116 TEE DATA OF BIOLOGY. 



contained. But dare anyone assert this multiplication of 

 vital principles, duplicating not only all existing plants and 

 animals but all past ones, and amounting in the aggregate to 

 some millions? 



2. How are we to conceive that genesis of a vital principle 

 which must go along with the genesis of an organism ? Here 

 is a pollen-grain which, through the pistil, sends its nucleus 

 to unite with the nucleus of the ovule; or here are the 

 nuclei of spermatozoon and ovum, which, becoming fused, 

 initiate a new animal : in either case failure of union being 

 followed by decomposition of the proteid materials, while 

 union is followed by development. Whence comes that 

 vital principle which determines the organizing process? 

 Is it created afresh for every plant and animal? or, if not, 

 where and how did it pre-exist? Take a simpler form of 

 this problem. A protophyte or protozoon, having grown to 

 a certain size, undergoes a series of complex changes ending 

 in fission. In its undivided state it had a vital principle. 

 What of its divided state? The parts severally swim away, 

 each fully alive, each ready to grow and presently to sub- 

 divide, and so on and so on, until millions are soon formed. 

 That is to say, there is a multiplication of vital principles as 

 of the protozoa animated by them. A vital principle, then, 

 both divides and grows. But growth implies incorporation 

 of something. What does the vital principle incorporate? 

 Is it some other vital principle external to it, or some ma- 

 terials out of which more vital principle is formed? And 

 how, in either case, can the vital principle be conceived as 

 other than a material something, which in its growth and 

 multiplication behaves just as visible matter behaves ? 



3. Equally unanswerable is the question which arises in 

 presence of life that has become latent. Passing over the 

 alleged case of the mummy wheat, the validity of which is 

 denied, there is experimental proof that seeds may, under 

 conditions unfavourable to germination, retain for ten, twenty, 

 and some even for thirty years, the power to germinate when 



