214 
s 
the increase of the mould material, it is desirable not to subject *) 
large quantities of uvie acid to this operation all at once, but to 
distribute it into a number of small flasks (containing not more than 
50 ee). Operating in this manner we prepared from 40 grams of 
uvie acid, distributed into 20 flasks, nearly 9 grams of pure /tar- 
tarie acid. 
The question, which is more of a biological than of a chemical 
nature, how the /tartaric acid is decomposed, could be answered 
by the determination of the above quoted assimilation quotient of 
the carbon, in that sense that it takes part, in the same degree as 
the d-acid, in the construction of the organism. This could not be 
proved in ‘a direct manner, because the pure /-acid promoted the 
growth of the inoculating material too slowly, but it could be 
determined from the values obtained in the growth on uvie acid 
compared with that of d-tartaric acid. 
The /acid is evidently attacked only a little slower. If we mix 
d-acid with uvie acid this will not much affect the absolute con- 
sumption of the /acid because the total amount of mould material 
formed in the same time will be approximately the same. As, howe- 
ver, we can only subject to the operation a solution not exceeding 
6°/,, the quantity of /-tartaric acid is smaller from the commence- 
ment and the yield will have to be low. If, for instance, we mix 
1'/, gram of d-tartarie acid with '/, gram of uvie acid, practically 
no “acid will be left when all the d-acid has disappeared. 
These experiments with Aspergillus were carried out in conjunction 
with others, because we had noticed that Penicillium glaucum, 
which was used for many of our observations exhibited towards 
the tartaric acids a but little pronounced power of selection. This 
will be seen at once from the subjoined table. 
The three acids behave nearly similar in regard to a same Penicil- 
lium culture; only during the first days the growth on the Lacid 
is somewhat less than on the two others. 
It seems remarkable that, in consequence of the great concentra- 
tion of the hydrogen ions, the retardation which in a 2°/, solution 
of /- and d-acid is very plainly perceptible after six days *) does not 
set in at all with the anti-acid. This is quite in harmony with the 
smaller dissociation constant of this acid*) owing to which, in a 
1) When using larger flasks, the surface in regard to the capacity is as a rule 
more unfavourable than when small flasks are used, so that the aeration becomes 
insufficient. 
2) BOESEKEN and Waterman. These Proc. 30 March 1912, p. 1112. 
3) Biscuorr and W axpen. Ber. D. Ch. G. 22, 1819 (1889). 
