1885. ] Comparative Physiology and Psychology. 3 
as might be expected, movements cease, owing to combinations 
being satisfied for the time. Then too the simple nature of pro- 
toplasm has been by no means proven. It is being regarded as 
not only complex through atomic union, but as holding in its 
molecular construction secrets which the chemist may some day 
find operative in the inorganic affinities. There may be, as has 
been surmised, many kinds of protoplasm, and the ultimate basic 
substance may be beyond. The ova of the different animals seem 
to be protoplasm plus other things, differing from each other in 
quantities and composition. We know that certain animals add 
to their bodies chemical substances which form tissues, and that 
other animals do not, showing a variability of selective affinity. 
The psychologist who attempts to explain consciousness on the 
basis of molecular reaction is no more at a loss than the chemist 
who accepts such words as catalysis and isomerism as represent- 
ing acts of the atoms. 
Starting out, then, with the fair understanding that the Amceba 
moves by virtue of the operation of physical causes, and that 
speculations upon the origin of matter and force are foreign to 
the subject, we will see to what the assumption, if you choose to 
call it one, will lead. 
I invite earnest attention to the proposition I make here as a 
corollary from the apparent volition of the Amceba being molec- 
ular attraction. 
Locomotion and prehension of the Amæba are due mainly to ex- 
trinsic forces operating immediately upon its organism, whereas 
these phenomena in man and the majority of the intermediate meta- 
zoa are due immediately to intrinsic forces, as a rule, preponderating 
over the extrinsic, but nevertheless the extrinsic remain the remote 
causes of motion in all animals, 
In this there is a view of the evolution of volition from the so- 
called involuntary, its growth from the chemical affinities. 
The belief is current among biologists that if we reverse the 
conditions under which all life exists, all life would perish; if 
the reversal were slowly effected most would perish and but few 
survive ; if inappreciably slowly, it is highly probable that the 
number of surviving forms would be very large. The survival of 
any animal is evidence of its consonance with its surroundings, 
and the environment not only modifies and acts upon the animal 
to develop or destroy it, but also, from our chemical standpoint, 
