circumstances tend to show that the individual and the transmissible type are independent of each other so far as modifications of parts are concerned.

It may seem natural to expect the transmission of an enlarged muscle or a cultivated brain, but, on the other hand, why should it be unreasonable to expect that a modification which was non-congenital in origin should still remain non-congenital? Why should the non-transmission of that which was not transmitted be surprising?

Mr. Spencer thinks that the non-transmission of acquired modifications is incongruous with the great fact of atavism. But the great law of the inheritance of that which is a development of the transmissible type does not necessarily imply the inheritance of modifications acquired by the individual. Because English children may inherit blue eyes and flaxen hair from their Anglo-Saxon ancestors, it by no means follows that an Englishman must inherit his father's sunburnt complexion or smooth-shaven face. Of course atavism ultimately adopts many instances of revolt against its sway. But to assume that these changes of type follow the personal change rather than cause it, is to assume the whole question at issue. That like begets like is true as a broad principle, but it has many exceptions, and the non-heredity of acquired characters may be one of them.