276 EVOLUTION OF TO-DAY. 



from one individual to another, something like the 

 transference of fire, is his explanation. But this 

 is of little assistance. To call a principle heredity, 

 or memory, or a wave force, gives about the same 

 idea in any case ; and no one of them helps to un- 

 derstand why child is like parent. 



Dr. C. Jager has a very different view. He says 

 that all parts of the body are giving off from them- 

 selves an immaterial essence, which he calls soul 

 stuff. It is this soul stuff which gives to each ani- 

 mal its own specific odor, and it is different for every 

 individual. The reproductive products, he says, 

 collect this soul stuff, and store it up in themselves. 

 When now these reproductive bodies develop into 

 new animals, they take the form of the parents, since 

 they are filled with a like soul stuff. The essential 

 feature of this explanation is the supposition that 

 every part of the body is giving off from itself a 

 substance which is transferred to the next genera- 

 tion through the ovum and the spermatozoon. 



Darwin has also advanced an hypothesis, which he 

 calls pangenesis. He assumes that "the whole or- 

 ganization, in the sense of every separate atom or 

 unit, reproduces itself." Each part of the body is 

 constantly giving off from itself minute atoms, which 

 he calls gemmules. These gemmules circulate around 

 the body, so that there are present in every part 

 millions of them, some being present from every 

 other part of the body. When, therefore, the ovum 

 gives rise to a new individnal, it develops into the 

 parent, since it has within it gemmules from every 

 part of the body of the parent. Thus every peculi- 



