I have not found any further attempt in Professor Weismann’s book to deal with the evidence adduced by Mr. Darwin to show that mutilations, if followed by diseases, are sometimes inherited; and I must leave it to the reader to determine how far Professor Weismann has shown reason for rejecting Mr. Darwin’s conclusion.  I do not, however, dwell upon these facts now as evidence of a transmitted change of bodily form, or of instinct due to use and disuse or habit; what they prove is that the germ-cells within the parent’s body do not stand apart from the other cells of the body so completely as Professor Weismann would have us believe, but that, as Professor Hering, of Prague, has aptly said, they echo with more or less frequency and force to the profounder impressions made upon other cells.

I may say that Professor Weismann does not more cavalierly wave aside the mass of evidence collected by Mr. Darwin and a host of other writers, to the effect that mutilations are sometimes inherited, than does Mr. Wallace, who says that, “as regards mutilations, it is generally admitted that they are not inherited, and there is ample evidence on this point.”  It is indeed generally admitted that mutilations, when not followed by disease, are very rarely, if ever, inherited; and Mr. Wallace’s appeal to the “ample evidence” which he alleges to exist on this head, is much as though he should say that there is ample evidence to show that the days are longer in summer than in winter.  “Nevertheless,” he continues, “a few cases of apparent inheritance of mutilations have been recorded, and these, if trustworthy, are difficulties in the way of the theory.” . . .  “The often-quoted case of a disease induced by mutilation being inherited (Brown-Sequard’s epileptic guinea-pigs) has been discussed by Professor Weismann and shown to be not conclusive.  The mutilation itself—­a section of certain nerves—­was never inherited, but the resulting epilepsy, or a general state of weakness, deformity, or sores, was sometimes inherited.  It is, however, possible that the mere injury introduced and encouraged the growth of certain microbes, which, spreading through the organism, sometimes reached the germ-cells, and thus transmitted a diseased condition to the offspring.” {286}

I suppose a microbe which made guinea-pigs eat their toes off was communicated to the germ-cells of an unfortunate guinea-pig which had been already microbed by it, and made the offspring bite its toes off too.  The microbe has a good deal to answer for.

On the case of the deterioration of horses in the Falkland Islands after a few generations, Professor Weismann says:—­

“In such a case we have only to assume that the climate which is unfavourable, and nutriment which is insufficient for horses, affect not only the animal as a whole but also its germ-cells.  This would result in the diminution in size of the germ-cells, the effects upon the offspring being still further intensified by the insufficient nourishment supplied during growth.  But such results would not depend upon the transmission by the germ-cells of certain peculiarities due to the unfavourable climate, which only appear in the full-grown horse.”