8th. Appearance of various morbid states of the skin and hair of the neck and face in animals born of parents having had similar alterations in the same parts, as effects of an injury to the sciatic nerve.
These results[64] have been independently vouched for by two of Brown-Séquard's former assistants--Dr. Dupuy, and the late Professor Westphal. Moreover, his results with regard to epilepsy have been corroborated also by Obersteiner[65]. I may observe, in passing, that this labour of testing Brown-Séquard's statements is one which, in my opinion, ought rather to have been undertaken, if not by Weismann himself, at all events by some of his followers. Both he and they are incessant in their demand for evidence of the transmission of acquired characters; yet they have virtually ignored the foregoing very remarkable statements. However, be this as it may, all that we have now to do is to consider what the school of Weismann has had to say with regard to these experiments on the grounds of general reasoning which they have thus far been satisfied to occupy.
[64] For Professor Weismann's statement of and discussion of these results see _Essays_, vol. i. p. 313.
[65] _Oesterreichische medicinische Jahrbücher_, 1875, 179.
In view of Obersteiner's corroboration of Brown-Séquard's results touching the artificial production and subsequent transmission of epilepsy, Weismann accepts the facts, but, in order to save his theory of heredity, he argues that the transmission may be due to a traumatic introduction of "some unknown microbe" which causes the epilepsy in the parent, and, by invading the ova or spermatozoa as the case may be, also produces epilepsy in the offspring. Here, of course, there would be transmission of epilepsy, but it would not be, technically speaking, an hereditary transmission. The case would resemble that of syphilis, where the sexual elements remain unaffected as to their congenital endowments, although they have been made the vehicles for conveying an organic poison to the next generation.
Now it would seem that this suggestion is not, on the face of it, a probable one. For "some unknown microbe" it indeed must be, which is always on hand to enter a guinea-pig when certain operations are being performed on certain parts of the nervous system, but yet will never enter when operations of any kind are being effected elsewhere. Moreover, Westphal has produced the epilepsy _without any incision_, by striking the heads of the animals with a hammer[66]. This latter fact, it appears to me, entirely abolishes the intrinsically improbable suggestion touching an unknown--and strangely eclectic--microbe. However, it is but fair to state what Weismann himself has made of this fact. The following is what he says:--