HEREDITARY TRANSMISSION AND VARIATION. 85 



takes the form of its parent, having all the properties 

 and peculiarities of the original plant. 



Sometimes this process, which the gardener performs 

 artificially, takes place naturally ; that is to say, a little 

 bulb, or portion of the plant, detaches itself, drops ofi', 

 and becomes capable of growing as a separate thing. 

 That is the case with many bulbous plants, which throw 

 off in this way secondary bulbs, which are lodged in 

 the ground and become developed into plants. This 

 is an asexual process, and from it results the repetition 

 or reproduction of the form of the original being from 

 which the bulb proceeds. 



Among animals the same thing takes place. Among 

 the lower forms of animal life, the infusorial animalculse 

 we have already spoken of throw off certain portions, 

 or break themselves up in various directions, some- 

 times transversely or sometimes longitudinally ; or they 

 may give off buds, which detach themselves and 

 develop into their proper forms. There is the common 

 fresh-water Polype, for instance, which multiplies itself 

 in this way. Just in the same way as the gardener is 

 able to multiply and reproduce the peculiarities and 

 characters of particular plants by means of cuttings, 

 so can the physiological experimentalist, — as was shown 

 by the Abbe Trembley many years ago, — so can he do 

 the same thing with many of the lower forms of 

 animal life. M. de Trembley showed that you could 

 take a polype and cut it into two, or four, or many 

 pieces, mutilating it in all directions, and the pieces 

 would still grow up and reproduce completely the 

 original form of the animal. These are all cases of 



