ANIMAL NUTRITION DISCUSSION AT DUNDEE 425 



Its curative effect was amply demonstrated by experiments 

 on pigeons, a dose of 2-4 cgm. being necessary. 



The aqueous solution is neutral and not acted upon by 

 acids. On boiling with copper oxide no copper salt is formed 

 and therefore it is not an amino-acid. When recrystallised from 

 dilute alcohol the substance melts at 233 , which is the same as 

 that at which the curative substance from rice melts. As the 

 substances behave alike they must be considered to be identical. 

 It is precipitated in a pure state by mercuric acetate as well as 

 by silver nitrate but not by mercuric sulphate nor by the nitrate. 



All these properties suggest that the curative substance is a 

 pyrimidine base analogous to uracil and thymine and that it is 

 probably a constituent of nucleic acid. On this view the two 

 nitrogens would be combined as in other pyrimidine bases in 

 the form of an ureide : 



NH CO 



NH\ 



CO C—CH, Thymine c0 />Ci 6 H l8 6 Vitamine 

 NH CH NH / 



Only a constitution of this kind would explain the neutral 

 character of the substance and its analogy with other pyrimidine 

 bases. 



The curative substance was also isolated by analogous 

 methods from milk (this fact being very important in connexion 

 with infantile scurvy) and bran. Everything suggests that in 

 all these cases the curative substance is identically the same. 

 Further, a substance curing avian polyneuritis was found in 

 lime-juice, which is at present being more closely investigated. 

 These experiments throw an entirely new light on the physio- 

 logical importance of the nucleic substances. 



MORE DIFFICULTIES FROM THE PRACTICAL SIDE 



(Dr. David Wilson) 



The values obtained by the methods in vogue are not a 

 sufficient indication of the relative feeding quality of home- 

 grown foods — grass, roots and fodders— which form the greater 

 part of farm rations. For example, analyses made of samples 

 of grass from five pastures gave the following indecisive results 1 : 



1 Trans. Highla,7id and Agric. Society, 1894, pp. 411-16. 



