345 
organism, in a state of nature, enjoys the opportunity of performing 
all that it is capable of doing. The constant struggle for existence, 
or whatever phrase be preferred, that compels every animal and 
plant to be content with the mean, or give and take policy, prevents 
the accomplishment of such an ideal. Even the fittest, judged from 
the standpoint of number of individuals and distribution in space, 
are amendable to opportunity. If this argument be sound, it follows 
that the extension of disease amongst cultivated plants, nay even 
the creation of new diseases, due to fungi, should be great, as the 
opportunities indirectly and unknowingly, to most people, are many 
and far reaching. As it has been abundantly demonstrated, that 
the education of a saprophytic fungus to change its nature, an 
become a rampant parasite, is a simple matter in the laboratory, it 
may be assumed that when facilities are offered outside the labora- 
tory the same change would be effected. Among such opportuni- 
ties for ordinarily saprophytic fungi to change their mode of life 
may be mentioned the constant wounding of plants, due to 
careless planting, “ heeling in,” 
roots, pruning, &c. The principal reason why there are no 
epidemics due to fungi in virgin forests and uncultivated places 
period of time, a a process of elimination the survivors are 
able to live side by side without either being capable of exercising 
very ma superiority. On han: 
an 
he worm usually escapes from the egg in the gall, and is a tiny 
