Ants and Mites 
istic swelling, though not in such a pronounced form as 
was usual, He draws the obvious common-sense con- 
clusion that this rare characteristic of a swollen petiole 
probably owes its origin to the visits of ants continued 
for untold generations, until it has become a charac- 
teristic of the species. 
The well-known scientific society before whom the 
paper was laid, asked him to take out these conclusions 
of his, which were of course the really interesting and 
valuable part of the paper. Spruce never did so, and it 
has only appeared in a recently published book. 
It is difficult to understand why this course was 
taken ; even if Spruce had been proved wrong by other 
observations, his conclusions were a valuable piece 
of evidence which could have been tested by other 
naturalists. 
But then and even to-day there is a dogma which 
says that mutilations can never be inherited. Only 
to-day, after forty years, there are but few who believe 
it as firmly as was the case at that time. Spruce not 
unnaturally seems to have been disheartened and dis- 
gusted by this affair. Now of course we know of 
hundreds of ant plants which not only shelter swarms 
of ferocious ants but provide them with board as well 
as lodging. 
Some of these ant-plants produce sugary secretions, 
others “food-bodies,” which contain proteids. The 
reader will find much of great interest about ant-plants 
in Bates’ “ Naturalist on the River Amazon.” 
Perhaps the most striking of these plants are certain 
acacias which have huge swollen stipule-thorns which are 
hollow and form the residence. A minute hole gives 
entrance and exit to the ants. There is also the Imbauba 
or Cecropia, which has hollow internodes. At one point 
in the stem there is a very thin weak spot just towards 
207 
