Later Additions up to the year 1892. 35 



tissue (as in the cases already alluded to at the com- 

 mencement of this chapter — viz. the leaf of Begonia, 

 portions of sea-anemones, jelly-fish, &c). For in 

 all these cases of repair, regeneration, and what may 

 be called somatic reproduction, we have only to suppose 

 that not all the idio-plasm-B of any given ontogenetic 

 stage is consumed in the formation of that stage, and 

 therefore that the residue is passed on to the later 

 stages in a latent condition. It will then be avail- 

 able at any time to re-develop tissue corresponding 

 to that particular stage, should that particular tissue 

 happen to be lost by accident or disease. For example, 

 if some of the idio-plasm-B of the very first onto- 

 genetic stage, or true germ-plasm, should thus be 

 passed on in an undifferentiated condition through 

 the somatic-tissues subsequently formed at later onto- 

 genetic stages, then we can understand why an entire 

 organism is reproduced from a fragment of these 

 tissues — or of those among which particles of such 

 residual and undifferentiated germ-plasm happen to 

 be scattered. Similarly, if idio-plasm-B of the onto- 

 genetic stage at which a limb is formed be not all 

 consumed in constructing the limb, then the limb, 

 if afterwards lost, will be re-constructed, although an 

 entire organism will not be reproduced from a frag- 

 ment of somatic-tissue. And similarly also with the 

 mere repair of injuries, where the only overplus of 

 idio-plasm-B is that of idio-plasm-B belonging to the 

 very last stages of ontogeny. 



But, it is almost needless to observe, this kind of 

 transmission of idio-plasm-B from one stage of on- 

 togeny in an unaltered condition to subsequent stages, 

 is not to be confused with the other kind of trans- 



D 2 



