(303/2.

The reference is to Schmankewitsch's experiments, page 158: he kept Artemia salina in salt-water, gradually diluted with fresh-water until it became practically free from salt; the crustaceans gradually changed in the course of generations, until they acquired the characters of the genus Branchipus.) When I read imperfectly some years ago the original paper I could not avoid thinking that some special explanation would hereafter be found for so curious a case.

I speculated whether a species very liable to repeated and great changes of conditions, might not acquire a fluctuating condition ready to be adapted to either conditions.

With respect to Arctic animals being white (page 116 of your book) it might perhaps be worth your looking at what I say from Pallas' and my own observations in the "Descent of Man" (later editions) Chapter VIII., page 229, and Chapter XVIII., page 542.
I quite agree with what I gather to be your judgment, viz., that the direct action of the conditions of life on organisms, or the cause of their variability, is the most important of all subjects for the future.

For some few years I have been thinking of commencing a set of experiments on plants, for they almost invariably vary when cultivated.
I fancy that I see my way with the aid of continued self-fertilisation.
But I am too old, and have not strength enough.