obviously impossible to disprove either by means of the other, or by any class of facts to which they may severally appeal. I will give only one further example to show the elusiveness of Weismann's theory, and the consequent impossibility of finding any cases in nature which will satisfy the conditions of proof which the theory imposes. In one of his papers Weismann says that if there be any truth in the Lamarckian doctrine of the transmission of acquired characters, it ought to follow that the human infant should speak by instinct. For, ever since man became human he has presumably been a talking animal: at any rate it is certain that he has been so for an innumerable number of generations. Therefore, by this time the faculty of language ought to have been so deeply impressed upon the psychology of the species, that there ought to be no need to teach the young child its use of language; and the fact that there is such need is taken by Weismann to constitute good evidence in proof of the non-transmissibility of individually acquired characters. Or, to quote his own words, "it has never yet been found that a child could read of itself, although its parents had throughout their whole lives practised this art. Not even are our children able to talk of their own accord; yet not only have their parents, but, more than that, an infinitely long line of ancestors have never ceased to drill their brains and to perfect their organs of speech.... From this alone we may be disposed to doubt whether acquired capabilities in the true sense can ever be transmitted." Well, in answer to this particular case, we have first of all to remark that the construction of even the simplest language is, psychologically considered, a matter of such enormous complexity, that there is no real analogy between it and the phenomena of instinct: therefore the fact that Lamarckian principles cannot be applied to the case of language is no evidence that they do not hold good as regards instinct. Secondly, not only the construction, but still more the use of language is quite out of analogy with all the phenomena of instinct; for, in order to use, or speak, a language, the mind must already be that of a thinking agent; and therefore to expect that language should be instinctive is tantamount to expecting that the thought of which it is the vehicle should be instinctive--i.e. that human parents should transmit the whole organization of their own intellectual experiences to their unborn children. Thirdly, even neglecting these considerations, we have to remember that language has been itself the product of an immensely long course of evolution; so that even if it were reasonable to expect that a child should speak by instinct without instruction, it would be necessary further to expect that the child should begin by speaking in some score or two of unknown tongues before it arrived at the one which alone its parents could understand. Probably these considerations are