1908.] 



Diffusion into Living Cells. 



107 



of stain employed. The factors which hasten diffusion are heat, alkalies, and 

 time ; and those which delay it are acids and neutral salts. But the rate of 

 diffusion depends also on the concentration of the stain, for if this is weak 

 a large sum of factors to produce staining is required ; but if it is very 

 concentrated the cells may stain even in the presence of acid. Since all 

 these items are variables, I have constructed a formula by which, if some of 

 them are known quantities, the others can be readily determined. 



By this means the coefficient of diffusion of a cell can be obtained, and it 

 varies with the class of cell. 



I have also stated that the diffusion of substances other than stain may 

 appear similarly to depend not only on their concentration but on the 

 coefficient of diffusion of a cell. But other substances may be alkalies, acids, 

 or salts, and may affect the diffusion of neighbouring substances and be so 

 affected themselves. I have given a means by which this effect can be 

 determined and a unit made. Then, provided the unit of a given substance is 

 known, and provided the coefficient of diffusion of a given cell is known, the 

 comparative rate of effect of the given substance on the given cell can be 

 ascertained by referring to the equation.* 



In medicine, for instance, drugs and sera are frequently given with 

 a view to affecting certain cells, yet, as far as I know, no steps are taken 

 either to ascertain the rate of effect of the drug on the cells, or suitably to 

 modify the alkalinity of the blood by treatment, in order to produce 

 maximum results according to the temperature of the patient. The point 

 appears worthy of consideration. 



In the case of bacteria, it is frequently heard that certain bacteria are 

 more resistant to antiseptics and drugs than others. It is possible that this 

 varied resistance may be summed up in the expression " coefficient of 

 diffusion." If antiseptics could be rendered alkaline according to the 

 coefficient of the bacteria which they are intended to kill, and according to 

 the temperature, it might lead to a reduction of the concentration of the 

 antiseptic, with consequent saving of cost and increase of efficiency. 



Since the blood fluids affect bacteria, it seems desirable to know the 

 coefficient of diffusion of the bacteria when estimating the effects of the 

 fluids on the cells. Again, since erythrocytes will diffuse bodily into agar 

 jelly and remain suspended in it (2), and since droplets of liquid will diffuse 

 into the colloid cytoplasm of leucocytes and remain suspended in it (red 



* The knowledge that heat accelerates the diffusion of substances into cells has already 

 been applied in some researches by Dr. C. J. Macalister and myself in order to 

 demonstrate an excitant for leucocytes in the plasma of cancer patients (' Proc. Roy. Soc 

 Med.,' December, 1908). 



