Histogenesis of the Adipose Tissue. 429 



in diameter) show a well developed peripheral zone of protoplasm 

 containing Altmann granules. It will be noted that many colla- 

 genous fibers (cf. stained blue) occur crowded between the fat cells. 

 These fibers become included in the adipose tissue during its forma- 

 tion. The preadipose tissue often contains a number of coarse 

 collagenous fibers (note lower right-hand corner of figure) and these 

 are crowded together in thin layers as the fat cells increase in size. 

 These fibers do not occur in renal adipose tissue. The fibers of 

 the renal preadipose seem to be completely absorbed. 



Text Figure 10. ("ell Irom the renal adipose tissue of a 10.5 cm. foetus 

 (about full term), f, spaces occupied by fat; ff, Altmann granules; in, cell 

 membrane; /(. nucleus. Fixation, Zenlvcr's fluid. Stained with ii-on-hipm. 

 X 120(). 



Text Fig. 10 rei)resents a fat cell from the renal adipose tissue 

 of a foetus about at full term (105 cm.). Kearly all the cells of the 

 tissue at this stage are similar to this cell. The border of the cell 

 is wavy because of shrinkage from fixation and embedding. The 

 cell membrane is readily seen. In some parts of the circumference, 

 particularly around the nucleus, a thick zone of granular protoplasm 

 is present. The zone of protoplasm contains Altmann granules 

 and often small fat droplets. 



Text Fig. 11 is from the scrotal adipose tissue of a steer about 31/2 

 years old. The animal was fairly well fattened and weighed 1,260 

 pounds. The drawing shows only a part of the wall of a fairly large 



