EFFECTS ON THE INTEGUMENT 131 



According to Marie ('08 '10), there is found in pellagra a precocious tendency 

 to alopecia, with sclerosis and pigmentation of the ectodermic structures. 



Deficiency in Salts. — Von Hoesslin ('82) gives some weights of the skin in 

 dogs on nearly iron-free diet, but unfortunately normal controls are lacking. 

 Roughening of the hair coat was observed in puppies by Quest ('06) with calcium- 

 poor diet, and by Masslow ('13) with phosphorus-poor diet. Babcock ('05) 

 found in cows on low salt rations during lactation no decrease in the milk yield 

 for a considerable period of time, and a slight increase in fat content of the milk. 

 Meigs ('22) reviewed the effects of partial inanition upon lactation, concluding 

 that a marked deficit of calcium or phosphorus may not affect the amount of 

 secretion for a long time, whereas a serious shortage of protein, fat or carbohy- 

 drate causes an immediate reduction. 



In rickets the skin may be affected in children (Cheadle and Poynton '07). 

 In rats subjected to experimental rickets, by deficiency in phosphorus or calcium 

 and antirachitic vitamin, the skin becomes emaciated, and the hair coat fre- 

 quently appears rough and uneven (McCollum, Simmonds, Shipley and Park 

 '21; Shipley, Park, McCollum and Simmonds '21; McCollum, Simmonds, 

 Kinney, Shipley and Park '22). Jackson and Carleton ('23) found a markedly 

 subnormal weight of the integument in rachitic rats, even when the body weight 

 appeared normal (Table n). 



Smith ('17) and Hart and Steenbock ('18a) found that a deficiency of iodin 

 in the diet of pregnant sows results in the birth of weak, hairless pigs, with 

 edematous skin and undeveloped hoofs. This condition, which is ascribed to 

 malfunction of the enlarged fetal thyroid gland, may also occur in sheep, and 

 occasionally in cattle and horses. 



Vitamin Deficiency. — Funk and Macallum ('14) found the feathers and beak 

 apparently normal in a chick whose growth was suppressed for several months 

 by a diet of unpolished rice and cod liver oil. In chicks and pigeons on polished 

 rice diet with experimental polyneuritis, Tasawa ('15) found the skin atrophic, 

 thin and dry; the fat in the subcutaneous tissue and elsewhere greatly reduced in 

 amount. In the so-called "wet" beriberi of man (due to deficiency of vitamin 

 B) edema and anemia of the skin are characteristic. 



According to Emmett and Allen ('20) and Funk ('22), lack of vitamin A in 

 the diet of young rats produces a coarse and sparse hair coat. Cramer ('20) 

 claims that if rats are deprived of vitamins for 25 days, the lipoids disappear 

 from the "brown fat" (as well as from the suprarenal cortex); hence he proposes 

 to call this type of adipose tissue the "lipoid gland" or "cholesterin gland." 



The experiments of McCollum and Simmonds ('18) indicate that vitamins 

 (A and B) are not synthesized in the mammary gland by the nursing mother 

 rat; therefore if vitamins are absent from the diet they are lacking also in 

 the milk, and the young fail to grow properly. 



Scurvy. — The skin undergoes characteristic changes in scurvy, which is 

 caused by a deficiency in vitamin C. Hoist and Frolich ('07, '12) discovered 

 that scurvy can be produced in young guinea pigs by a diet of oats or other 

 cereals with water. The characteristic cutaneous hemorrhages occur; likewise 

 subcutaneous edema, but only occasionally. Petechiae in the follicles of the 



