THE BEGINNINGS OF LIFE. 159 



in which a certain differentiation takes place, but that 

 there is no evidence whatever to show that the mole- 

 cular forces of this living matter (the c vital forces' of 

 most modern writers) are by this differentiation local- 

 ized in any one part more than in any other part 

 be it cell or be it intercellular tissue. c Neither is 

 there any evidence/ he says., c that any attraction or 

 other influence is exercised by the one over the other ; 

 the changes which each subsequently undergoes, though 

 they are in harmony, having no causal connection with 

 one another, but each proceeding, as it would seem, 

 in accordance with the general determining laws of 

 the organism.' Whilst believing that the penplast 

 corresponding with the cell-wall and intercellular tissue 

 of other writers is the seat of all the most important 

 metamorphic processes, out of which the various tissues 

 are produced, he also believes that this differentiation 

 is not brought about by any mysterious action on the 

 part of the cell or nucleus that it is rather a result 

 of intimate molecular changes taking place in the plastic 

 matter itself after a definitely successive, though in- 

 explicable fashion. The fundamental position of Pro- 

 fessor Huxley is, in fact, that the c primary differentia- 

 tion is not a necessary preliminary to further organi- 

 zation that the cells are not machines by which alone 

 further development can take place,' they are rather 

 mere indications of accustomed modes of evolution. 

 This view he has further illustrated as follows :- 

 c We have tried to show,' he says, c that they are not 



