224 THE BEGINNINGS OF LIFE. 



Now by these experiments Onimus seems to have 

 shown quite conclusively that the corpuscles met with 

 in his experimental fluids had not been derived from 

 the fission of any visible pre-existing cells. It seems 

 almost equally certain that they did not even originate 

 from particles which were recognizable by the micro 

 scopic powers employed, since the fluids were at first, 

 to all appearance, perfectly homogeneous. Either, 

 therefore, the minute particles which were seen at a 

 later stage must have originated owing to some 

 primitive formative process taking place in a really 

 homogeneous organic solution, or else the fluid, seem- 

 ingly homogeneous, in reality contained the most 

 minute particles (microscopically invisible), derived in 

 some unknown way from the previously existing pro- 

 toplasmic elements of the tissues 1 . Further than this 

 we cannot go by direct observation reason alone must 

 be our guide in the selection of the one or the other 

 alternative. We, however, incline to the former view ; 



1 We are quite unable to disprove such a supposition. It is but the 

 germ theory under another form, and being based only upon analogical 

 evidence it belongs to the region of pure hypothesis. Those who would 

 be inclined to believe in the existence of such infinitesimal off-castings 

 from pre-existing cells are, however, no more able to prove that organic 

 units, seemingly originating de novo, are in reality derived from such 

 supposed invisible germs, than we are to disprove their hypothesis. We 

 must be guided therefore by evidence of an indirect nature, and those 

 who at present still doubt the probability of leucocytes originating de 

 novo, may, perhaps, be more inclined to admit that the tendency of the 

 evidence above adduced is strongly in favour of the actuality of such 

 a process, after they have read other portions of this work, relating to 

 the de novo origination of wholly independent living things. 



