ADIPOSE TISSUE 



ADIPOSi: 



be two vesicle*, separated by wptum. against which they ware 



jrtilly flattened by pressure (g), or merely separated by a con*- 



in the external wall*, a* in /. This form lead* u to conclude that 



1 : 



fat-cells increase by division. The fat-veaicle of the human subject 

 contain* Margarin, a solid fat, and Olein, a fluid fat These sometimes 

 separate spontaneously, presenting a very beautiful microscopic 

 appearance. The margarin collects in a spot on the inner surface 

 of the cell-membrane, and presents the appearance of a small star, 

 whilst the olein occupies the remainder of the vesicle, unless when this 

 quantity of fat in it is rather smaller than usual, in which case we 

 may observe a little aqueous fluid between the olein and the 

 cell-membrane. (Pig. 1, A.) 



The chemistry of the substances Margarin and Olein is somewhat 

 complicated, but the function of the adipose tissue cannot be explained 

 without it These two substances, with Stearin, are the most widely 

 distributed fata in the organic kingdom, but they are not the only 

 ones. They were formerly regarded as salts formed by fatty acids with 

 Glycerin. Recent investigations have however shown that this view 

 requires a slight modification. Rerzeliu.- thinks tliat glvcerin does not 

 exist ready formed in the neutral fats, but that it is a product of the 

 formation of soap ; and he considers the base of the neutral fata to be 

 the oxide of a radical (C, H,) which he terms Lipyle. Glycerin is then 

 formed from two equivalents of the oxide of lipyle, with three equi- 

 valents of water: 2 C. H, O + 8 HO=C.H, (T If to this we add 

 one equivalent of water, we obtain the usual formula. 



According to this view, which is supported by Redtenbacher, 

 Varrentrap, and Mulder, the base of every neutral fat yielding glycerin 

 is a compound which is represented by C, H, 0. 

 The moat important of the fatty acids are : 



Stearic Acid C M H M 0. + H 



Margaric Acid .... (\. H ,. O, + 11 o 

 Oleic Acid C (l H.,,0. + II n 



These are universally diffused in plants and animals ; and, combined 

 with the oxide of lipyl.- |C, H, < M, they form the neutral fats stearin, 

 margarin, ami ..lein ; and thin is the funn in whii-h they most commonly 

 occur in the organic kingdom. Sometimes, however, a more powerful 

 bam (potash, soda, &c.) removes the oxide of lipyle, and there are 

 then formed compounds of the fatty acids \\ ith alkalies. 



In connection with this subject, Mulder observes that " when salad- 

 oil is conveyed into the stomach, it may pass unchanged into human 

 fat, for both consist of margarin and oleiu, although in different propor- 

 tion* ; and as margarin and olein are found in many vegetables used 

 for food, nothing is more simple than to assume that these substances 

 are directly transferred, without change, into the fats of the animal 

 body. 



" But if these same vegetables are eaten by a sheep, the olein and 

 margarin must undergo some change in the body of the animal, since 

 mutton-fat contain* a large amount of stearin. In this case the change 

 e^y understood, for 2 eq.niargaricar; I ' H _ o,,) = 1 eq. stearic 

 acid (C H,, O 4 ) + 1 eq. oxygen. Thus, from two equivalents of 



margaric acid one equivalent of stearic aciil is prodm-cd, and 



equivalent of oxygen i" giv.-n oft". In all probability suchadeoxidation 

 of the margaric acid in the f.,,,.1 of the sheep is really cflected : ami 

 on the contrary, when mutton-fat is used for food by man, stearic acid 

 is most probably converted into margaric acid by the absorption of 

 oxygen.' It is now believed by our first physiologists, that the neutral 

 faU taken as food do not directly form fatty tissue. 1>ut. that they enter 

 the blood in a xajH.nilied state. In fact the alkaline character of the 

 bile as it enters the duodenum renders it impossible for the fat to 

 enter the blood without undergoing this change. If it be *ap. 

 we readily understand how compounds of fatty acids and soda 

 exnt in the lilood and in various parts of the body. When a soda- 

 soap however exists in the blood, it eammt form a neutral fa- 

 as margarin or olein. without combining with glycerin. Th. 

 to the inquiry, in the first place, whether these soap 

 glycerin ; and secondly if they do, whether the glycerin would combine 

 with the fatty acids and form neutral fate. There w good reawm for 

 believing that both these question* may be answered in the negative, 



for the glycerin set free when the *oda-*onp i' formed, is m,. : probably 

 at once decomposed ; and further, glycerin will not remove the soda 

 from the fatty acid ami form a n. 



It has been suggested by Mulder, that although glycerin will not 



enter into this con , lipylc in a nascent state may 



do so, and that in this manner the fatty acids may be converted int.. 



!at. and deposited in the cellular tissue, and other part.- 



have already shown that (accord opinion of 



: the r.idi. !'>'< The 



second oxide of this radical e . a. id. which is snp|.-. 



the great majority nt in most partu of tnebodv. 



When .in u white subii- 



mate, the composition of which is r II o ; while the compoait 

 the oxide of lipyle is C, H, 0. 



It may happen that there are cause* of n at work 



by which some of the substance* , \ert.-d int 



acid are mode to produce oxide of lipyle, which in the nascent state 

 unite* with tin- fat' 1 fats. 



Hence in all probability the neutral fats are not deposit 

 and unchanged in the cellular tissue, but are first saponified 

 entering the blood as margarate and oleate of soda, are again r< 

 to neutral fats by the influence of lactic acid. 



The next question for our consideration is the formation of fat a 

 subject which has given rise to much angry an. I 



between the leading chemists of France and Germany. I o:m.-is. who 

 may be regarded as the representative of the Kivnch school, maintain* 

 that all the fat of animals originates in and is obtained from plant* ; 

 while Liebig, on the contrary, maintains that a portion ,.f it is formed 

 by the animal itself, from starch, sugar, and gum. The goose was the 

 animal respecting which the dispute originated. When fatten. -.I with 

 Indian corn, the starch must, according to Liebig, hare been changed 

 into fat, because he had found but a minute quantity (about 1 part 

 in 1000) of fat in that kind of grain. Dumas however extracted '.< |NT 

 cent of fat from Indian corn (or ninety times as much as Liebig 

 thus he found in the food which the goose had eaten much more fat 

 than had to be accounted for. The actual fact is, that the amount of 

 fat in this grain is so variable that no conclusion can be drawn from 

 the experiment Liebig quotes many examples of substances whi'h, 

 although they contain little fat, are well known by experience to be 

 especially tit for fattening the animal body. Rice, peas, beans, and 

 potatoes are all known to possess this property; yet lice L -.\. 

 0'2 to 0'8 per cent, of matters soluble in ether ithe ordinary means of 

 determining the amount of fat); peas I-L'II to J-l ; beans 07", and 

 dried potatoes 0'35 per cent. Thus any animal that has eaten limn 

 pounds of one of these substances may obtain from them 2 to 8, 12 to 

 21, 7, or 34 pound* of fat respectively. He makes the following 

 calculations: Three pigs to be fattened in thirteen weeks require 

 1000 pounds of peas, and 6825 pounds of boiled potatoes, the latter 

 being equal to 1638 pounds of dry potatoes. These contain in all _'<; 

 pounds of fat, the peas yielding '21 pounds, and the potatoes 5. One 

 fattened pig gives on an average 50 to ."..' pounds of fat. the three 

 yielding 150 to 165 pounds. Each pig be- 



average 18 pound* of fat that is, 54 pounds for the tin. . It to these 

 .VI pounds be added 26 pounds contained in the food, we get 80 pounds; 

 and if we subtract these from 150 to 165 pounds, there is a remainder 

 of 70 to 85 pounds of fat produced from the starch, &c., of the food. 

 Liebig's opinion is further strengthened by the circumstance that snrne 

 fats are undoubtedly produced in the body, as, for instance, t! 

 peculiar to the brain, C'/i/<. -. I'kocenine, 4c. To obtain 



these from other fat requires just as much a new arrangement as if 

 they were produced from starch ; hence, in a scientific point of 

 there is nothing improbable in the supposition that animals are able 

 to produce fata. 



With regard to the formation of fat in plants, it is worthy of obser- 

 vation that all seeds which yield oil on pressure a* the castor-oil seed, 

 hemp-need, &c. contain starch in their early stages, this 

 disappearing as the oil increases, and when the seed in e..nn 



<d not a trai f the starch remaining. This rend. 



probable that these fatty matters are formed from starch, i-'rom their 

 ultimate c..ni]Kisition it is obvious that whenever fats are prod tic -d 

 from any sub-t;mce there must lie produced at the same time either 

 highly oxidised compounds, or else that oxygen must In' itself hit-rated. 

 Liebig observe* that if from the formula forst.i.l. i 11 n M)) we 

 take nine equivalent* of oxygen, there will remain in 100 parts 



C,, T'.' I 



II 10-8 



O 9.8 



The empirical formula for fat which come* nearest to this is C,, H 10 

 O, which gives in 100 part* 



C,, 78-9 



11-6 



O 9-5 



thi- fornml'i an equivalent of starch, in order to be 

 on\ei-ted into fat, would lose one equivalent of carbonic acid and 

 seven of oxygen, or (expressed in symbol*) C,, H 10 O 10 = C,, H 10 O 

 + CO,* 7 O. 



