Page:George Archdall Reid 1896 The present evolution of man.djvu/144

132 produced by the force in the parent; but that it is asserted that this coincidence, this mere coincidence, must, from the nature of the case, be extremely rare—so very rare that, as factors in evolution, such apparent, but only apparent, transmissions of acquired traits may practically be ignored.

Epilepsy must depend on structural changes in nerve-matter, either gross changes, or molecular changes induced by alteration in the nutritive fluids, or by alterations in the nervous impulses received, or by spreading degenerative or inflammatory changes. If upon extended inquiry it were found that the structural changes in the nerve-matter of the offspring did not correspond to the structural changes in the nerve-matter of the parent, then this would be n0 true instance of the transmission of an acquired variation; for the epilepsy, though present in both parent and offspring, would be due to different causes. But if the structural changes in the offspring were found to be similar to those in the parent, it would have to be admitted that in this case an acquired variation had seemingly been transmitted; and the question would then arise as to the nature of the transmission, as to whether it was a true transmission of an acquired variation in the sense meant by those who contend that acquired variations are transmitted, i.e. as to whether it was transmitted because there is a tendency for acquired variations to be transmitted, owing to a power the organism possesses to so affect its germ cells that its acquired variations are reproduced in the offspring; or as to whether it was transmitted because this happened to be one of those very rare cases, those mere coincidences, in which the force which produced the acquired variation in the parent also produced directly or indirectly such changes in the germs, as caused in the organisms into which they proliferated inborn