I WRITE one more letter on this subject, in order to observe that I do not think the only remaining difference between Mr. Lloyd Morgan and myself is so great as it maybe apt to appear. In my books I have been careful to point out the peculiar disabilities under which the science of comparative psychology labours from its necessarily ejective character. But while in Mr. Morgan's view these disabilities are so great as to render any science of comparative psychology impossible, in my view they are not quite so great. I quite agree with the quotation which he gives from Prof. Huxley on the crayfish; but this does not amount to saying that no science of comparative psychology is possible. We may still, for instance, feel perfectly certain that a dog is a more intelligent animal than a crayfish, and in this we have a purely scientific proposition.