V ANTS AND PLANT-STRUCTURE 409 
Remarks by the Editor 
[The Director of the Kew Gardens, Lieutenant- 
Colonel Prain, informs me that the genus Tococa in 
cultivation produces the inflated bladders, but he 
does not know that the plant has ever been raised 
from seed, which is not produced in Europe. Prof. 
James W. H. Trail, who has observed these plants 
and the ants that infest them in Amazonia, informs 
him that in one or two cases plants which had no 
ants on them, though possessing the ant-dwellings 
moderately developed, were being damaged by 
herbivorous pests. This important observation 
indicates the ''utility" to the plant itself, which is 
always needed to bring natural selection into play 
for the purpose of modifying and rendering per- 
manent any special adaptation in plant- or animal- 
structure. 
Much light is thrown on this question by the 
observations of Mr. Henry O. Forbes, recorded in 
his Nahiralisf s Wanderings in the Eastern Archi- 
pelago (pp. 79-82). He found the strange tuberous 
Myrmecodia and Hydnophytum abundant in Sumatra 
and Amboyna (as they are all over the Archipelago), 
and raised many young plants from seed, which, 
though completely isolated from the ants that make 
their homes in the wild plants, grew vigorously and 
developed the internal branching cells and galleries 
from the very first. These chambers are formed by 
the shrivelling up of a delicate pith with which they 
are at first filled, and as they grow rapidly and form 
irregular tuberous masses as large as a man's head, 
it seems probable that this pith, as well as the 
watery liquid secreted in a large central chamber, 
