When we turn to the question of the supposed transmission of acquired instincts and habits, we find that it is possible by means of the principle of selection, to explain some, at least, of the cases which presented difficulties to Darwin’s mind. Thus the tameness of rabbits, cats, and dogs, which animals have for countless generations been subjected to domestication, need not necessarily be accounted for by supposing that the results of training are transmitted. For it is easy to understand how those that would have rebelled most against man’s authority, and who were by nature the least tractable, would have been less cared for by man, and probably would finally have suffered extermination, while the docile received his attention, and were allowed to reach maturity and perpetuate the race. That this selection must be going on at the present time is very obvious, and as instances we may note the savage dogs that are constantly being destroyed, and the house dogs and domestic pets that are, in most cases, continually being selected from the docile animals and those of good temper. A dog that does not possess these good qualities can have no existence in town or village, and so by continual extermination of the unfriendly, the “friend of man” has gradually been evolved. _Paucity of Experimental Evidence of such Transmission._ Turning now to those cases in which characters can be acquired or experimentally stamped upon an individual, we find that no single reliable instance can be adduced in which transmission takes place. Mutilations have been practised upon male infants by Jews and other Semitic races for thousands of years; yet, in spite of this, the operation has still to be performed, for the lost parts appear in the offspring of to-day as in the earlier periods of their race’s history. Certain breeds of dogs and sheep have for many generations been systematically docked, and yet the young are born with as long tails as those of other breeds. Chinese women have compressed their feet from times long past in their history, yet Chinese female infants are still born with large feet, and have to undergo afresh the torture of their compression. More curious still, for it affects an organ of paramount importance, the brain, there is a tribe of Indians who flatten their heads in early life, entirely changing the shape not only of the skull, but of the brain itself, yet their children are born with normal rounded heads; the induced change is not transmitted. It must be admitted that this evidence is pretty strong, and we need not wonder that it has produced such widespread conviction, although it has been so lately taken up by the thinking public. _The Reproductive and the Body Cells._