30 I. INTRODUCTION TO VIRUSES 



since the blood may be looked upon as a kind of free protoplasm or at 

 least as a physiological fluid similar to the protoplasm, there should 

 also exist in it a sort of the mechanism in favour of the infection. 



Lepeschkin (13) found that the granule coagulation of the protoplasm 

 of a spirogyra cell caused by a pressing of the cover glass spread 

 successively to another part of the protoplasm until the total mass 

 would be coagulated into minute particles. Such a coagulation was 

 found occasionally to be transmitted to another cell, never being con- 

 fined to the single cell. According to Biinning (70) a cutting of an 

 allium cell caused the coagulation of the protoplasm at the cutting site 

 and after the coagulation was spread throughout the whole protoplasm, 

 it was transmitted to the surrounding cells. The spreading velocity 

 was 0.09 to 0.13 mm. per min. according to him, and about 0.12 mm. in 

 spirogyra cell according to Lepeschkin. Thus in the protoplasm does 

 occur the infection of the coagulation or denaturation in such a striking 

 manner, and this must be one of the most important characteristics of 

 the protoplasm. Viruses may be unable to multiply without this cha- 

 racter of protoplasm. Presumably, not only viruses but also all the life 

 phenomena may depend upon this character, a concept which will be 

 considered in great detail in the next Part. 



