May, 1907 ORNITHOLOGY FOR A STUDENT OF EVOLUTIONARY PROBLEM.S 71 



I close with a single reflection on the outlook of biological generalization of 

 the day. At no time during the last twenty-five years have evolution hypotheses 

 been so up in the air as just now. A few writers believe that the idea of evolution 

 itself is going to smash. Sober, well-balanced naturalists are not skeptical to this 

 extent. Many of them are, however, disposed to settle down to the view that 

 search after a method by which species originate is time wasted simply because 

 there is no such a thing. There are many factors, they say, in evolution, and 

 biology has done all incumbent upon it when it has found out what they are. Cer- 

 tain it is now that there are various factors in species production, and it is a great 

 achievement to have unearthed so many of them. Natural selection is a widely 

 operative factor; so is sexual selection; so is orthogenesis; so is isolation; so, quite 

 certainly, is mutation. The list, were it complete, of more or less distinct, more or 

 less efficient, factors would be much longer. I ask are we to rest here? Having 

 corralled t\\^'^Q factors, are we going to wr'iX.^ Jjuis over the gate of the corral? Not 

 if biological motive is true to itself. Does not your mind and mine, and every 

 mind that is in the habit of thinking at all, start off immediately and unrestrain- 

 ably, the last factor having been lodged in the corral, in quest of some one or at 

 least a less number of factors or principles underlying those already captured? If 

 species are fully produced by so many different causes, different combinations of 

 these operating together in different groups of plants and animals, how do we 

 know that species have anything in common? Is it a tenet of biology or any 

 other physical or spiritual science that unlike causes produce like results? And if 

 you are not certain that all species have something in common, what justification 

 have you in attempting to treat them all alike in classification ? What is the good 

 of bothering about uniform rules of nomenclature if the rules are to apply to differ- 

 ent things? But are we not warranted in believing, nay, are we not compelled by 

 the totality of biological data to believe that there is more unity in evolution than 

 all these factors indicate? Is there not fundamentality in the metabolic processes 

 of organisms? Is not this true also of response to stimulus? Is it not true of re- 

 production ? Has not the cellular theory of organization a unifying principle in it 

 that is about the securest of all biological generalizations ? 



It is, I am confident, only stating what every thoughtful naturalist assents to 

 without hesitation to say that the goal of, biology — not a remote, but the immediate, 

 animating goal — is greater unification of its knowledge. Minds can never rest 

 from the search for deeper, more inclusive principles. This brings our evening's 

 discussion to a close at the point from which it started. 



University of Catifornia, Berkeley, California. 



THE BIRD ISDANDS OF SOUTH AFRICA ^ 

 By W. L. vSCLATER M. B. O. U. 



ONE of the most remarkable forms of bird life at present existing is certainly 

 the group of Penguins. These birds, which constitute the Order Ini- 

 pennes, stand wide apart from all the other living Orders of birds not only 

 in their structure but also in their life history and distribution. They are the only 

 birds in which the metatarsal bones of the adult show plainly their threefold 

 origin, the bones in question being short and separated by deep grooves. The 



I The spelling and capitalization in this article accord with the request of the author. 



