War always changes the composition of a nation; but this change may be either a loss or a gain. The modification of selection by war is far more manifold than the literature on the biological effects of war would lead the reader to suppose. All wars are partly eugenic and partly dysgenic; some are mainly the one, some are mainly the other. The racial effects of war occur in at least three periods:
1. The period of preparation.
2. The period of actual fighting.
3. The period of readjustment after the war.
The first division involves the effect of a standing army, which withdraws men during a part of the reproductive period and keeps most of them in a celibate career. The officers marry late if at all and show a very low birth-rate. The prolonged celibacy has in many armies led to a higher incidence of venereal diseases which prolongs the celibacy and lowers the birthrate.[155] Without extended discussion, the following considerations may be named as among those which should govern a policy of military preparedness that will safeguard, as far as possible, the eugenic interests:
1. If the army is a standing one, composed of men serving long terms of enlistment, they should be of as advanced an age as is compatible with military efficiency. If a man of 35 has not married, it is probable that he will never marry, and therefore there is less loss to the race in enrolling him for military service, than is the case with a man of 20-25.
2. The army (except in so far as composed of inferior men) should not foster celibacy. Short enlistments are probably the most valuable means of avoiding this evil.
3. Universal conscription is much better than voluntary service, since the latter is highly selective, the former much less so. Those in regular attendance in college should receive their military training in their course as is now done.
4. Officers' families should be given an additional allowance for each child. This would aid in increasing the birth-rate, which appears to be very low among army and navy officers in the United States service, and probably in that of all civilized countries.
5. Every citizen owes service to his nation, in time of need, but fighting service should not be exacted if some one else could perform it better than he where he is expert in some other needed field. The recent action of England in sending to the front as subaltern officers, who were speedily killed, many highly trained technicians and young scientists and medical men who would have been much more valuable at home in connection with war measures, is an example of this mistake. Carrying the idea farther, one sees that in many nations there are certain races which are more valuable on the firing line than in industries at the rear; and it appears that they should play the part for which they are best fitted. From this point of view, the Entente allies were wholly justified in employing their Asiatic and African subjects in war. In the United States are millions of negroes who are of less value than white men in organized industry but almost as valuable as the whites, when properly led, at the front. It would appear to be sound statesmanship to enlist as many Negroes as possible in the active forces, in case of war, thus releasing a corresponding number of more skilled white workers for the industrial machine on whose efficiency success in modern warfare largely rests.