NUTRITION AND GROWTH 585 



better still, an extract of rice polishings, is added to the polished rice 

 diet. The extract is made by means of slightly acid 91 per cent alcohol, 

 and from it Funk has succeeded in separating a substance in crystal- 

 line form apparently related to the pyrimidines, which it will be re- 

 membered are a characteristic constituent of the nucleins. Doses as 

 small as 0.02 to 0.04 gm. of this material given by mouth were adequate 

 to cure the polyneuritis of fowls in from six to twelve hours; indeed, in 

 some cases the bird seemed quite well after three hours. A similar sub- 

 stance has also been extracted from yeast, milk, brain and lime juice, 

 and it has been called, for want of a better name, vitamine. 15 



It is quite likely that other diseases, such as scurvy, may also be due 

 to the absence of some vitamine in the diet some substance, namely, 

 which in the case of this particular disease would seem to be absent in 

 preserved food, the continued taking of which is so frequently its cause. 

 Fresh fruit and other foods added even in small amounts to such a diet 

 would appear to supply the necessary vitamine. 



It is not the higher animals alone that suffer from the want of some 

 such substance as vitamine. It has been shown, for example, that, when 

 a normal artificial culture medium is inoculated with yeast in very 

 small amounts, it fails to grow, whereas the same quantity will grow 

 luxuriantly in a medium to which sterilized beer wort has been added. 

 Vitamine is not of the nature of a ferment, since it withstands heating 

 to 120 C. for more than an hour. The addition of yeast to dietaries 

 that are deficient in vitamines is an excellent corrective. 



Returning now to the accessory substances that seem to be adherent 

 to certain forms of fat, we see at once that they can not be exactly 

 the same as the so-called vitamine of Funk, for they contain no nitrogen. 

 There are, therefore, probably two accessory factors concerned in ade- 

 quate growth. One of these must be present in the protein-free milk 

 which serves as a constituent of the basal diet used in Osborne and 

 Mendel's experiments, for we have seen that animals will grow on this 

 for a certain period, provided the proper amino acids are present. 

 Later, however, they pass into a state where there is no growth but 

 adequate maintenance. If now the other accessory factor is added, as, 

 for example, butter fat or a small amount of milk itself (i. e., in place 

 of protein-free milk), then growth will be resumed at its normal rate. 

 "Either of the determinants may become curative. Both are essential 

 for growth when the body store of them becomes depleted." McCollum 

 suggests that these accessory factors should at present be called the 

 "fat-soluble A" and "water-soluble B." The latter is present in yeast 

 cells, in fat-free milk, and in many other animal foods, and is probably 

 the same as Funk's vitamine. The former is soluble in the fat solvents, 



