BIOLOGICAL INVESTIGATIONS. 151 



the fundamental importance of this science is not suspected by 

 most investigators. Nevertheless, it has been placed in its 

 proper relations by a number of writers, beginning, perhaps, in 

 definite modern form with Ewald Hering's paper, entitled, 

 " On Memory as a General Function of Organized Matter," 

 an address given before the Imperial Academy of Science at 

 Vienna in 1870. Ribot took substantially the same ground 

 in his work on "Heredity," in 1876, and Haeckel also in "Die 

 Perigenesis der Plastidule," 1876, both being ignorant of Her- 

 ing's previous publication and of each other's results. These 

 were followed by an equally independent restatement by Cope 

 in the American Nattiralist in 1889, and the lecturer came near 

 making a fourth in this list. Speculations upon the supposed 

 mysterious and indefinable nature of heredity might have had 

 a far more objective basis for the past twenty-nine years had 

 naturalists, whether in opposition or in approval, considered 

 Hering's theory worthy of their attention. 



Confusion exists in the minds of many naturalists, arising 

 from the ordinary conception of memory as a function of con- 

 scious intellectual effort and as something essentially distinct 

 from automatic action and habits of all kinds. No essential 

 distinctions actually exist, however, since the two grade into 

 each other. 



The essential common characteristic of both is repetition ; 

 and to represent this and avoid the risk of employing an old 

 word whose application had to be greatly extended, I have in 

 previous publications used the term "mnemism," or"mnemo- 

 nism," to express the nature of heredity, and "mnemogenesis " 

 for the theory. Before proceeding further in the argument of 

 this question it is necessary to glance hastily at the supposed 

 modes of transmission of characters. 



These can be divided into two classes : (i) those theories 

 that depend upon some peculiar substance supposed to have 

 always been distinct from the surrounding forms of protoplasm. 

 These necessarily assume some sort of corpuscles or organic 

 molecules to be the vehicles of transmission. (2) Those theo- 

 ries that regard the germ plasm as not transmitted from body 

 to body but as arising out of the ordinary protoplasm of the 



