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 



