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 Naturalist's Wanderings in the Eastern Archi- 

 pelago (pp. 79-82). He found the strange tuberous 

 Myrmecodiaand 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, 



