VIII. EFFECTS OF DEFICIENCY 



293 



period of 3 to 4 months. Necrosis of the tail often develops in late stages 

 of the deficiency, and hematuria is sometimes observed. These outward 

 manifestations of derangement are not exhibited regularly, liut histological 

 changes are in\'aria])ly found in kidneys of fat-deficient rats. 



Subsequent studies by Burr and his coworkers indicated that the water 

 consumption^ and basal metabolic rate* of the fat-deficient rat are higher 

 than those of the normal animal. The ability of animals to reproduce is 

 impaired by fat deprivation.'* In the female rat, conception is followed by 

 resorption of all or some of the fetuses,*' ^'^ the gestation period is pro- 



FiG. 7. Schachtelhalmschwanz — exaggerated caudal symptoms of fat deficiency 

 in the young rat. (From Guggenheim and Jiirgens.^) 



longed, and only a variable and low number of live young are produced. 

 These, however, do not live long after birth, and even at^the age of a few 

 days show damage of the tail (Fig. 7). The male rat on a fat-free diet 

 becomes sterile and will not mate.*' ^ The ability to reproduce returns when 

 the animals are given diets containing adequate essential fatty acid. 



When weanling rats are placed upon a fat-free diet, fat-deficiency symp- 

 toms begin to appear within 3 months, and the animals can be maintained 

 in the fat-deficient condition well over a year with moderate mortality. 



" G. 0. Burr and M. M. Burr, /. Biol. Chem. 86, 587 (1930). 



^G. O. Burr and A. J. Beber, Proc. Soc. Expil. Biol. Med. 31, 911 (1934). 



«E. C. Maeder, Anat. Record 70, 73 (1937). 



7 H. M. Evans, S. Lepkovsky, and E. A. Murphy, J. Biol. Chem. 106, 431 (1934). 



8H. M. Evans, S. Lepkovsky, and E. A. Murphy, /. Biol. Chem. 106, 445 (1934). 



