213 
of earbon determinations of the mould that formed on a definite 
organic compound used as exclusive carbon nutriment, while at the 
same time the amount of unattaeked substance in the nutrient base 
was determined. The further particulars of this research will be 
communicated by him elsewhere, when the significance of the survey 
thus obtained of the course of the plastic equivalent or assimillation 
quotient of the carbon*) will also be explained: here we will call 
attention to some observations on the growth of Aspergillus niger 
and Penicillium glaucum on the tartaric acids. 
Aspergillus niger grew hardly at all on /-tartaric acid, but very 
well on the d-acid, so that a 2°/, solution of the latter provided 
with the necessary inorganic nutriment was, after the lapse of six days 
used up by the mould. A 4°/, solution of uvie acid provided with 
0.15 °/, NH,NO,, 0.15°/, KH,PO, and 0.06°/, MgSO, and inocu- 
lated in the usual manner with Aspergillus niger and cultivated at 
33°—34° gave after six days a maximum /-rotation; this then 
began to decrease slowly, showing that the /-tartaric acid also gets 
consumed. 
This maximum rotation observed with the saccharimeter of Scamipt 
and HaenscH for white light in a 20 em. tube, amounted to — 1°,0 
corresponding with a solution of about 1,2°/, /-tartaric acid. 
As a 4°/, solution of uvic acid can only give at most a 1.88°/, 
solution of /-tartarie (on account of the disappearance of the d-acid 
and the water of crystallisation of the uvie acid) this maximum 
rotation corresponds with a yield of fully 60°/,. 
In order to isolate the /-tartaric acid the liquid after removal of 
the film of mould, was precipitated with lead acetate. The precipi- 
tate, after being washed was decomposed with hydrogen sulphide 
and the filtrate evaporated. 
From 4 grams of uvie acid was obtained 0.8989 gram of l-tartaric 
acid —56°/: 
The acid erystallises readily. 
0.100 gram consumed 8,6 ec. of baryta water of which 4.66 
were equivalent to 0.100 gram of salicylic acid: Mol. Weight = 
149.3 (calculated 150) 
0.2719 gram was dissolved in 50 ce. Polarisation in a 40 em. 
tube — — 0°.8, that is, for a solution in a 20 em. tube = — 1°,5, 
while a 2°/, solution of pure d-acid gave + 1.°6. 
As a part of the /-acid is consumed and as this is connected with 
1) Compare Waterman, Mutation with Penicillium glaucum ete. These Proc. 
29 June 1912, p. 124. 
