286 



LECTURES ON IMMUNITY 



A is the quantity of egg-albumen, B the quantity of pre- 

 cipitin, C that of antiprecipitin, D the rest of the fluid 

 given in quantity of physiological salt-solution. The total 

 quantity was always about sixty drops. 



ANTAGONISM BETWEEN PRECIPITIN AND ANTIPRECIPITIN 



The results may be calculated on the supposition that 

 the antiprecipitin is double as strong as the precipitin, i.e. 

 one drop of the antiprecipitin contains double the number 

 of equivalents as one drop of precipitin, and that the egg- 

 albumen is divided equally between the different equiva- 

 lents. Then the precipitate P formed may be calculated 

 from the formula : 



P = 



2C 



-A. 



I have therefore calculated this expression and tabulated it 

 under P. It will be seen that if P equals 0.6 or is greater, 

 precipitation is observed ; if it is less, not. 



The precipitate from egg-albumen is soluble in weak 

 solutions of acids or bases, but insoluble even in concen- 

 trated solution of sodium chloride. The acid solution 

 yields precipitation on neutralisation. On heating, it coag- 



