REACTIONS BETWEEN ANTIBODIES 23 



hours) and then found to behave like a solution of ricin. In 

 this case the process goes on so slowly that the ricin and 

 antiricin will have had sufficient time to combine before 

 their destruction has reached a noticeable degree. 



It is possible to separate partially the two neutralised sub- 

 stances by much less vigorous means ; namely, by shaking 

 their solutions with other solvents. Thus, for instance, Mad- 

 sen and Noguchi treated an innocuous mixture of saponin 

 and cholesterin, which unite so rapidly that their velocity 

 of reaction can scarcely be measured, in the following 

 manner. The mixture was evaporated to dryness and 

 thereafter ground to a powder, which was extracted with 

 chloroform or ethyl ether. These fluids possess a great 

 dissolving power for cholesterin. The residue of the 

 powder was dissolved in 0.9 per cent solution of sodium 

 chloride. The solution so prepared displayed the prop- 

 erties of a solution of saponin, especially in regard to its 

 haemolytic activity. 1 



Another experiment of the same nature was carried on 

 by Madsen and Walbum. 2 They prepared a mixture of 

 ricin and antiricin, which, after having been exposed for 

 two hours to 37 C., showed no toxic effect when injected 

 into guinea-pigs. This mixture was shaken for a time at 

 37 C. with an equal quantity of a 10 per cent suspension of 

 erythrocytes from a rabbit in physiological salt solution, 

 and then centrif ugated. The liquid was then shown to con- 

 tain an excess of antiricin by its attenuation of the aggluti- 



1 Madsen and Noguchi : Oversigt Ac. of Sc. of Copenhagen, No. 6, p. 461 

 (1904). 



' 2 Madsen and Walbum : " De la ricine et de 1'antitoxin," Centralblatt f. 

 Bakteriologie, 36. 253 (1904). 



