128 LIFE ON THE EAETH. 



regarding the origins, varieties, and perpetuations of 

 animal life on the earth. 



The science of life, in truth, is yet in its infancy. 

 Modern physiology has done much in expounding the 

 material changes by which individual life, springing 

 from its germ, whether through ova, fission, or budding, 

 is matured and maintained, and those further changes 

 by which it comes to an end. But the ultimate mys- 

 tery of generation is yet unresolved, and every specu- 

 lation hitherto vain as to that vital function by which 

 life is begotten from life, with resemblances and differ- 

 ences equally inexplicable under any known physical 

 laws. Putting the point in a simple but cogent form 

 What is that power, principle, or energy call it as 

 you choose which out of a single germ, or germs, or 

 germinal matter, or protoplasm (the names signify 

 little) invisible to the naked eye, can evolve, by gradual 

 accretion of fresh matter, the likeness of an anterior 

 being, even in its minute peculiarities of structure and 

 function which, in the human being, for instance, 

 can reproduce, after the omission of one, two, or more 

 generations, some marked feature of face, some organic 

 or functional disease, or even, as races as well as 

 families show, certain mental characters and endow- 

 ments F Or what, again, is that occult principle of life 

 in the seed which enables it, after the lapse of thirty 

 centuries, to germinate again into the perfect plant, 

 when the fitting conditions of light, heat, and atmo- 

 sphere are supplied? The molecular theory, which 

 serves to illustrate so many physical problems, is of no 

 avail here, nor does science through any other path 

 approach the solution of the mystery. 



