STUDIES IN EUGENICS 23
intermarried during three consecutive generations in sufficient numbers to yield trustworthy results.
V. Literature. A vast amount of material that bears on eugenics exists in print, much of which is valuable and should be hunted out and catalogued. Many scientific societies, medical, actuarial, and others, publish such material from time to time. The experiences of breeders of stock of all kinds, and those of horticulturists, fall within this category.
VI. Co-operation. After good work shall have been done and become widely recognized, the influence of eugenic students in stimulating others to contribute to their inquiries may become powerful. It is too soon to speculate on this, but every good opportunity should be seized to further co-operation, as well as the knowledge and application of eugenics.
VII. Certificates. In some future time, dependent on cir- cumstances, I look forward to a suitable authority issuing eugenic certificates to candidates for them. They would imply more than an average share of the several qualities of at least goodness of constitution, of physique, and of mental capacity. Examina- tions upon which such certificates might be granted are already carried on, but separately; some by the medical advisers of insurance offices ; some by medical men as to physical fitness for the army, navy, and Indian services; and others in the ordinary scholastic examinations. Supposing constitution, physique, and intellect to be three independent variables (which they are not), the men who rank among the upper third of each group would form only one twenty-seventh part of the population. Even allowing largely for the correlation of those qualities, it follows that a moderate severity of selection in each of a few particulars would lead to a severe all-round selection. It is not necessary to pursue this further.
The above brief memorandum does not profess to deal with more than the pressing problems in eugenics. As that science becomes better known, and the bases on which it rests are more soundly established, new problems will arise, especially such as relate to its practical application. All this must bide its time; there is no good reason to anticipate it now. Of course, useful
