MEDICAL ADVANCEMENT AS PRECLUDING HUMAN EVOLUTION 229 



is an illustration of how natural selection operated in the development 

 of the expression of emotions in all present forms of animal life. It is 

 remarkable how uniform is the expression of the same emotion in all 

 the different animals and this illustration furnishes a rational explana- 

 tion. All life according to present views began in simple cell forms. 

 Those primordial forms of cells with reference to their responses to 

 stimuli might be conceived of as forming four possible classes. The 

 first group is formed by those cells that contract to all stimuli, whether 

 beneficial or harmful; the second by those cells dilating to all stimuli; 

 the third by those that contract to beneficial and dilate to harmful 

 stimuli; and the fourth by those that dilate to beneficial and contract 

 to harmful. Where consciousness exists the stimuli are referred to as 

 pleasurable and painful instead of beneficial and harmful. If there 

 ever did exist such a distribution of cells with reference to their 

 responses natural selection would immediately have been called into play 

 and the first three types eliminated. In the third type every response 

 is unfavorable to the welfare of the organism, because in relaxing to a 

 harmful stimulus the greatest amount possible of the life tissues must 

 be exposed to the harmful stimulus; whereas in contact with a bene- 

 ficial stimulus the least possible amount of the bodily tissues would be 

 benefited by contact and hence nutrition would be poor. In the fourth 

 type the responses are all the most favorable, because in dilating to a 

 beneficial stimulus nutrition is favored, and in contracting to a harm- 

 ful stimulus, thus bringing the least possible amount of the life tissues 

 in contact with the harmful stimulus, the organism is protected from 

 destruction. This is, consequently, the type to survive and to be the 

 perpetuator of life. The second type, providing it never gets in con- 

 tact with harmful stimuli, would be just as efficient as the fourth. But 

 it is inevitable for an organism in the course of its life to come into con- 

 tact with the harmful stimuli and this predetermines the fate of this 

 class. In the first type the nutrition is poor and elimination also is cer- 

 tain. There is a remarkable consistency throughout the whole realm of 

 organic life, with which each emotion manifests itself in connection with 

 the fourth type of responses. 



Natural selection has factored in the development of the expression 



