444 THE PENN MONTUILY. [June, 
since animals of the lowest types possess powers of movement, 
their activity has necessarily been an immediate cause, while sur- 
rounding circumstances have exercised a controlling influence, 
Animal activity must be traced to the generation of force or 
motion by a protoplasmic body which is constantly supplied with 
nutriment. This production of force is the basis of the acts of ani- 
mals, up to and including man; often, as remarked by Prof. Bain, 
displaying itself in aimless discharges or playful movements, as in 
lambs and boys. 
But we observe even in very simple organisms, as the Amoeba, 
etc., that many movements are not aimless, nor without design. 
We observe that these mere specks of jelly devour nutritious sub- 
stances, and reject the innutritious, that they even distinguish 
between the Diatom which contains protoplasm within its shell, 
and the empty shell. Many facts of this kind lead us to believe 
in the consciousness of these pioneers of life, and seem to show 
that they have experiences of the pleasures of nutrition, and of 
the pains of retaining insoluble substances in the seats of assimi- 
lation. It would also appear that they remember these sensations, 
so as to seek the pleasures and reject the pains, when in the course 
of their wanderings they again come into contact with the ma- 
terial objects which have caused them. Given these two terms, 
sensibility (consciousness) and memory, and we have the con- 
ditions by means of which the entire complex superstructure of 
the affectional and the intelligent acts has been elaborated out of 
mere movements. 
This has been accomplished by the well-known laws of organi- 
zation of habits, and heredity. . The performance of an act under 
stimulus, so modifies the structure of the bioplasts of the brain, as 
to facilitate its repetition. With further repetition the organiza- 
tion is soon complete, and action follows the stimulus without 
direction, so long as no adverse influence affects the consciousness. 
Whether the act be one of the Rational or Anesthetic orders, from 
this habitual stage it becomes automatic in the true sense, between 
which and the reflex act no line can be drawn. It is evident that 
the degree of consciousness present in animals will depend on the 
number of changes appearing in their surroundings, whether due 
to modifications of the external world, or movements of their own 
bodies. Inasmuch as the habits of the lower animals are few and 
simple, most of them must be automatically performed, the con- 
