THE VITAMINES IN THE ANIMAL KINGDOM 117 



was evidenced by a general undernutrition, a rough coat and a 

 characteristic eye disease, now called ophthalmia (keratomalacia). 

 Since this disease does not occur only in rats, we shall have 

 occasion to speak of it again. It was difficult to bring these new 

 findings into accord with the then prevailing knowledge of vitamines, 

 the more so since Osborne and Mendel (I.e. 72) obtained good growth 

 with fat-free mixtures. Later on, Stepp (327) showed that his 

 "life-sustaining" substances did not belong to the lipoids, and Lander 

 (328) demonstrated that lecithin and cholesterol played no particular 

 part in nutrition. Hence we could not understand why the role of 

 vitamine B was relegated to the background, and even denied. 

 Subsequently, Aron (329) also reported on the importance of butter. 12 

 Although we had already at that time assumed the existence of a 

 special vitamine, associated with fats (in cod liver oil, we assumed 

 the existence of a specific antirachitic vitamine because of the partial 

 lack of vitamine B and the therapeutic influence on rickets) we were 

 somewhat skeptical of the existence of a vitamine in butter. In this 

 we were strengthened by our experiments together with Macallum, 

 particularly since butter was shown to be free from B-vitamine and 

 since it was possible (330), by substituting fresh yeast for dry yeast, 

 adding orange juice, and treating the eyes with zinc sulfate and boric 

 acid solution, to maintain animals in good condition for 150 days. 

 The substitution of butter for lard was without influence in our 

 experiments. All these results are now easily explainable, and yet 

 we must assert that we have observed instances of ophthalmia on a 

 diet containing butter. 13 Our findings showed that the substance 

 present in butter was not the only growth factor, asMcCollum would 

 have it, but that vitamine B is at least quite as important as vita- 

 mine A. This is well illustrated in the curve taken from the work of 

 Funk and Macallum. 



12 Aron (I.e. 319) introduced the method of giving the vitamines as a medicine, 

 so to speak, independent of the diet. This procedure has the advantage 

 that the vitamine addition has nothing to do with the food consumption, 

 although it is not always easy to give the necessary dose to the animals, as 

 we ourselves can verify. 



13 Lately, in association with Dubin (331), we have noted, among 30 rats, 

 2 that developed ophthalmia on a diet containing the usual amount of 

 vitamine A. One of them was improved by the addition of yeast to the diet. 

 The other improved without medication. 



