162 THE NATURE AND ORIGIN OP LIFE 



In the liquid thus prepared let us consider a cell P. Be- 

 tween this cell and the medium physical and chemical 

 exchanges will go on just as before. But there will now 

 be something more the action of the diffused malic acid. 

 Now, along any straight line starting from the point O and 

 penetrating the cell-body at the two points a and b, it is plain 

 that the point a nearest to will receive a stronger value 

 of malic acid than the corresponding point b. The particu- 



(Lines Si, 82, 3, are arcs of circle with as centre.) 

 FIG. 9. 



lar effect of malic acid on the antherozoids will, therefore, be 

 stronger at a than at b ; and this will be true for all points a 

 in relation to corresponding points b along all the straight 

 lines starting from 0. 



Without pushing the geometrical analysis of the phenom- 

 enon any further, it will be understood that these differences 

 which are all in the same direction relatively to the point 

 form a component passing by that point 0. In fact, in 

 Pfeffer's experiment the antherozoids, while keeping up their 

 very capricious movements in the liquid, ended all of them 



