42 



EVOLUTION AND ANIMAL LIFE 



no recorded instance and men have searched diligently for 

 examples of spontaneous generation. No protoplasm has 

 been seen, or otherwise proved, to come into existence except 

 through the agency of already existing protoplasm. All life 

 comes from life. All those former beliefs of spontaneous 

 appearance of bees from the carcasses of oxen, flies from 



decaying flesh, hair worms 

 from horse tail hairs in 

 water troughs, and bacteria 

 and infusoria in infusions 

 of beef or hay have been 

 shown on scientific investi- 

 gation to be utterly with- 

 out basis of fact. 



But if protoplasm and 

 life do not appear, are not 

 being generated spontane- 

 ously in this earth epoch, 

 may they not have been 

 in earlier ages? Geologists 

 and biologists attempt to 

 explain most of the things 

 that happened in earlier 

 geologic ages by what they 

 observe to be happening 

 now. They would answer, 

 on this basis, that what 

 evidence we now have 

 should lead us to believe 



that the generation of life has never occurred. But there must 

 have been a beginning. Life has not always been. The ac- 

 cepted geological theory of the making of our earth precludes 

 the existence of life on it until the globe was cool enough for 

 organisms to exist. We know that there is a maximum of 

 temperature beyond which protoplasm inevitably coagulates. 

 When and where was this beginning of life? The biologist can- 

 not admit spontaneous generation in the face of the scientific 

 evidence he has. On the other hand he has difficulty in under- 

 standing how life could have originated in any other way than 

 through some sort of transformation from inorganic matter. 

 As a matter of curiosity we may glance at a few of the 





FIG. 32. Ascidian or sea squirt. 



