6/2 THE POPULAR SCIENCE MONTHLY. 



sistence ; it is tlieirs, as the chosen ministers of the higher ethics, 

 on the one hand, to counteract the life-destroying checks which 

 operate chiefly on the feeble and incompetent, and, on the other, 

 to inculcate the prudential considerations which are most influen- 

 tial with the finest types of mankind. No doubt the wider scope 

 which modern science has given to medical practice enables those 

 who pursue it to render services to the strong as well as to the 

 weak, and to compensate in some degree for the general lowering 

 of vitality which the maintenance of sickly lives tends to produce. 

 Sanitary improvements and the removal of many of the causes 

 of disease not only keep the infirm alive but insure increased 

 vigor to the constitutions of the robust. But still the result of 

 medical work as a whole at the present time must tend toward 

 the intensification and the thwarting of the struggle for existence 

 and perhaps to some deterioration of the species, for medical work 

 does intermeddle with Nature's rough and ready methods in 

 selecting her breeders. Great numbers of weakly infants who 

 would formerly have perished in their infancy are now reared to 

 a weakly maturity and enabled to propagate their weakliness (for 

 the weakly are often highly prolific), while they take part in the 

 life battle on terms sometimes made unduly favorable to them by 

 the commiseration that their weakliness commands ; and this fact 

 ought not to be lost sight of when we are congratulating our- 

 selves on our greatly diminished death-rate. An enormous sav- 

 ing of life has been effected, but mainly in life's earlier decades. 

 The death-rate is actually increasing among males at all ages 

 above thirty-five and among females at all ages above forty-five ; 

 and it is not difficult to prove that this increased mortality at 

 post-meridian ages is due partly to the enhanced wear and tear of 

 modern existence and partly to the survival of weakly lives arti- 

 ficially protected and prolonged. 



The origin of those moral sentiments which, in the case of our 

 race, are modifying the course of natural selection and which 

 have evoked and molded the profession to which we belong is as 

 inscrutable as the invention of natural selection itself, but their 

 development has some light thrown on certain of its stages by 

 biological considerations. In the life history of living organisms 

 we can trace out some rudimentary phases of a new struggle for 

 existence, a struggle between ethical princij^les and animal pro- 

 pensities, a struggle that has to be fought out in the brain and 

 mind of man, but that is foreshadowed in paltry protoplasmic 

 particles. For very early in organization may ethical rudiments 

 be detected ; indeed, the moment we get beyond the solitary cell, 

 a simple organism which merely feeds and grows and liberates 

 superfluous parts of its substance to start new organisms like 

 itself, mutual obligation or what might be called a moral relation 



