III.] LIFE AND DEATH. 121 



duction, and is a consequence of the latter in both Protozoa and 

 Metazoa. Reproduction has, in his opinion, a directly 'fatal 

 effect,' and the reproducing individual must die. Thus the 

 may-fly and the butterfly die directly after laying their eggs, 

 and the male bee dies immediately after pairing ; the Or- 

 thonectides expire after expelling their germ-cells, while 

 MagospJmera resolves itself into germ-cells, and nothing 

 persists except these elements. It is but a step from this 

 latter organism to the unicellular animals which transform 

 themselves as a whole into germ-cells ; but in order to achieve 

 this they must undergo the process of rejuvenescence, which 

 Gotte assumes to be the same as death. 



These views contain many fallacies quite apart from the 

 soundness or unsoundness of their foundation. The process of 

 encystment, as Gotte thinks, represents, in the Monoplastides, 

 true reproduction to which multiplication by means of division 

 has been secondarily added. This encystment cannot be 

 dispensed with, for internal causes determine that it must 

 occasionally interrupt the process of multiplication by simple 

 division. But, on the other hand, Gotte also considers the 

 division of the contents of the cyst to be a secondary process. 

 The essential characteristic of encystment is a simple process 

 of rejuvenescence without multiplication. Hence we are forced 

 to accept a primitive condition in which simple division as well 

 as the division of the encysted individual were absent, and in 

 which reproduction consisted only in an often-repeated process 

 of rejuvenescence among existing individuals, without any 

 increase in their number. Such a condition is inconceivable 

 because it would involve a rapid disappearance of the species, 

 and the whole consideration clearly shows us that division 

 of un-encysted individuals must have existed from the first, and 

 that this, and not a vague and mysterious rejuvenescence, has 

 always been the real and primitive reproduction of the Mono- 

 plastides. The fact that encystment does not always lead to 

 the division of the contents of the cyst proves, in my opinion, 

 that not reproduction but preservation against injury from 

 without, was the primitive meaning of encystment. It is pos- 

 sible that at the present time there are but few Monoplastides 

 which are able to go through an infinite number of divisions 

 without the interposition of the resting condition implied by 



