128 
TABLE 
200 cc, ERLENMEIJER-flasks of Jenaglass with 50 cc. tapwater, in which 0.05 9/) NH,CI 
0,05 9) KH, PO,, 0,02°/) MgSO, and 150 mgr. para-oxybenzoic acid, 
temperature about 32°—33°. 
Form | Form II Form III 
Plastic aequivalent of the 29 0/, 18 % 15 % 
carbon in two experiments 28 0, 18 0/, 16 0% 
the here described mutation a loss of characteristics or gens, for 
beside the loss in colour intensity we stated a decrease in the 
number of spores. 
On the other hand it was observed, that the new forms were dis- 
tinguished from the primitive one by a much more vigorous combustion 
of the p-oxybenzoie acid to carbonic acid, their “respiration aequi- 
valent” being found to amount from 71—72°/, in I, to 82 °/, in II, 
and even to 85 °/, in III. 
If, as in the case observed, all other carbon-containing secondary 
products are wanting, the sum of the two aequivalents is of course =100. 
The here introduced aequivalents only relate to the element carbon, 
whereas the hitherto used coefficients refer to the number of grams 
of dry substance, to the number of grams of assimilated carbon, or 
to the carbonic acid evolved during the life of the related organism *). 
The here introduced aequivalents are to be preferred to the other 
terms referred to, because the chemical composition of the food, of 
the constituents of the organism, and of the carbonic acid are so 
widely divergent. 
Finally I bring my thanks to Mr H. C. JacoBseN, assistant to the 
Laboratory for Microbiology, for his kind help in these experiments. 
Laboratories for Microbiology and Organic Chemistry 
of the Technical Unwersity at Delft. 
1) See for instance: KUNSTMANN, Ueber das Verhältnis zwischen Pilzernte und 
verbrauchter Nahrung. Dissertation Leipzig, 1895. Also: Naruansonn, Stoffwechsel 
der Pflanzen, 1910. 
