Histogenesis of the Adipose Tissue. 431 



nor by Weigert's elastic tissue stain. It may be stained by fuchsin, 

 eosin, Congo red, etc, 



Altmann's granules are present in the protoplasm of the fat cell 

 from the time it begins to assume the rounded form. There is no 

 conclusive evidence, however, that they stand in any intimate rela- 

 tion to the formation of fat, since protoplasmic granules which stain 

 similarly are of siich widespread occurrence. Metzner (23) has 

 attempted to show that these granules are directly transformed into 

 fat droplets, but his observations are far from convincing. 



Text Figure 12. F;it lobule tVoiii renal adipose tissue of a 40 cm. foetus. 

 IMie (lai'k luiflei are in some stage of division, f, spaces occupied by fat; 

 III, mitotic figures. Fixation, Zenker's fluid. Stained heavily with iron- 

 haMU. X ^00- 



Growth of adipose tissue. 



It has been pointed out that the blood vessel is the center around 

 which the fat lobule develops. Whether in a mass of preadipose 

 tissue, or in ordinary connective tissue, the first fat cells appear 

 immediately around the blood vessels. The lobules thus established 

 increase in size to a large extent by the addition of cells adjacent 

 to the periphery. The increase in the number of fat cells is, how- 

 ever, to a considerable extent due to the division of fat-free cells 



