FACTORS FOR ANIMALS 



was precipitated by 70 % alcohol and then solubilised by the action of 

 enzymes.^ It was said to be different from folic acid. 



Guinea-pigs required two other factors not essential for rats or 

 chicks. These were present in yeast and winter milk respectively/ 

 and also in linseed oil meal.^» ^ What may or may not have been the 

 same three factors were termed by D. W. Woolley and H, Sprince/ 

 factors GPFi, GPF2 and GPF3. The first of these was probably 

 identical with folic acid and the second with a mixture of cellulose and 

 casein. K. A. Kuiken ^ also claimed that guinea-pigs required 

 unknown factors in rice polish, brewers' yeast, dried grass or liver, 

 and that commercial casein contained a further factor absent from 

 vitamin-free casein. 



Cartilage Factors 



Hegsted et al.^ claimed that a factor present in cartilage, kidney 

 and rice was necessary for chicks, which in the absence of this factor 

 developed a dermatitis similar to that observed in pantothenic acid 

 deficiency. Robinson et al.^ reported that chondroitin sulphuric 

 acid could serve as a growth factor for both the rat and the chick, and 

 that its effect was different from that of the anti-dermatitis factor found 

 in a filtrate from rice polishings, that is, presumably, pantothenic acid. 



According to a later paper by Hegsted et al.}^ the cartilage factor 

 is a combination of chondroitin, glycine and arginine ; each alone 

 failed to stimulate the growth of chicks, and even when combined the 

 weight restoration was not equal to that obtained with cartilage. 

 Chondroitin alone, however, gave a marked response when the amount 

 of casein in the diet was increased. Subsequently it was shown ^^ 

 that cystine must also be present if growth equivalent to that produced 

 by cartilage was to be obtained. 



A combination of these four factors prevented gizzard erosion, 

 which had been attributed to the absence of a specific factor by H. J. 

 Almquist and his colleagues,^^ and by C. A. Elvehjem and his 

 colleagues.^^ H. R. Bird and J. J. Oleson ^^ believed that the anti- 

 gizzard erosion factor was present in a chondroitin fraction from carti- 

 lage, whilst H. J. Almquist ^^ believed that it was cholic acid. It has 

 now been shown that vitamin B^g prevents gizzard erosion in chicks. i^° 



Zoopherin 



A factor similar to the chick factor from cow manure (page 544) 

 was termed " nutritional factor X " by Gary et al}^ Both factors 

 may be identical with the factor termed by Zucker et al.^'^ zoopherin. 

 Zoopherin deficiency revealed itself in rats after the natural lactation 

 period by a marked growth restraint, high mortality, high blood urea 



619 



