130 



SCIENCE 



[N. S. Vol. XXVI. No. 657 



was pondering his theor}^, Logan and the 

 New York geologists were studying and 

 giving names to strata antedating the 

 primordial animals and in the fifty years 

 since not only has the theory of the crea- 

 tion of species by generation advocated by 

 Darwin won practically universal scientific 

 acceptance, but many thousand feet of 

 rocks laid down before the Paleozoic have 

 been much studied.^ One might infer that 

 discoveries in these beds had removed the 

 difficulties. This is not true. The Dar- 

 winian theory has won acceptance by its 

 marshaling of facts in other lines. The 

 most serious difficulty still remains most 

 serious. The years have indeed brought 

 so many connecting links to light since 

 Paleozoic time that we may reasonably ex- 

 pect to find more, and in view of the im- 

 perfections in our knowledge of the geo- 

 logical record and the fact emphasized by 

 Rice last winter that the record itself is 

 likely to be particularly imperfect just at 

 the critical and exciting parts of the story 

 of life, the lack of more such links seems 

 no longer very serious. 



On the other hand, the difficulty at the 

 beginning has in some ways increased. 

 Beds before the primordial, but little 

 altered, such as later preserve ample traces 

 of life— black slates, limestones, dolomites 

 — show only obscure traces. 



Nor does the total thickness of such beds 

 suggest a time before the Paleozoic longer 

 than that since. Astronomers and physi- 

 cists are putting limits to the age of the 

 earth, which though ample for the deposi- 

 tion of all known sediments, curtail the age 

 of the planet as an abode for life to a 

 number of years which the Paleozoic and 

 later beds may easily have taken to form. 

 At the same time the discovery of fishes 

 in the Ordovician shows that the tree of 



^The latest fruit being the report of the Adi- 

 rondack Committee, Jour. Geol., 1907, pp. 1&1-217. 



Life had developed all its main branches at 

 that early date. Where then and how did 

 early life manage to do this "90 per cent." 

 of its differentiation so quickly or with so 

 little trace of itself 1 



Besides the answer suggested by Darwin 

 which seems no longer admissible— it was 

 proposed by him with the greatest reserve 

 —three notable suggestions have been made 

 toward lessening the difficulty. I refer to 

 those of Brooks, Chamberlin and Daly. 



Bi'ooks imagines that the early forms of 

 life Avere free-swimming surface forms of 

 the deep sea, not freely preserved until 

 they discovered the shore as a habitat. 



Chamberlin suggests, on the contrary, 

 that the early life was developed in fresh 

 water, in streams and landlocked waters. 

 Dwellers in such locations have rarely left 

 any trace of themselves, in the rocks. 

 Fresh water dissolves their shells, while the 

 deposits themselves are liable to frequent 

 rehandling. 



Daly has recently suggested that the 

 chemical character of the water was the 

 determining factor, and that (during 

 Eozoic time) the ocean was limeless so that 

 the animal could not secrete hard parts. 



I will not just here go into any elaborate 

 discussion of these theories and the argu- 

 ments for and against. They are not com- 

 patible. Each has almost obvious dif- 

 ficulties, and it is clear that farther light 

 will be very welcome. I wish first to call 

 attention to a ray of light which the 

 geologist might easily overlook, since it is 

 due to a physiologist, one of the assistants 

 at the College de France, R. Quinton. He 

 has written a brilliant book of some 500 

 pages^ to defend the thesis which he had 

 proposed in 1897 that the higher animals 

 show traces in the vital fluid of their orig- 

 inal environment. Let me explain. 



' " L'Eau de Mer Milieu Organique,' 

 Paris, 1904. 



Masson, 



