220 THE BEGINNINGS OF LIFE. 



of life, and that we must not transfer the seat of 

 real action to any point beyond the cell.' All these 

 instances of endogenous cell-formation which, indeed, 

 are frequently spoken of as examples of f free cell- 

 formation 3 do, in spite of their having taken place 

 in what are called c cells, 5 lead us on by insensible 

 gradations to those purest and most unquestionable 

 instances of free cell-formation, in which we may find 

 new living units, or plastides, arising in homogeneous 

 blastemata, and independently altogether of pre-exist- 

 ing cells. 



As we have already endeavoured to show, it would 

 be quite unreasonable to expect to get evidence of the 

 genesis of minute though fully formed Cells in blas- 

 temata. This was the old point of view and one 

 which was more justifiable in the days of Schleiden and 

 Schwann. Now, however, knowing as we do that a cell 

 with its cell -wall and nucleus is a product of evolution, 

 we must go back to formless matter, if we wish to 

 trace out the origin of the cell. We must look for 

 the appearance of mere specks minutest particles of 

 living matter which, continually growing in size, may 

 ultimately take on the form of cells, after the fashion 

 already described. 



We are thus led to enquire into the truth of a doctrine 

 long maintained by Charles Robin, though one which 

 has been as warmly repudiated by Virchow and his 

 school. The former believes that simple living units 

 are produced de novo in blastemata, and he maintains 



