472 



THE METABOLIC PKOCESSES OF THE BODY. 



time increasing in bulk while remaining round or becoming more distinctly 

 so, and the smaller drops run together into larger ones [Fig. 118]. This 

 goes on ; the fat increasing in quantity coalesces more and more, and the 

 cell, as a whole, becomes larger and larger, the cell substance at first keep- 

 ing up in bulk with the increasing fat, but subsequently ceasing to increase, 

 being apparently used up in the formation of the fat. Thus the original 

 small " protoplasmic " cell is at last transformed into the larger fat-cell, all 

 the fat having run together into a vesicle the envelope of which, thickened 

 on one side to carry the nucleus, is furnished by the remnant of the cell 

 substance. In some cases, the nucleus instead of being pushed early on one 

 side, remains central though the collection of fat has become considerable ; 

 it is, however, eventually displaced. The whole process appears very similar 

 to the deposition of mucin in the cells of a mucous gland ( 205) ; and we 



J 



Deposition of Fat in Connective-tissue Cells : /, a cell with a few isolated fat-droplets in its 

 protoplasm ; /, a cell with a single large and several minute drops ; /', fusion of two large drops ; 

 g, granular or plasma cell, not yet exhibiting any fat deposition ; c. t., flat connective-tissue cor- 

 puscles ; c. c., network of capillaries.] 



may by analogy infer that the fat-cell becomes a fat-cell by the cell manu- 

 facturing fat in some way or other, and depositing the fat so formed in 

 the interstices of its substance. The most striking superficial distinctions 

 .seem to be that in the mucous cell the granules or spherules remain discrete 

 within the cell, being separated by bars of cell substance, whereas in the fat- 

 cell the globules, as they form, run together until at last they unite into a 

 single mass; and further that while in the mucous cell, even when most 

 heavily loaded, a relatively large amount of active cell-substance still re- 

 mains, in the fat-cell a mere remnant is left and that chiefly surrounding the 

 displaced nucleus. 



Some observers are of opinion that the cells belonging to connective tissue 

 which thus become fat-cells of adipose tissue belong exclusively to the kind 

 which we spoke of as plasma cells, but this is doubtful. Others again, while 

 admitting that the cells which become fat-cells resemble in appearance or- 

 dinary connective-tissue corpuscles and may like them be branched, believe 

 them nevertheless to constitute a special kind of connective-tissue corpuscle, 

 being led to this view by the fact, that though adipose tissue is very generally 

 distributed throughout the connective tissue of the body, it is apt to appear 

 in particular situations, rather than in others, and in some tracts of connec- 

 tive tissue never under normal circumstances makes its appearance. Others 

 again maintain that, under favorable circumstances, any connective tissue 

 corpuscle may become a fat-cell. 



