CONNECTIVE TISSUE 



63 



FIG. 74. A GROUP OF FAT 

 CELLS FROM THE SUBCU- 

 TANEOUS TISSUE OF A 

 YOUNG RABBIT. 



Cells a show stages in de- 

 velopment; cell b is cut tan- 

 gentially through the nucle- 

 ated pole. X 



fat globules black; sudan ITT, which gives a 

 red reaction : and scharlack K (fettponceau), 

 which also stains fat red. For the successful 

 application of these stains it is required that 

 the tissue has not been previously subjected 

 t<> treatment involving the use of alcohol or 

 ether, since these reagents extract fat from 

 the cells. Fat, in cooling, solidifies and pre- 

 cipitates delicate threads, the margarin crys- 

 tals. 



During periods of starvation or malnu- 

 trition, at which time fat decreases greatly 

 in volume, many of the fat cells return to a 

 condition which approximates their former 

 state. As the fat is removed the cytoplasm 

 of the cell increases in amount, but assumes 

 a peculiar fluid appearance and is not read- 

 ily colored by the usual dyes. These cells, 

 which still contain a number of fat droplets, 

 are known as 'serous' fat cells. 



The origin of the fat cell is still somewhat in doubt. It was for- 

 merly thought that it might 

 result from a deposit of fat 

 within any of the connective 

 tissue cells. A second theory 

 maintains that it arises only 

 from a special fat-forming 

 connective tissue cell. The 

 demonstration of large num- 

 bers of peculiar ovoid granular 

 cells within areas where fat 

 cells were undoubtedly form- 

 ing in fetal and young sub- 

 jects, and the demonstration 

 of similar cells in areas show- 

 ing fat formation in adult tis- 

 sues, has lent support to the 

 hypothesis that these granular 

 cells are the only progenitors of the fat cells (Shaw, Jour. Anat. and 

 Physiol., 1901). According to Weiskotten and Steensland (Anat. Eec., 



FIG. 75. FAT CELLS FROM A TEASED PREP- 

 ARATION OF ADIPOSE TISSUE OF MAN. 

 X HO. 



