28 



I. INTRODUCTION TO VIRUSES 



added the same quantity of rennin, were expected to coagulate the 

 sooner, the lesser the concentration, but the result was entirely reverse ; 

 for example, of the two solutions of milk powder having different con- 

 centrations, /. e. 5 per cent and 0.15 per cent, the former coagulated 

 approximately 10 times as faster as did the latter if the rennin was not 

 added too much. ^ This phenomenon can be best explained by assuming 

 that the coagulation is a chain reaction, that is, the casein mole- 

 cules having been changed to some extent by rennin can affect other 

 intact molecules to accelerate the change, which should occur the more 

 readily the higher the concentration of casein. 



3. The Infection of Denaturation 



The inactivation change of phage particles by its antiserum appears 

 likewise to infect other intact particles to some extent as shown in 

 Table 3 (63). Namely, the same paradox phenomenon was observed as in 

 the case of rennin and milk, showing that the inactivation occurred the 

 more markedly the higher the concentration of phage particles. Thus, 



Table 3 

 Activity of Antiserum and of Tannin upon Phage 



when the concentration of phage particles is high enough to make the 

 particles come into contact with each other, the denaturation of a par- 

 ticle by the antiserum may successively be transmitted to other particles. 



