406 E. T. Bell. 



24.7 cm. foetus. In the renal epithelium of the columns of Ber- 

 tini fat droplets are present, elsewhere in the kidney they are absent. 

 The renal preadipose tissue contains no groups of fat cells at this 

 stage — it is all in the branched^cell condition (Fig. 6, Plate II). In 

 certain lobules nearly every cell contains fine fat droplets (Fig. 7, 

 Plate II). The fat is more abundant near the nucleus, but occurs 

 far out in the processes of the cells. These cells have no special 

 relation to the blood vessels such as is found when groups of true 

 (rounded) fat cells are forming. Such spindle-shaped cells, contain- 

 ing fat droplets, are common on the edge of a growing fat lobule ; 

 but it seems striking to find all the cells of the lobule containing 

 fat before any true fat cells are formed. The cells of the cartilage 

 of the vertebrae contain fat. The erector spinse muscle contains con- 

 siderable fat in the fibers next to the lamiufe of the vertebrae, but 

 very little is found elsewhere. Xo fat is found in the fibers of the 

 psoas muscles. 



After about the 22 cm. stage, true fat cells begin to appear first 

 in the preadipose tissue of the brisket'^ and renal region and later 

 in other situations. Only scattered observations have been made 

 as to the fat content of the tissues after this period. 



28 cm. foetus. The liver contains a considerable amount of fat. 

 Exceedingly fine fat droplets are found in the muscle fibers. 



37 cm. foetus. The liver, kidney, and psoas muscles were examined. 

 No fat was found. 



40 cm. foetus. A large amount of fat was found in the liver. 

 No fat was found in the kidney. The fibers of the psoas muscles 

 contain no fat, but a clump of fat cells was found near a blood 

 vessel in the intermuscular connective tissue. 



43 cm. foetus. The hepatic cells contain a considerable amount 

 of fat, mostly in the form of fine droplets. Coarse irregular droplets 

 are scattered through the cells of the renal tubules. 



45 cm. foetus. The liver shows a fat content similar to the 43 

 cm. specimen. There is a large amount of fat in both the cortical 



'The iiart of the hrisket between the sternum and the pectoral muscles 

 in the median plane develops into a large mass of fat. It is this part of 

 the brisket that is referred to when that term is used. 



