RELATION BETWEEN VEGETATIVE VIGOR AND REPRODUCTION 559 
The weight of mycehum out of solution number 6 is practically the 
same as that out of number 2. When salts are added to peptone and 
sucrose the number of oogonia produced is materially increased and 
the weight is much greater than from solutions without salts. As 
before suggested, this is probably due to the formation of invert sugar 
from the sucrose by the action of high temperature and salts. 
There is evidently no relation between weight of mycelium and 
number of oogonia even when the record of numbers 2 and 3 is dis- 
carded. The weight of mycelium was about equal out of solutions 
4, 7 and 9 but the number of oogonia varied from 58 on mycelium out 
of solution 7 to 119 out of solution 9. Again, mycelia out of solutions 
15 and 17 show practically the same weight but vary in the number of 
oogonia recorded from 52 to 103. For vegetative growth S. monoica 
does not use dextrose as freely as it does maltose and levulose, agreeing 
in this with S. ferax. The difference in weight is striking and appears 
consistently in all the records, but it is doubtful whether it is safe to 
draw more than the most general conclusions from the record of the 
number of oogonia, since this species produces oogonia more readily 
and abundantly than any other species the writer has isolated. In 
general, however, the conclusions previously drawn seem warranted 
by the results of this experiment also. The minimum food required 
for an abundant supply of oogonia is less than that demanded by 
5. ferax, the critical concentration evidently being below o.i percent 
peptone, but there is no uniform relation between weight of mycelium 
and number of oogonia. The value of levulose is also confirmed. 
Klebs found that when S. mixta was placed in 0.05 percent haemo- 
globin oogonia were readily formed but they were not accompanied by 
antheridia. With the same treatment 5. monoica gave similar results 
although some oogonia with antheridia were always present. The 
number of oogonia accompanied by antheridia was determined by 
counting 100 or 200 or sometimes a larger number of oogonia under a 
16 millimeter objective and recording the number to which antheridia 
were attached. While the figures cannot be considered final there is a 
consistent trend toward an increase in the number of antheridia when 
the culture medium has contained a form of invert sugar, especially 
levulose. Number 14 is the only exception to this. In this solution 
much of the sucrose was probably converted into invert sugar and if 
so the number of antheridia should approach that in the case of the 
solutions with invert sugar. The larger number of antheridia present 
