OTHER THEORIES OF SPECIES-FORMING. 221 



realises the incalculable number of these cells and despite the rich- 

 ness in variety of proteid substances, it will be impossible to con- 

 ceive that each kind of cell should have its own kind of proto- 

 plasm. There is here, apparently, an insurmountable difficulty, but 

 one which it is easy to do away with by a very simple concep- 

 tion. This conception consists in distributing the complex charac- 

 ters and properties, innumerable in living beings, into elementary 

 characters and properties much less numerous, which, by varying 

 combinations, produce the almost infinite variety that we observe 

 in the inorganic world. Just as with a score and a half of letters 

 one may form all of the words of the human language, so with the 

 elementary properties of which the actual number is still very con- 

 siderable, one may reproduce all the characters of living beings in 

 all their variety and complexity. It suffices, then, to admit that 

 these elementary characters and properties are represented by as 

 many material particles, and the problem is solved. These particles 

 are the pangenes. 



The pangenes, then, are small, organic particles, invisible to 

 the microscope, formed of an enormous number of chemical mole- 

 cules and differing from the most complex chemical substances 

 by three properties which are common to all of them and which 

 are characteristic of living matter; they nourish themselves, in- 

 crease in size, and multiply themselves by division. Beside these 

 three general properties which make living molecules of them, 

 the pangenes possess particular properties depending upon their 

 chemical constitution, differing for each of them, and which are 

 bound to them indissolubly in such a manner that, wherever a 

 pangene finds itself, the elementary property or character special to 

 it will show itself if internal and external conditions permit of this 

 manifestation. Latent or patent, potentially or evidently, the char- 

 acter is always there where is the corresponding pangene. Each 

 cell contains a great number of pangenes in activity, and its charac- 

 ters and properties in sum are the resultant of the elementary 

 characters and properties of the pangenes composing it: just as the 

 anatomical and physiological characters and properties of the living 

 individual are resultant of the anatomical and physiological charac- 

 ters of the cells composing it. 



It is necessary to conceive of the cellular protoplasm as formed 

 of innumerable pangenes bathed in a liquid in which are dissolved 

 substances purely chemical : albumen, glucose, salts, etc. Perhaps 

 similar substances penetrate the pangenes themselves, but we do 

 not know this. 



The nucleus contains in general all the kinds of pangenes that 

 compose the individual. But these pangenes are there in a sort 



