1352 
b. Sulfur. The results of the experiments on the action of different 
sulfate concentrations are found in Table II. 
Here we see that in the culture tubes (N° 1), where no sulfur was added, 
development takes place, just as had before been observed for the nitro- 
gen, the fosfor, and the potassium. A considerable spore formation took 
place after 2 days already in Nrs. 1—7, which had a deficiency of sulfur, 
whilst in the experiments with more sulfur the production of spores 
was at first slackened. Nrs. 8—20 had only few spores. After 3 
days Nrs. 14—20 had hardly any, whilst in all other culture tubes 
an important spore formation had already occurred. After 4 days 
these differences were less marked; after 40 days all the mould 
layers were covered with a considerable number of spores. The 
explanation of this temporary inhibition of the spore production is 
the same as for the elements treated before. In other respects, too, 
the sulfur quite corresponds with the other elements. Like the carbon, 
nitrogen, and fosfor, the sulfur accumulates in the cells and is after- 
wards partly excreted. 
Indirectly this could already be shown by the following consider 
ations. 
We see that in Nr. 8, after 3 days only 34,5°/,, after 3 days 
in Nr. 9, 36°/,, after 40 days already 48°/, of the glucose has been 
assimilated, notwithstanding after 3 days no sulfate was left in the 
solution. Evidently during the development of the organism by the 
dissimilation of an intermediary product, sulfate is set free in the 
liquid so that the assimilation of the glucose can go on. This is 
still more obvious in Nrs. 11—13. After 3 days the assimilation of 
the glucose was 49°/,, after 4 days it mounted to 61°/,, and after 
40 days already 82°/, of the glucose had been used, whereas, here 
too, after 3 days already, all the sulfate had disappeared from the 
solution. By direct analysis was shown that an old, mature mould 
layer indeed contains less sulfur than a young one obtained in quite 
the same way and under the same conditions. 
To this end the mould was, after frequent washing with distilled 
water, destroyed by fuming nitric acid, in a closed tube at 300° C. 
The sulfate was precipitated in the usual way. 
It was here proved that of 4 mature mould layers (70 and 40 
days old), treated in this way, after 3 to 4 hours’ heating on alow 
flame, no precipitate was formed, whereas 4 young moulds (3 and 
4 days old)”, likewise treated, did give a precipitate after heating. 
In what condition the sulfur, temporarily withdrawn from the liquid, 
exists in the organism, must for the moment be left undiscussed. 
*) These were the mould layers of Nrs. 14, 18, 15, 16 (Table II). 
