io6 Darwin, and after Darwin. 



observe, in passing, that this labour of testing Brown- 

 Sequard'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 fore- 

 going 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. 



In view of Obersteiner's corroboration of Brown- 

 Sequard 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 un- 

 known microbe" it indeed must be, which is always 

 on hand to enter a guinea-pig when certain operations 



