213 
by the Agency of Insects . 
Regarding the first question, the action on the fly, there 
was no deleterious effect. They lived for about three weeks 
on this food and then died, and as was to be expected no sub- 
sequent change occurred in their bodies. 
With respect to the second question, the effect on the spores, 
it was found in the first place, by microscopical examination, 
that thousands of spores clung to the feet and proboscides of 
the flies. These would obviously retain their vitality. The 
excrements of the flies which soon covered the inside of the 
box, at first consisted chiefly and then exclusively of spores, 
microscopically indistinguishable from those directly removed 
from the gleba. 
It was thus clear that the flies transported the spores, but 
the question was still to be decided whether the spores re- 
tained their vitality after passing through the digestive system 
of the insect, or whether, on the other hand, it was destroyed. 
On a priori grounds this question would be answered in the 
affirmative. The rapid mimetic changes in the hymenium, 
the luring of large numbers of flies, and the fact that the flies 
carry off the great majority of the spores which they sub- 
sequently deposit, all point to adaptation ; and to suppose that 
the vitality of the spores was destroyed would be to assume 
that a species might with impunity offer facilities for its own 
extinction. To experimentally determine the point, I adopted 
the following method for the germination of the spores. A 
quantity of earth taken from the place where the fungus grew 
was sterilised by prolonged boiling, and two series of open 
glass tubes were filled with this and with certain substances as 
shown in Table I. One tube in each series contained the same 
material, and to all those of one series was added the spori- 
ferous deposit of the flies. Thus each experiment was dupli- 
cated, the only factor of difference being that in one series (A) 
the flies’ excrements were present, and in the other series (R) 
absent. The tubes were then closed with cotton-wool and 
buried vertically, eight inches apart, in the locality were 
Phallus impudicus grew, near the surface but quite covered 
with the soil. This was done in September, and in the follow- 
