NEUTRALISATION OF H^MOLYSINS 187 



is somewhat smaller than the calculated action. This ac- 

 cords with the observations on tetanolysin. The experi- 

 mental method was quite the same in the two cases. 



In a lecture held before the British Medical Association 

 at Oxford in July, IQO4, 1 Madsen has given curves repre- 

 senting the toxicity of vibrio, staphylo and streptolysin on 

 the addition of increasing quantities of their specific anti- 

 toxins. These curves indicate clearly the fact that the 

 Ehrlich phenomenon is quite apparent in all of them, 

 inasmuch as the right branch tends to bend asymptoti- 

 cally to the abscissa. 



In all experiments with the lysins the temperature, 

 which corresponds to the equilibrium, is that at which the 

 mixed fluids, toxin and antitoxin, are held during I h. to 

 2 h. before the blood cells are added. In this moment the 

 volume increases to so high a degree that the velocity of 

 reaction may be regarded as practically suspended. 



Cholesterin displays a neutralising influence upon teta- 

 nolysin, as is seen from the following table, indicating the 

 attenuation of 5 c.c. of a broth of tetanus bacilli on the ad- 

 dition of n c.c. of a io~ 6 normal solution of cholesterin and 

 so much salt-solution that the total volume was icc.c., 

 which reacted upon each other during 3 hours at 37 C. 

 After this time parts of this mixture were added to 8 c.c. 

 of horse blood suspension (2 per cent), and the action ob- 

 served. The equation of equilibrium indicates that I mole- 

 cule of reaction-products results from i molecule of lysin, 

 and i molecule of cholesterin. Of the cholesterin-solution 

 1.43 c.c. were equivalent to 5 c.c. of the broth, which there- 

 fore had the concentration 2.86 io~ 7 normal. 



1 Madsen: British Medical Journal^ Sept. 10, 1904, p. 12. 



