326" INTEGUMENTS. 



fied, and then appears in small aggregated masses of cfiffererrf 

 shapes and sizes. 



In chemical composition it differs from all other parts of the 

 body by the absence of nitrogen, and is formed of oxygen, hy- 

 drogen, and carbon, which render it, in animals, a very suita- 

 ble- article for candles and lamps. According to the analysis 

 of Chevreuil,* it consists of two kinds of matter, elain and stea- 

 rin; the former of which remains fluid at the freezing point, 

 while, as mentioned, the other becomes solid by a very small 

 abatement of its living temperature. The application of porous 

 paper enables one to separate them in a small way. 



The adeps, though lodged in the cellular substance, is accom- 

 modated there under different circumstances from the cellular 

 serosity, and is supposed to be in different cells. This doctrine 

 was promulgated by Dr. Wm. Hunter,^ and upon the following 

 grounds: That certain parts of the cellular membrane are des- 

 titute of it; that in persons who have died from dropsy, the 

 portions of the cellular membrane which originally contained 

 fat, have a more ligamentous condition than others ; to wit, those 

 on the loins next to the skin, more than the stratum next to the 

 lumbar fascia; that water or flui'ds pass readily from a higher 

 to a lower part of the cellular membrane, either when extrava- 

 sated naturally or injected; that oil, when injected artificially,. 

 subsides*in the same way, and has a doughy or oedematous feel, 

 yielding readily to pressure and pitting, whereas, fat never 

 shifts its position simply from gravitation. 



From these several causes, Dr. Hunter adopted the opinion 

 that the fat of the cellular membrane is lodged in peculiar ve- 

 sicles, and not as the water of anasarca, in the reticular inter- 

 stices of parts. This idea has been adopted by Beclard, who 

 says that the lobules of fat, when examined with a microscope, 

 are seen to be composed of small grains or vesicles, from the 

 six hundredth to the eighth huridreth part of an inch in diame- 

 ter, each one having a pedicle furnished from the adjacent 

 blood vessel. That the parietes of the vesicles are so fine as to 

 escape observation, but that he considers them as arranged in 

 the same way with the pulp of oranges, lemons, and such kind 

 of fruit. These several reasons a?e so plausible that I cannot 



* Annalcs de Cliimie, vol. xciv. 



t Medical Observations and Inquiries. London, 1762, 



