ASPARTATES AND MALATES 21 



rotary power. Like the tartaric acid it carries over this 

 last property into its solutions, whether acid or alkalin, 

 but it presents this unforeseen pecuHarity of rotating to 

 the left the plane of polarization when it is in a neutral 

 or an alkalin solution, and on the contrary of rotating 

 it to the right, and to a much greater extent, when it is 

 in an acid solution. In no case, however, has it ceased 

 to be asparagin unless the liquid has been heated or 

 the acids or alkalies have been too concentrated, and it 

 is possible by precipitation to recover it with all the old 

 properties. This proved that the rotary power of a 

 substance did not depend on itself alone and that if the 

 existence of this power had any significance for the ideas 

 on which Pasteur had taken his stand, its meaning and 

 importance were contingent and of a secondary order. 



I have just said that, in order to leave intact the as- 

 pai'agin on which one is working, it is necessary not to 

 heat the liquids. Boiled with an alkalin solution, it is 

 transformed into aspartic acid. Does this acid keep 

 any of the rotary power of the asparagin? It is too little 

 soluble in water to make it possible to study it in aqueous 

 solutions. In solution in the alkahes it rotates to the 

 left: in chlorhydric or nitric acid it rotates to the right. 



Another derivative of asparagin was still more interest- 

 ing to study; viz., the malic acid which one can obtain 

 from it by action of hyponitric acid. This malic acid 

 accompanies tartaric acid in the grape and therefore 

 should arouse curiosity. Experiment shows that in 

 regard to the rotary power it behaves a little like tartaric 

 acid, and that it sometimes even recalls it so much in its 

 properties that one is tempted to suppose for the two 

 acids origin from a common atomic grouping. Never- 

 theless, in their ensemble, the phenomena presented by 

 malic acid and the malates are more complicated than 

 those of tartaric acid and the tartrates. In the latter 



