Orr 251 
Orr 
Orr takes as his starting point the conception that he 
has formed concerning the way in which the pluricellular 
organisms arise from the unicellular. 
It is easy to understand that after the unicellular 
organism in the course of generations had attained a 
certain size, its external surface might have become 
transformed in consequence of contact stimuli into a 
denser protective layer, and thereby have lost its repro- 
ductive capacity, which would have been preserved only 
in the inner part of the organism. 
“When such an organism as this would be divided 
into a number of pieces by the natural process of repro- 
duction those parts of the protoplasm which had not 
undergone a grosser material differentiation would be 
like the protoplasmic germs of all its ancestors, capable 
of responding to the same stimuli, and therefore of devel- 
oping in the same manner. The only difference between 
these and the ancestral germs would be the increased 
complexity of their nervous co-ordinations. But, on the 
other hand, part of the organism which has been dif- 
ferentiated into the denser outer layer would be in 
structure so different from the germs of the species that 
it would be incapable of responding to any of their accus- 
tomed stimuli and therefore incapable of repeating the 
development.” 
“But at every step in the evolution a part of the 
protoplasm retains its original qualities, only changing 
its nervous condition to a condition of greater complexity 
of co-ordinations. In this way the original protoplasm 
gradually adds to itself the co-ordinations for developing 
