412 .E. T. Bell. 



that the fat dejwsits in epithelium, cartilage, and muscle take any 

 part in the normal metabolism of the cell. 



An ajDparent exception to the conclusions stated above is found in 

 Hansemann's observation that in swine the renal epithelium contains 

 almost no fat when the animal is j)oor, but a large amount when the 

 animal is very fat. Hansemann regarded the fattened condition in 

 swine as abnormal and analagous to obesity in man. More extended 

 observations will be necessary to settle this point. 



SUMMARY OF PART I. 



Fat droplets were found in the cells of the liver in nearly all the 

 fcetuses examined — the youngest being 4.7 cm. long. Fat was also 

 found in the hepatic cells of two moderately fat steers. 



Fat droplets were found inside the muscle fibers from the 7 cm. 

 to the 28 cm. stage. No fat was found in this situation in older 

 foetuses, but in three very thin steers, about one year old, fat droplets 

 were found inside some of the muscle fibers of several muscles. This 

 is, however, due to atrophy. 



The cells of hyaline cartilage were found to contain fat droplets 

 throughout foetal life (from the 7 cm. stage) and also in the adult. 



The renal cells of some fcetuses contain fat droplets. In certain 

 parts of the kidneys of two large fat steers, the cells of the renal 

 tubules were loaded with fat droplets. 



The fat droplets found inside epithelium, cartilage, and muscle, 

 unlike the fat in the fat cells, is independent of the nutritive con- 

 dition of the animal. 



II. On the Histogenesis of the Adipose Tissue of the Ox. 



The development of adipose tissue has been the subject of numer- 

 ous investigations. The work of Flemming stands out preeminently. 

 The last comprehensive paper was published by Hammar in 1895. 

 Since the appearance of Hammar's paper, our histological technique 

 has been greatly improved by the introduction of Mallory's con- 

 nective tissue stains, Scarlet red, and Sudan, It is hoped that a 

 careful study of one species with the advantages of the newer methods 

 has brought out enough new facts to justify a revival of the question. 



