ON BIOLOGY. 87 



the way in which they rear their young:, and everything 

 that pertains thereto; and, finally, statistics as to what 

 economical value it may possess, and other matters. So it 

 will be seen that, in the case of any species of mammal, to 

 give a complete account of its life-history in a thoroughly 

 scientific manner is far from being alight task. But this 

 is by no means all I would exact of the zoologist, for such 

 hisiorical accounts, to be of the greatest value, should be 

 made comparative in every sense of the word. Habits 

 and all the other matters I have just enumerated, having 

 been collected for the most lowly organized types of the 

 mammals of any particular family or group, should be 

 properly compared with the corresponding traits as found 

 in the animals next above them in the same group. Then 

 the digested data, the outcome of such studies when 

 systemized, should, in turn, be compared with the simi- 

 lar and comparable knowledge derived from like observa- 

 tions upon the next most nearly affined group or family 

 of mammals, and that, too, the next higher in the scale 

 of organization. 



Thus it should be carried on and upward through the 

 system, from the most lowly organized types to include 

 the various genera of new and old world apes and their 

 near kin. As we ascend step by step we should be par- 

 ticularly careful to note any new habit that may arise, 

 especially those habits which appear to* indicate any ad- 

 vance in the mental faculties, or kindred attributes. 

 With such knowledge at our command, and systemat- 

 ically formulated for proper use we are in a position to 

 undertake identically the same kind of studies in the 

 case of all the various types and races of men, or the 

 world's anthropofaunae, beginning with the very lowest 

 types of man known to us and ascending the scale to 

 those most highly organized in all particulars physic- 

 ally, mentally, morally and intellectually. It is very 

 desirable that this should be done, done well, and made 

 thoroughly comparative. A great deal has been done 

 already along such lines, but in my estimation very little 

 in comparison with what is actually required. By such 

 studies much light may be thrown upon the question of 

 the origin of the mental powers in man; the tracing of 

 the origin of language, and of the special development of 

 the intellect; of the origin and development of the moral 

 qualities; of certain desires and passions; of the relations 

 of the sexes; origin of marriage; and, finally, a great deal 

 else which may be said to be the natural outcome of the 

 development of all that is included in the social instincts 



