Page:Supplement to harvesting ants and trap-door spiders (IA supplementtoharv00mogg).pdf/32

 rising from the acid might be noted. Similar seeds were sown at the same time and in the same way, but without the acid, so as to permit of comparison. These experiments have afforded some interesting results, but do not supply any positive data which might help us to discover the secret of the ants. They narrow, indeed, the area in which search can profitably be made, indicating as they do that the vapour of formic acid is incapable of rendering the seeds dormant after the manner of the ants, and showing, on the contrary, that its influence is always injurious to the seeds, even when present only in excessively minute quantities.

It appears to me now that the most promising field for experiments made with a view to clearing up this difficulty, is that afforded by the closer investigation of the phenomena of normal germination, and by a study of the conditions under which seeds remain dormant, as they are occasionally known to do, in situations which our general experience would have selected as favourable to germination.

I have good hopes, also, that when we come to know more of the habits of harvesting ants in tropical countries, and when naturalists have excavated and described their subterranean stores—a thing which has not yet been done as far as I know—we may gather fresh indications to guide us in our search.

I am puzzled to account for the fact, which I have seen stated by more than one observer in India, that