Behavior of Tubicolous Annelids 187 
as consciousness in ourselves.”? And in similar view Darwin dis- 
cusses in considerable detail the problems of plant heredity, both 
as to ontogeny and phylogeny, under the so-called “ Mnemic 
theory,” a theory recently developed by Semon and Rignano, 
though earlier advocated in substance by Hering and Butler. 
It is rather significant that at this same meeting, and before the 
Physiological Section of the Association, Dr. J. S. Haldane in his 
presidential address before the section assumed a similar attitude 
concerning fundamental problems of physiology. A single quo- 
tation may suffice to show the general attitude of this distinguished 
physiologist concerning the problems under review. “Now the 
first requisite of a working hypothesis is that it should work, and 
I have tried to point out that as a matter of fact the physico-chem- 
ical theory of life has not worked in the past and can never work. 
As soon as we pass beyond the most superficial details of physio- 
logical activity it becomes unsatisfactory; and it breaks down com- 
pletely when applied to fundamental physiological problems, such 
as that of reproduction. Those who aim at physico-chemical 
explanations of life are simply running their heads at a stone wall, 
and can only expect sore heads as a consequence.””® 
® Nature, October 1, 1908, p. 556. 
