220 THE LAW OF JOHANNSEN. 



After all, characters in Metazoa are never transmitted, only 

 genes and combinations of genes are, and it is not more, nor 

 less wrong, to speak of the inheritance of acquired characters, 

 than it is to speak of the inheritance of innate characters. 



Now, whereas there is no direct transmission of characters 

 in more complex metazoa, there certainly is in all uni-cellular 

 organisms. 



If we notice a peculiar spine-like excrescence in Paramoecium 

 such as observed by Jennings, we may note how it gradually 

 diminishes in size and eventually disappears, and think nothing 

 further of it. And even if we see, that during this process of 

 disappearence of the spine at one end of the organism, the 

 other end of the animal is four times lost and regenerated, we 

 may not see any important connection between these two sets 

 of facts. It is more or less a matter of temperament. We may 

 now look upon this end which carries the excrescence as upon 

 its own daughter, for the whole animal divided into two and 

 we call the halves daughters of the individual, which we had 

 in our hanging drop before. And therefore, the end with the 

 spine is not only the same individual from the time at which 

 we began to observe it, until the moment at which the spine 

 was lost, but also the great-great-grand-daughter of the origin- 

 al animal, and therefore of itself, and if we so please, we cert- 

 ainly can say that this character, the spine, is inherited through 

 four generations. 



Only, we must be very clear, that this inheritance of this 

 spine is a different thing from the inheritance of a tail through 

 four generations of chickens. For the egg has no tail, and this 

 organ is made anew by the young individual at the stage of 

 development at which its mother grew a tail. The tail did not 

 merely persist like the excrescence on the Paramoecium, or the 

 virulence of the bacteria, or the Sudan III in the moths. Its 

 development is a function of the constitution of the generations 

 of cells which link the daughter to the mother, in the sense 

 that the presence of a tail in both, as compared to the possible 

 absence in other chickens, is more certainly caused by a like 



