142 SPONTANEOUS GENERATION. 



as manifested by unicellular and multicellular products. Unicellular pro- 

 ducts, however, there are ample grounds for maintaining, are susceptible 

 of differentiation to an almost unlimited extent, such differentiation being 

 essentially " molecular ." In the same manner that unicellular organisms 

 are now shown to correspond with the essential or primary elements 

 out of which all multicellular organisms are built up, so is it within the 

 region of possibility that entities yet exist which in a parallel manner find 

 their morphological equivalent in the constituent elements of unicellular 

 beings, and whose composition may be therefore correctly described as 

 simply molecular. Practically, such molecular organic entities exist in the 

 individually invisible or ultra-microscopic germs, discharged in a semifluid 

 state from the encystments of many monads. The embryonic condition of 

 one form typifying the adult state of one lower in the organic scale, is of 

 almost undeviating recurrence in the scheme of nature, and the conception, 

 therefore, of beings possessing in their highest state of development a corre- 

 sponding germinal, and yet ultra-microscopic or molecular condition, follows 

 as a natural and almost unavoidable deduction. It is, logically, within the 

 realms of the molecular alone, if anywhere, that the transition from the 

 inorganic to the organic is to be sought. Elsewhere, throughout the entire 

 range of cellular structures, the phenomena of reproduction are distinct and 

 uniform, rendering entirely untenable and nugatory their correlation with 

 the doctrine of abiogenesis. 



One final, though indirect, result of the rigid scrutiny to which the 

 monads, and other low unicellular organisms, have been submitted in order 

 to solve the mystery of their generation, remains to be recorded. As conclu- 

 sively proved by Professor Tyndall, Dallinger and Drysdale, Cohn, Kiihne, 

 and other investigators, such organisms in their germinal or sporular state 

 can successfully resist exposure to temperatures that prove fatal to any other 

 more highly organized structures, even up to and beyond the boiling-point 

 of water. So far, therefore, as they are brought in contact with the ordinary 

 conditions of the earth's surface they are practically i7idestructible. Nay 

 more ! as suggested by Professor Tyndall, there is no reasonable pretext for 

 assuming that there are not germs capable of resisting far higher tempera- 

 tures than those which have been hitherto subjected to experiment. Hence, 

 among all known organic forms, the Infusoria and their allies alone would 

 appear to possess the power of weathering the cataclysmic changes of the 

 universe, and, secure from all influences of heat and cold, of migrating 

 in safety through interplanetary space. 



