MENTAL AND SOCIAL EVOLUTION 127 



they become fainter and more fantastic, and at last 

 incoherent. This order is reversed, in the period of 

 waking, the last dreams, that precede the final open- 

 ing of the avenues of real sensations, coming from real 

 objects in the realm outside of the brain, being more 

 definite, and true to the reality, than those preceding. 

 In this sense, dreams are in line with other psychical 

 phenomena, having physiological marks. Profound 

 sleep may be prevented, by various abnormalities act- 

 ing on the senses, such as indigestible food in the 

 stomach, aromas coming in excess to the nostrils, or 

 unusual pressure on any part of the body. In such 

 cases, there is not profound sleep, and the molecular 

 nervous motions are more or less active, producing 

 corresponding representations of modified forms of 

 previous sensations and ideas, or dreams. 



REASON Is LIMITED. The higher the mentality, with 

 reference, of course, to the maintenance of a higher 

 adaptation of the organism to the material environ- 

 ment, the more readily will natural selection operate 

 in its perpetuation. Such a mentality is based upon 

 its emanation from and genetic connection with a ma- 

 terial environment. But, if that higher mentality is 

 what is termed merely a sentimental one, impractical, 

 artificial, and in correspondence only with a fantastic 

 and immaterial environment, it would be unfit for the 

 preservation of physical life, and therefore of its own 

 life. This condition arises from a diseased condition of 

 the nerve tissue. Man is so heterogeneous, especially 

 in his mental functions and social relations, that the 

 action of the principle is much less easy to trace. Yet, 

 the more the principle is studied, the stronger becomes 

 the evidence, that natural selection is operating just 

 as powerfully in man, and in all aggregations of men; 



