much as can be done hopefully for many years in the selective breeding of individuals by the community as a whole. [Footnote: If at any time certainties should replace speculations in the field of inheritance, then I fancy the common-sense of humanity will be found to be in favour of the immediate application of that knowledge to life.] At present almost every citizen in the civilized State respects the rules of the laws of consanguinity, so far as they affect brothers and sisters, with an absolute respect--an enormous triumph of training over instinct, as Dr. Beattie Crozier has pointed out--and if in the future it should be found possible to divide up humanity into groups, some of which could pair with one another only to the disadvantage of the offspring, and some of which had better have no offspring, I believe there would be remarkably little difficulty in enforcing a system of taboos in accordance with such knowledge. Only it would have to be absolutely certain knowledge proved and proved again up to the hilt. If a truth is worth application it is worth hammering home, and we have no right to expect common men to obey conclusions upon which specialists are as yet not lucidly agreed. [Footnote: It has been pointed out to me by my friend, Mr. Graham Wallas, that although the State may not undertake any positive schemes for selective breeding in the present state of our knowledge, it can no more evade a certain reaction upon these things than the individual can evade a practical solution. Although we cannot say of any specific individual that he or she is, or is not, of exceptional reproductive value to the State, we may still be able, he thinks, to point out classes which are very probably, as a whole, _good_ reproductive classes, and we may be able to promote, or at least to avoid hindering, their increase. He instances the female elementary teacher as being probably, as a type, a more intelligent and more energetic and capable girl than the average of the stratum from which she arises, and he concludes she has a higher reproductive value--a view contrary to my argument in the text that reproductive and personal value are perhaps independent. He tells me that it is the practice of many large school boards in this country to dismiss women teachers on marriage, or to refuse promotion to these when they become mothers, which is, of course, bad for the race if personal and reproductive value are identical. He would have them retain their positions regardless of the check to their efficiency maternity entails. This is a curiously indirect way towards what one might call Galtonism. Practically he proposes to endow mothers in the name of education. For my own part I do not agree with him that this class, any more than any other class, can be shown to have a high reproductive value--which is the matter under analysis in this paper--though I will admit that an ex-teacher will probably do infinitely more for her children than if she were an