KINETIC JELLY 141 



one digit from the coefficient of diffusion, and making 

 the jelly accordingly. Hence the equation given above 

 in reality is correct, for the coefficient of diffusion of 

 leucocytes is 12, and subtracting one digit from it makes 

 11, as given in the equation. With the jelly arranged 

 for 11, the nuclei are not yet stained, and death will not 

 occur for another unit of time. On the other hand, the 

 diffusion has already been sufficient for the atropine to 

 excite the cells, and when the given fifteen minutes of 

 time has elapsed, the cells will be seen, not dead, but 

 in the height of their excitation. 



Thus the rule is that, having ascertained the co- 

 efficient of diffusion of a cell, if we wish that cell 

 to be alive at the expiry of the given time, subtract 

 one digit from its coefficient of diffusion, and make 

 the jelly accordingly. 



This rule is an important one in this work, for 

 we shall, of course, frequently have to observe cells 

 in the act of excitation, which is an easy matter if 

 their coefficient of diffusion is known, as it only 

 remains to subtract one unit from any of the factors 

 which increase diffusion, and we get the right result. 1 



All forms of the polynuclear leucocyte respond 

 to atropine by exhibiting excitation of amoeboid 

 movements. In making them respond, however, the 

 different coefficients of diffusion of each class - of cell 

 must be duly regarded. The eosinophile cell has a 

 coefficient lower by one unit than the neutrophile; 

 and if it is required to excite it especially, the jelly- 



1 It will doubtless be realised that subtracting one unit of a factor which 

 increases diffusion, is similar in effect to subtracting one digit from the cf. 



