TRANSMISSIBILITY OF FUNCTIONAL MODIFICATIONS 67 



occur in breeds whose tails have not suffered from the fashion of 

 docking, as, for instance, in the Dachshund. 



We may therefore affirm tliat an inheritance of artificially pro- 

 duced defects and mutilations is quite unproved, and in no way bears 

 out the supposed inheritance of functional changes. 



This is now admitted by the great majority of the adherents of 

 the Lamarckian principle, and we may now regard this kind of ' proof ' 

 as disposed of. 



In addition to the above, various sets of facts have been Vjrought 

 forward as proofs, and in particular the mucli discussed experiments 

 of Brown-Sequard on guinea-pigs, from which it was inferred that 

 e2:)ilepsy artificially induced could be transmitted. But these experi- 

 ments do not really prove anything in regard to the question at issue, 

 because epileptic-like convulsions may have very various causes, and 

 these are, for the most part, quite unknown. Since artificial epilepsy can 

 be induced in guinea-pigs by the most diverse injuries to the central 

 or peripheral parts of the nervous system, this of itself points to the 

 fact that it is not a question of the mere lesion of anatomical structure, 

 I mean, of the breaking of the continuity of a definite part, and of 

 its transmission. The result would, in any case, difier according 

 to whether certain centres of the brain, or half the spinal cord, or 

 the main nerve-trunks were cut through. There must, therefore, be 

 something more needed to produce the appearance of epilepsy — 

 some morbid process which may arise at different parts of the nervous 

 system, and be continued from them to the brain-centres. This is 

 corroborated by the fact that it takes at least fourteen days, and 

 often from six to eight weeks, for epilepsy to develop after the 

 operation, and that in many cases it does not develop at all. I have 

 made the suggestion that, during or after the operation, some kind of 

 pathogenic micro-organism might easily reach the wounded parts, 

 and there excite inflammation, which may extend centripetally to the 

 brain. Similar processes have been observed in connexion with lympli- 

 vessels, and why should they not occur in connexion with nerves ? 



It has been objected to this that the guinea-pig's epilepsy may be 

 produced by blows on the skull, and also by a destructive compression 

 of the nerviis ischiadictis through the skin, and that in both cases the 

 epilepsy may reappear in the following generation ; and this, it is sup- 

 posed, shows that the intrusion of microbes is excluded. If this were so 

 beyond a doubt, and if we could exclude the possibility that there 

 were previously various microbes within the body, whicli could onl}" 

 penetrate into the nervous substance after the cutting or destruction 

 of the neurilemma, nothing would be gained that would in any way 



F rz 



