Page:George Archdall Reid 1896 The present evolution of man.djvu/143

Rh acquired an epileptic habit, such that a pinch on the neck would produce a fit, inherited an epileptic habit of the kind. It has, indeed, been since alleged that guinea-pigs tend to epilepsy, and that phenomena of the kind described occur where there have been no antecedents like those in Brown-Sequard's case. But considering the improbability that the phenomena observed by him happened to be nothing more than phenomena which occasionally arise naturally, we may, until there is good proof to the contrary, assign some value to his results."—The Factors of Evolution. Williams and Norgate: 1887.

But if it is true that epilepsy usually supervenes in guinea-pigs when the sciatic is severed, and that this acquired epilepsy is generally or even occasionally inherited by the offspring, there appears to be strong grounds for supposing that the acquired variation in this case is transmissible. But before we could positively decide as to this we should have to still further extend our inquiry.

But here the reader must be reminded of that which was insisted on in a former page, namely, that in the last analysis all inborn variations in any organism must be due to acquired variations in the germ cell from which it arose. He must remember that it is not denied that a force acting on an organism may produce changes in its germ cells, and consequently in the descendant organisms; but that it is denied that the changes produced in the germ cell are usually such that in consequence of them they tend to grow into organisms in which appear changes similar to the changes produced by the force in the parent organism. He must remember that it is not asserted that a force acting on an organism cannot produce such a change in the germ as will cause the organism into which it develops to exhibit a variation similar to the variation