet. 
 
 Secondly, From the preceding facts and reasonings, 
 can be drawn an answer to the common objections to 
 fasting in the cure of inflammatory fevers, or other 
 diseases requiring depletion. I have already spoken of 
 an advantage to be derived from the use of this reme- 
 dy in dropsy. The evils that are apprehended from 
 this mode of treatment, are all prevented by the slow, 
 yet equable supply of nourishment which the fat sup- 
 plies to the body. 
 
 A third observation, more particularly applicable to 
 the function of the liver, is the case of a diseased sto- 
 mach, when it cannot perform its office in chylopoiesis. 
 That wisdom which made the stomach, foresaw its de- 
 rangement ; and it completed the fabric of the body, by 
 giving fat to supply the place of food, and a liver for 
 its conversion into nourishment. 
 
36 
 
 * 
 
 Lastly, let us subscribe to the doctrine of final causes 
 Aliments, according to their nutrient power, have been 
 divided into grades. Sugar, as containing the most nou- 
 rishment under the least bulk, ranks first in this order. 
 Oil is next to this ; and fat, as uniting other properties 
 for the advantage of the body, was the most suitable 
 substance for its purpose. That obesity which to our 
 eyes may sometimes appear disgusting, is perhaps not 
 a partial evil, but a general benefit. The omentum, 
 which has been considered as useless, or supposed to 
 perform very subordinate functions in the system, ap- 
 pears, from the foregoing facts and reasonings, to be a 
 store of aliment for disease and famine. 
 
 FINIS 
 


 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 

I _ 
 Rush^ .