FAT. 225 



the contents of the fat vesicle fluid and transparent, without, 

 at the same time, diminishing its size, as is proved by the 

 fact that on the re-solidification of its contents, the vesicle 

 presents the same form and dimensions as at first. 



Again, acetic acid, according to Henle, acts upon the fat 

 vesicle as upon the milk globule, destroying the membrane 

 in different places : it permits the escape of a number of 

 globules of oil or grease, which, like pearl-drops, remain at- 

 tached to the larger vesicle. 



Ether, however, produces other effects than those usually 

 described, and which are mentioned above ; thus, when ap- 

 plied to the fat vesicles of the pig, many of them will be seen 

 to burst, and to collapse frequently to less than the fourth 

 of their original size, losing, at the same time, all definite 

 form, and, in proportion as the vesicle collapses, one large 

 circular drop, or two or three smaller ones, will be seen gra- 

 dually to form around and envelope the shrunken vesicle, 

 which is, however, never entirely dissolved. 



There are other observers again, as Schwann and Henle, 

 who consider that fat vesicles are not merely provided with an 

 envelope, but that they are true cells possessing both cell 

 wall and nucleus. 



Thus Schwann noticed in the wall of the fat vesicles of 

 the child already referred to a nucleus of round or oval form, 

 sometimes flattened, and sometimes not so. 



Furthermore Henle writes, " very frequently the wall 

 presents a salient point on some part of its extent, and in 

 that position exists a nucleus, or a trace of a nucleus. Some- 

 times there are two nuclei, and in very many cases they can- 

 not be observed at all."* 



Again, Mandl has made the observation in examining the 

 fat tissue of young rabbits, and especially in taking the little 

 masses of fat which lie along the vertebral column in the 

 interior of the pectoral cavity, that the vesicles appear but 

 half filled, and that they consist of two parts, an inner one 

 conveying the aspect of a drop of oil, and an outer mem- 

 branous portion, f 



* Anat. Gen. p. 422. -j- Anatomie Microscopique, p. 141. 



T 2 



