212 
previously as to the direct nitration capacity of aliphatic carbon 
compounds, by nitrating malonie acid and its esters, methylene- 
tricarboxylic ester etc. from which it follows that the direct nitration 
capacity is caused by the adjacency of so-called negative groups of 
definite strength. 
In this manner were also discovered the aliphatic nitramines and 
nitramides, by nitrating the amides wherein occurs also a negative 
group and it now appears that an aliphatic secondary amine (dime- 
thylamine) may also undergo direct nitration when in the alkyl 
groups are present the group CN or CO,H, so distinctly negative 
groups. 
I, therefore, put to myself the question whether the phenyl or 
nitrophenyl-group ‘would also be able to give the same result as 
CN or CO,H. This, however, does not seem to be the case, for 
dibenzylamine HN (CH,C,H,), yielded only dinitrodibenzylamine nitrate, 
but no nitramine on boiling with absolute nitric acid. 
The ready nitration capacity of iminodiacetonitrile and of imino- 
diacetic acid and its derivatives is striking especially when we com- 
pare it with that of other substances as shown in the subjoined list. 
CH3.NH.CH3 not CN. CHs.NH. CH, . CN readily 
CH3. NH. CO. CH3 readily | CO‚H. CH>.NH. CH. CO H - readily 
CH3. CO. NH. COCH3 readily | CO .CH3.CH». NH.CH2.CO3,CH3 readily 
CH3. NH. CO,CH3 readily | CsH,(NO,)CH,.NH.CH,.CsHyNO» not 
CH3.CO.NH.CO.CH3 readily toe . NH. CH3 readily 
ie .CO,.NH. CO,CH3 not C5Ho(NO>)3 . NH . CgHo(NO>)3 not 
Biochemistry. — “A biochemical method of preparation of l-Tar- 
taric acid.” By Prof. J. Borsexen and Mr. H. J. WATERMAN. 
(Communicated by Prof. BeIJeRINCK). 
In our investigations on the assimilation of carbon nutriment by 
different kinds of mould it was found necessary to get some more 
information as to the manner in which the carbon was retained in 
the body of the plant either temporarily or permanently. 
For this purpose one of us (H. J. W.) carried out a large number 
