INTERRELATIONSHIPS AMONG VIRUSES 153 



was found to produce inactivators against a number of viruses. Taka- 

 hashi (868) isolated from yeast a substance which was capable of rap- 

 idly inactivating the tobacco-mosaic virus. A chemical reaction between 

 the inactivating principle and the virus was therefore suggested. The 

 inactivator in this instance was destroyed by heating with i N NaOH 

 solution, but not by 2 A^ HCl. It was not a protein and gave on analysis 

 39-7 per cent C and 5.85 per cent H. The substance was said to be a 

 polysaccharide. Fulton (306) demonstrated that A. niger forms in the 

 medium a substance capable of inactivating a number of different plant 

 viruses J the effect of the inactivator was found to be exerted upon the 

 virus itself and not upon the plant. 



INTERRELATIONSHIPS AMONG VIRUSES 



Andrews (20) reported that the cultivation of influenza virus in a 

 simple tissue-culture rendered the culture unable to support the growth 

 of a biologically distinct strain of the virus added 24 hours later. The 

 tissue-culture, however, was still capable of supporting multiplication 

 of a related virus such as that of lymphogranuloma venereum. When 

 two strains of the influenza virus were added to the tissue-culture simul- 

 taneously, the one added in larger concentration suppressed the growth 

 of the other. 



Numerous reports have been made concerning the interference of one 

 virus by another, and even of inactivated bacteriophage with the active 

 agent of the same strain (1012, 1013). Henle and Henle (394) have 

 shown that even an inactivated virus, whether a homologous or a 

 heterologous strain, is capable of suppressing the development of the 

 influenza virus. 



Jungeblut and Sanders (467) suggested that poliomyelitis in ani- 

 mals may be aborted by the injection of another virus. A strong antago- 

 nism was observed between a murine virus mutant (virus passed 

 through mice for many generations) and the parent strain of the virus. 

 The murine virus was capable of counteracting large paralytic doses of 

 poliomyelitis j the two viruses virtually counterbalanced each other. 



Various other types of antagonism between viruses have been demon- 

 strated, as in the case of canine distemper or of lymphocytic chorio- 



