HEREDITARY TRANSMISSION AND VARIATION. 87 



this mode of multiplying by moans of cuttings is the 

 only secure mode of propagating very many varieties of 

 plants ; the peculiarity of the primitive stock seems to 

 be better preserved if you propagate it by means of a 

 slip than if you resort to the sexual mode. 



Again, in experiments upon the lower animals, such 

 as the polype, to which I have referred, it is most 

 extraordinary that, although cut up into various pieces, 

 each particular piece will grow up into the form of the 

 primitive stock ; the head, if separated, will reproduce 

 the body and the tail ; and if you cut off the tail, you 

 will find that that will reproduce the body and all the 

 rest of the members, without in any way deviating 

 from the plan of the organism from which these por- 

 tions have been detached. And so far does this go, 

 that some experimentalists have carefully examined 

 the lower orders of animals, — among them the Abbe 

 Spallanzani, who made a number of experiments upon 

 snails and salamanders, — and have found that they 

 might mutilate them to an incredible extent : that 

 you might cut off the jaw or the greater part of 

 the head, or the leg or the tail, and repeat the ex- 

 periment several times, perhaps, cutting off the same 

 member again and again ; and yet each of those 

 types would be reproduced according to the primitive 

 type : nature making no mistake, never putting on a 

 fresh kind of leg, or head, or tail, but always tending 

 to repeat and to return to the primitive type. 



It is the same in sexual reproduction : it is a matter 

 of perfectly common experience, that the tendency on 

 the part of the offspring always is, speaking broadly, 



