Temperatures at or above 100° C. upon Vitamines. 65 



one-tenth. The results in this series reveal all the imperfections alluded to 

 elsewhere (see preceding paper) by the authors as peculiar to the curative type 

 of experiment. 



The material used in these experiments had rather a low water content, 

 10 per cent., and the vitamine present might be supposed to be protected 

 from destruction on that score. A similar set of data are now being obtained, 

 using a soluble yeast extract, containing over 60 per cent, water, whose 

 vitamine content, reckoned on dry weight, is of about the same order as that 

 of wheat germ. These experiments are not yet complete, but enough results 

 have been already obtained to show that the extra water present during the 

 heating has not enhanced at all the destructive effect of high temperatures 

 upon the active substance. 



It is therefore justifiable to apply the results obtained above with pure 

 wheat germ to such processes as the baking of bread, biscuit, etc., where the 

 . water content may approach 50 per cent. The time taken to bake an 

 average loaf does not exceed one hour, and the internal temperature rises to 

 about 101'° C. We may therefore conclude that, if wheat germ is included 

 in the flour from which the bread is made, its anti-neuritic (anti-beri-beri) 

 properties will survive the baking process, suffering very little damage. 



The rapid destruction of anti-neuritic vitamine in the neighbourhood of 

 120° C. suggests that many tinned foods will be found deficient in, respect of 

 this constituent, and such we have found to be the case. We have examined 

 two samples of army " meat and vegetable ration." In order to concentrate 

 any vitamines they might contain, we extracted the air-dried material with 

 alcohol (see Cooper, 1913, and H. C. and E. M. H., loc. cit., p. 46), taking up 

 the residue, after evaporating the alcohol under redu.ced pressure, with a 

 small amount of water. In the case of Eation A, a very slight improvement 

 in symptoms, but nothing approaching a cure, was obtained after administra- 

 tion of an extract equivalent to 350 grm. (112 grm. dry weight), and in case 

 of Eation B, an incomplete cure after the equivalent of 440 grm. (106 grm. 

 dry weight). Working with fresh meat, and using a similar method. 

 Cooper (1913) obtained cures with the equivalent of 140 grm. ( = 30 grm. 

 dry weight). In the two preserved " rations there would therefore appear 

 to have been extensive destruction of anti-beri-beri properties during the 

 process of manufacture. 



Siovimary and Conclusions. 



1. Exposure of wheat embryo to a temperature of about 100° C. for two 

 hours resulted in no significant loss in anti-neuritic " vitamine." If, therefore, 

 it is included in the flour from which bread or biscuit is made, it can be relied 

 upon to retain its anti-neuritic properties after baking. 



