189 
ad. In which the blocks were kept moist with distilled 
water only. . 
e. In which the blocks were suspended in large beakers of 
distilled water, the surfaces of the blocks on which the 
yeast cells were situated being kept above the level of 
the liquid. 
In @ the only food material present was that contained in the 
few drops of beer-wort poured over the gypsum block, and in 
which the yeast cells had been actively growing: for 24 hours. 
In e a similar amount would be present’ at the start of the 
experiment, but by diffusion into the large quantity of distilled 
water contained in the beaker the cells would be practically 
denuded of all nourishment. 
With S. cereviscae an abundant supply of spores was obtained 
in @ and ¢; in c the number was fair; in 6 moderate; and in a 
none were formed. The number of spores produced for this 
species, then, was inversely proportional to the amount of food 
material present. 
In the case of S. anomalus, however, an opposite result was 
obtained. No spores were formed in é, while d, c, 6, and a 
formed an increasing series. | The number of spores in this case, 
then, was directly proportional to the amount of food material 
present. 
These results correspond well with certain facts that have 
already been observed in different cultures of the two species. 
S. cerevisiae forms no spores in streak cultures on various 
nutrient gelatine or agar media, nor in nutrient solutions. 
S. anomalus, on the other hand, forms spores abundantly in 
streak cultures on beer-wort gelatine, or agar, and also in solu- 
tions of various sugars. 
Klebs’ view, then, cannot hold for S. anomalus. It has been 
suggested that the variations in osmotic pressure might have 
something to do with these results. A series of cultures was 
therefore made, in which the gypsum blocks were moistened with 
solutions of KNO, (also NaCl) of different strengths. The 
solutions of KNO, and NaCl were of the following strengths :— 
10 ©6grams KNO, to 100 cc. of water. 
5 grams KNO, 
2°5 grams KNO, 
1:25 grams KNO, 
5 grams NaCl 
grams NaCl 
I'25 grams NaCl 
°65 grams NaCl . 
and control blocks moistened with distilled water in the case 
Se Se 
NO 
wat 
