80 



Scientific Proceedings (126) 



39 (1999) 



The effect of ultra-violet rays on rats, deprived of vitamine A 



in their diet. 



By OLIVE SHEETS and CASIMIR FUNK. 



[From the Biochemical Laboratory, College of Physicians and 

 Surgeons, Columbia University, New York City.] 



Experiments have demonstrated that both xerophthalmia and 

 rickets can be prevented and cured by the administration of cod 

 liver oil, and that rickets can be cured and prevented by sun- 

 light and ultra-violet light. 



We know that the absence of vitamine A from the diet will 

 produce xerophthalmia, and it was believed by some workers, 

 notably Mellanby, that the same deficiency is responsible for 

 rickets. It is generally agreed, however, that the two above 

 named pathological conditions are distinct entities and our ex- 

 periments bear out this opinion. We have investigated whether 

 light has any noticeable effect on growth and xerophthalmia in 

 analogy to its effect on rickets, presumably on account of a bet- 

 ter utilization of the stored vitamine A in the body. 



With this view in mind the following experiment was under- 

 taken : 



Twelve young rats of the same age were placed upon a diet 

 as nearly free as possible from vitamine A. The diet used was 

 that of Osborne and Mendel (with oxidised casein and oxidised 

 lard), and as source of B vitamine, a yeast preparation was 

 added. The rats were divided into two lots of six each. One 

 lot was exposed for five minutes daily to the action of a carbon 

 arc lamp for three weeks, and for the remainder of the experi- 

 ment for three minutes daily, except Sunday, to ultra violet light. 

 The animals were kept in an animal room that received the usual 

 amount of daylight. 



CONTROLS 



Rat. 



No. 



Init. weight 

 February 2 



Fin. weight 

 June 17 



Xerophthalmia 

 after 



25 



$ 



36 grams 



70 



134 days 



26 



6 



28 grams 



69 



129 davs 



29 



$ 



37 grams 



86 



137 days 



32 



9 



43 grams 



92 





33 



9 



'.','■'< grams 



74 





35 



9 



51 grams 



102 





