43^ Eimer on Growth and Inheritance 



just as true to say that the germ cells are not an end in 

 themselves, but serve only to produce the soma.' In spite of 

 this obvious slip, Professor Eimer has good reason on his side 

 when he says that we have as much right to predicate 

 immortaUty of many of the multicellular animals as of those 

 which are unicellular. It often happens that sea-anemones 

 which have been well fed will spontaneously bisect them- 

 selves. This process will occur again and again, and seeing 

 that some of them can live at least sixty years without it, 

 it is quite impossible to deny immortality to them if, on 

 similar grounds, we attribute it to the lowest organisms. 



As an example of characters which have been develoj)ed 

 independently of any 'natural or sexual selection,' Eimer 

 adduces ^ the markings of certain garden snails. 



* The striping,' he observes, * might be regarded as an ornament 

 which acted as an advantage in sexual selection, but such an assump- 

 tion is inconsistent with the following facts. I have observed for 

 years in my garden that striped and unstriped individuals of Helix 

 hortensis unite without any selection; and what makes this case 

 particularly noteworthy as a support for my view of the compara- 

 tively slight effect of sexual crossing in the production of intermediate 

 forms (one-sided heredity) is this, that the offspring of these striped 

 and unstriped parents are again striped or unstriped — in spite of con- 

 stant crossing (panmixis) these two forms appear everywhere side by 

 side, with no connecting forms between them.' 



That some kind of internal force — though not ' a special 

 force of evolution' — regulates the efflorescence of new 

 characters is fully affirmed by Eimer, and this conclusion he 

 deems supported by phenomena to be observed in cater- 

 pillars, which have not only a tendency to repeat the same 

 markings in their successive segments, but to exhibit them 

 at an earlier and earlier age, although no advantage to them 

 appears thence to arise. He also cites ^ an earlier utterance 

 of Weismann himself in the same sense, and yet the position 

 1 P. 75. . . 2 p, 73, 



