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THE AUSTRALIAN NATURALIST. 27 
NATURE AND THE MECHANISTIC CONCEPTION 
OF LIFE. 
By G. P. Darnell-Smith, B.Se., F.1.C. 
(Abstract). 
Loeb regards the fundamental process, which is the 
elemental component of all psychic phenomena as the ac- 
tivity of the associative memory or of association, and by 
associative memory, he means the mechanism by which a 
stimulus brings about not only the effects which its na- 
ture and the specific structuye of the irritable organ call 
for, but by which it brings about also the effects of other 
stimuli, which formerly acted upon the organism almost or 
quite sumultaneously with the stimulus in question. If 
we accept this, and I take it here as a working ba- 
sis, we are then brought to the theory that only certain 
species of animals possess associative memory and have 
consciousness, and that it appears in them only after they 
have reached a certain stage in their ontogenetic develop- 
ment. 
Tt becomes evident that the unravelling of the me- 
chanism of associative memory is the great discovery to 
be made in the field of brain physiology and psychology. 
And now in this connection I wish to put prominently 
before you an idea—-an idea which I believe is original— 
that has, I think, an important bearing upon this subject 
and upon heredity itself. 
We have to remember that all life phenomena are ul- 
timately due to motions or changes occurring in colloidal 
substances. The question is which peculiarities of the eol- 
loidal substances can make the phenomena of associative 
memory possible. The answer to that question, I think, 
ig that the behaviour of any colloid depends upon its pre- 
vious history. 
In support of this contention, I may cite the three fol- 
lowing examples :— 
(a) If a gelatine solution, after being kept for a short 
time at 70-80 degrees, is cooled, say, to 25 de- 
erees, the value then observed for its osmotic 
pressure is considerably higher than it was be- 
fore the solution was heated. Only after the so- 
lution has been kept some days is there a return 
to its former value. The osmotic pressure ex- 
hibited by a gelatine solution is, therefore, to 
some extent dependent on its previous history. 
