ORGANIC , EVOLUTION EECONSIDERED. 139 



Strong evidence is furnished for the above views by the his- 

 tory of disease. Scar-tissue, for example, continues to repro- 

 duce itself as such ; like produces like, though in this instance 

 the like is in the first instance a departure from the normal. 

 Gout is well known to be a hereditary disease ; not only so, but 

 it arises in the offspring at about the same age as in the parent, 

 which is equivalent to saying that in the rhythmical life of 

 certain cells a period is reached when they display the behavior, 

 physiologically, of their parents. Yet gout is a disease that can 

 be traced to peculiar habits of living and may be eventually 

 escaped by radical changes in this respect — that is to say, the 

 behavior of the cells leading to gout can be induced and can be 

 altered ; gout is hereditary, yet eradicable. 



Just as gout maybe set up by the formation of certain modes 

 of action of the cells of the body, so may a mode of behavior, 

 in the nervous system, for example, become organized or fixed, 

 become a habit, and so be transmitted to offspring. It will pass 

 to the descendants or not according to the principles already 

 noticed. If so fixed in the individual in which it arises as to 

 predominate over more ancient methods of cell behavior, and 

 not neutralized by the strength of the normal physiological ac- 

 tion of the corresponding parts in the other parent, it will reap- 

 pear. We can never determine whether this is so or not before- 

 hand ; hence the fact that it is impossible, especially in the case 

 of man, whose vital processes are so modified by his psychic 

 life, to predict whether acquired variations shall become heredi- 

 tary ; hence also the irregularity which characterizes heredity 

 in such cases ; they may reappear in offspring or they may not. 

 In viewing heredity and modification it is impossible to get a 

 true insight into the matter without taking into the account 

 both the original natural tendencies of living matter and the 

 influence of environment. We only know of vital manifes- 

 tations in some environment ; and, so far as our experience 

 goes, life is impossible apart from the reaction of surround- 

 ings. With these general principles to guide us, we shall at- 

 tempt a brief examination of the leading theories of organic 

 evolution. 



First of all, Spencer seems to be correct in regarding evolu- 

 tion as universal, and organic evolution but one part of a 

 whole. No one who looks at the facts presented in every field 

 of nature can doubt that struggle (opposition, action and reac- 

 tion) is universal, and that in the organic world the fittest to a 



