50 THE VITAMINS 



dealing with substances kindred to but not identical with the natural 

 product." 



The various claims as to the curative properties of certain quinoline 

 and glyoxaline derivatives to pigeons suffering from polyneuritis led 

 Gulland and Peters (1929) to repeat some of these experiments under 

 very carefully standardized conditions. They give a standard dose of 

 a torulin preparation which is curative for about 3 days, before giving 

 the substance under test. If, after this, the test substance is not effec- 

 tive, but it is subsequently possible to reHeve the symptoms by the use 

 of a second dose of torulin, the negative answer is considered decisive. 

 Neither 4- (nor 5) glyoxalinemethylethyl carbinol hydrochloride, nor 

 2,6-dihydroxyquinoline showed curative properties similar to torulin. 

 The following compounds containing glyoxaline or pyrimidine rings 

 had no curative effects : 2,6-dihydroxyquinoline-4-carboxylic acid ; 4-hy- 

 droxy-2,6-dimethyl pyrimidine; 2-hydroxy-4,6-methyl pyrimidine; 

 2-thiol-4 (or 5)-aminomethyl glyoxaline; ergothioneine hydrochloride; 

 2-methyl glyoxaHne; glyoxaHne-4-(or 5 ) -formaldehyde ; 4-(or 5)-[gly- 

 oxaline-4(or 5)-methyl] glyoxaline-5-(or 4)-methyl alcohol; glyoxa- 

 hne-4-(or 5)-acetic acid; d/-a-hydroxy-/5-glyoxaline-4-(or 5)-propionic 

 acid. 



The question is still open whether Sahashi's temporarily positive 

 results are attributable, as Peters suggests, to "pseudo-cures" or whether 

 the negative results obtained with some substances are to be ascribed 

 to the duality of the nature of vitamin Bi postulated by Guha and 

 Drummond (1929). 



In spite of the uncertainty which still exists concerning the nature 

 of vitamin B after nearly twenty years of intensive research in many 

 laboratories, Drummond (1930) is of the opinion that "there are 

 grounds for some optimism regarding the future of research into the 

 nature of the antineuritic vitamin B. It appears to be a basic substance 

 of relatively simple composition and it should, therefore, be only a 

 matter of carrying out the fractionation on a sufficiently large scale 

 to obtain enough of the active substance, or substances, to establish 

 their nature and constitution." 



Development o£ Knowledge of the Growth-Promoting 

 Function of Vitamin B 



Osborne and Mendel in 1911 and again in 1912 had pointed out 

 the superiority of their experimental rations containing "protein-free 

 milk" over mixtures of purified proteins, fats, carbohydrates and salts, 



