I am well aware that my scientific friends are some what puzzled to account for what they consider to be my delusion, and believe that it has injuriously affected what ever power I may have once possessed of dealing with the philosophy of Natural History. One of them — Mr. Anton Dohrn — has expressed this plainly. I am informed that, in an article entitled Englische Kritiker und Anti Kritiker des Darwinismus, published in 1861, he has put forth the opinion that Spiritualism and Natural Selection are incompatible, and that my divergence from the views of Mr. Darwin arises from my belief in Spiritualism. He also supposes that in accepting the spiritual doctrines I have been to some extent inﬂuenced by clerical and reli gions prejudice. As Mr. Dohrn's views may be those of other scientific friends, I may perhaps be excused for entering into some personal details in reply.