176 TEE POPULAR SCIENCE MONTHLY. 



flamed do not present unimpaired pathological evolution, but, on the 

 contrary, furnish still additional instances of physiological develop- 

 ment. It is chiefly, therefore, in cases of accidental sudden death 

 from violence that the designed type of development (both pathologi- 

 cal and physiological) can be studied best at all. But here, again, 

 specimens of pathological evolution would occur less often than those 

 that are physiological : first, because the whole number of pathologi- 

 cal cases is less than the physiological ones ; and, second, because 

 individuals undergoing pathological development are less exposed to 

 the liability of death by violence ; they, like young individuals under- 

 going physiological evolution, require more rest, warmth, and frequent 

 feeding, and are less strong and vigorous, than others whose physio- 

 logical development has been completed, and who are, therefore, more 

 disposed to cope with the risks and hardships of out-door life and 

 labor, under which circumstances death from violence more frequently 

 occurs. 



At any rate, it is nothing else than an axiomatic proposition that 

 similar organisms, impressed with similar stimuli, under similar cir- 

 cumstances, will lead to the development of similar structures. Now, 

 it is evidently only by the rarest possibility that we could meet, in the 

 civilized human subject, with a succession of instances in which all 

 these conditions had prevailed. In man and domesticated animals, it 

 is even observed that physiological growth difiers widely, but, within 

 certain limits, in diSei'ent individuals of the same age, species, etc. : it 

 is only in wild animals and plants that we observe uniformity of type ; 

 much less, tlien, need we expect to find this uniformity in evolutionary 

 processes that are pathological ; especially, too, when it is only sought 

 for in man and domestic animals. 



Finally, notwithstanding the difiSculties I have mentioned, enough 

 subservience to a fixed type on the part of pathological new forma- 

 tions has been observed, especially in cases where the new growth 

 and its cause have been limited and simple, to warrant the assertion 

 that pathological evolution in this respect is analogous with physio- 

 logical development. 



This analogy may be further established by considering various 

 other disturbing conditions (in addition to cold) which act disastrous- 

 ly alike in the two kinds of evolution ; but this may be reserved for a 

 subsequent paper, when we may also present a neio method of study, 

 based upon the views herein laid down, and by the pursuit of which 

 it is possible the nature, cause, and prevention of disease, may be in- 

 vestigated more after the manner oT the exact sciences. 



