OF THE COMMON ADIPOSE TISSUE. 135 



seen it; butM. Chevreul has recently discovered in the blood, 

 a fatty matter, held in solution by the other materials of that 

 fluid. Butter is another fatty, coloured and odorous substance, 

 held in solution in the milk. There is also in the nervous 

 substance, a fatty, crystallizable matter, analogous to that of 

 the blood. Finally, in cases of disease and cadaveric changes, 

 other fatty matters are found in the human body. 



164. The adipose tissue, in animals, presents some differ- 

 ences; it exists in the greater numbers; it is found in the ar- 

 ticulata, the mollusca, and the vertebrata. In the latter, the 

 fat presents various degrees of consistence, colour, &c.; it is 

 very fluid in fishes and the cetacea; the head of the physeter 

 macrocephalus, contains a liquid oil, in which is found a con- 

 crete fatty matter, called spermaceti or cetine. In the hog it 

 is soft, forming lard, firm in the ruminantia, where it is called 

 tallow, &c. The volume of the adipose vesicles is not the 

 same in all animals: according to Wolff, they increase succes- 

 sively, in the hen, the goose, man, the ox and the hog. Fat 

 accumulates also, in different regions, in different animals, as 

 on the back of the camel, the tails of some sheep, &c. The 

 Bushman tribe is remarkable for the fatty protuberance of 

 the rump in the women : an example of which has been recently 

 seen in the Hottentot Venus, exhibited in Europe. 



165. The different degrees of plumpness establish great 

 differences in the quantity of fat. In a complete state of obesi- 

 ty, it forms from the half to four-fifths of the total weight of 

 the body. In extreme leanness, on the contrary it exists only 

 in some places. Women have, commonly, more of it than 

 men. It varies remarkably, according to age. The foetus has 

 none at all, until the period of gestation is half over. From 

 this epoch to the birth, fat successively accumulates in the dif- 

 ferent parts. It is found at first under the skin only, and is 

 there produced in isolated grains, which render its study at 

 this age peculiarly easy. At birth, a large quantity is already 

 found under the integuments, and in the thickness of the 

 cheeks ; the epiploon also, has some isolated grains of it. The 

 quantity of fat,augments with the increasing growth, and ends by 



occupying the interstices of the muscles, but a long time elapses 

 19 



