CAUSED BY A LOWERED COEFFICIENT 113 



There appears to be little doubt that archoplasm 

 does not exist normally in a living cell; it can be 

 produced in them, however, by lowering their co- 

 efficient of diffusion by keeping them for some hours 

 in extracts of dead tissues aYid this is, we believe, the 

 reason why it appears so frequently in living cancer- 

 cells. 



It is obvious that substances will, ceteris paribus, 

 diffuse more readily into a cell if it has a coefficient 

 of diffusion lower than its normal one, and, for the 

 same reason, vacuoles can more easily be induced in 

 it. For instance, no diffusion-vacuoles will appear in 

 fresh leucocytes when they are resting on a jelly which 

 will not cause the maximum diffusion of stain into 

 them; but if we lower their coefficient of diffusion, 

 and again place them on the same jelly, not only may 

 the maximum amount of stain now pass in, but it may 

 pass in to excess, and diffusion-vacuoles will appear. 

 This fact has led to the determination of a point of 

 scientific interest which has been controversial for more 

 than half a century. It has proved that the blood- 

 platelet is a living cell 1 ; for diffusion-vacuoles will 

 not appear in the normal blood-platelets, but if their 

 coefficient of diffusion is lowered by causing gradual 

 death, the lowering of the coefficient of diffusion so 

 occasioned will now permit "red spots" to be induced 

 in them. 



Our experiments up to the present have revealed 

 the fact that the coefficients of diffusion of all cells 

 fall gradually as their vitality fails, provided this loss 

 of vitality is gradual. The coefficient of diffusion of 



'A paper by myself on "V. Ph. Vacuolation of Blood-platelets " was 

 published in The Proceedings of the Royal Society, B., vol. Ixxxi, 1909. 



