But, interesting and suggestive as this experiment is in other connexions, it is clearly without significance in the present one, for the reason already stated. It will have to be tried on well-marked varieties of other species of animals, which are known to throw intermediate characters. Even, however, if it should then yield a similarly negative result, the fact would not tell against the inheritance of acquired characters; seeing that an ovum by the time it is ripe is a finished product, and therefore not to be expected, on any theory of heredity, to be influenced as to its hereditary potentialities by the mere process of gestation. On the other hand, if it should prove that it does admit of being thus affected, so that against all reasonable expectation the young animal presents any of the hereditary characters of its uterine mother, the fact would terminate the question of the transmission of acquired characters--and this quite as effectually as would a similarly positive result in the case of progeny from an ingrafted ovary of a different variety. In point of fact, the only difference between the two cases would be, that in the former it _might_ prove possible to close the question on the side of Lamarckianism, in the latter it would _certainly_ close the question, either on this side or on the opposite as the event would determine. The only additional fact that has hitherto been published by the school of Weismann is the result of Weismann's own experiment in cutting off the tails of mice through successive generations. But this experiment does not bear upon any question that is in debate; for no one who is acquainted with the literature of the subject would have expected any positive result to follow from such a line of inquiry. As shown further back in the text, Darwin had carefully considered the case of mutilations, and explained that their non-transmissibility constitutes no valid objection to his theory of pangenesis. Furthermore, it may now be added, he expressly alluded in this connexion to the cutting off of tails, as practised by horse-breeders and dog-fanciers, "through a number of generations, without any inherited effect." He also alluded to the still better evidence which is furnished by the practice of circumcision. Therefore it is difficult to understand the object of Weismann's experiment. Yet, other than the result of this experiment, no new fact bearing on the question at issue has been even so much as alleged. CHAPTER VI. CHARACTERS AS HEREDITARY AND ACQUIRED (_conclusion_[84]). [84] _See_ note appended to Preface. C. Ll. M.