TEACHERS DEPARTMENT. 
233 
tuberosum? To this end he made parallel cultures of two vari¬ 
eties of the common potato (Early Marjolin, and Lyon Giant) 
and of the S. commersoni. He first obtained a quantity of the 
mycelium of the endophyte by sterilizing the surfaces of slices 
of tubers of the Giant variety, and allowing the hyphae to de¬ 
velop until spores were formed. From these spores, which 
proved to be of a species of Fusarium, agreeing with the experi¬ 
ences of Bernard, he grew mycelium on other slices of sterilized 
potato. Certain tubers of each kind experimented with were in¬ 
fected with some of this mycelium at the time of planting, while 
others were left as they were. The soil was the same for all, 
as well as the time of planting and of digging up the tubers. 
The same numbers of infected and of non-infected tubers were 
planted in each case, and the weights recorded. From time to 
time single plants with all their underground connections were 
dug up, the tubers counted and weighed, the stolons counted and 
• measured, and the weights of the aerial portions noted. 
In the case of the Early Marjolin (the same variety as that 
with which Bernard had experimented) the yield of tubers com¬ 
pared to the weight of “ seed-potato ” was about twice as great 
with the infected plants as with the non-infected; while in the 
case of the other variety there was no notable difference either 
way. The artificial infection in the case of 5 '. commersoni pro¬ 
duced no constant results. With some individuals the tuberiza- 
tion seemed to be increased, while with others the reverse was 
true. In general, there seemed to be an increase in the number 
of stolons, but this influence did not continue through the season. 
It had been intended to use the mycelium of the fungus proper 
to this species of Solanum, but the author did not succeed in 
getting sufficient by artificial cultures. The tentative conclusions 
are that while infection does seem at first to produce an influence 
upon tuberization such as was pointed out by Bernard, this in¬ 
fluence is nevertheless not sufficiently great nor definite to involve 
absolute certainty without further investigation. 
According to the theory of M. I. Gallaud* the unsatisfactory 
* Gallaud, I. Etudes sur les Mycorhyzes Endotrophes. Rev. Gen. de 
Bot, 17: 5. 1905. 
