IMMUNITY IN EXPERIMENTAL INFECTIONS 139 



treatment upon rabbits carried out by Altemeier and Jones showed 

 that preoperative hif?h voltao:e roentgen irradiation was of value in 

 developing immunity against experimental peritonitis. They offer 

 no theory of the mechanism involved. 



Defense Against Viruses. — Tn regard to the defensive mech- 

 anism against viruses, the prevailing opinion as expressed by 

 Rivers (1928) and Ayeock (1931) seems to be that it is both 

 cellular and virucidal or humoral in nature nnd that the inflam- 

 matory response is secondaiy to cell injury. This is apparently 

 borne out by the experimental work of Andrews (1930). Some 

 of his conclusions are summarized as follows: (1) The virus of 

 lierpes can be cultivated successfully in tissue cultures (rabbit 

 testes) if dilute rabbit serum is employed. (2) Neither growth 

 of the virus nor the formation of inclusion bodies is obtained in 

 tissue cultures if immune serum is added to tlie culture before the 

 virus or together with it. (3) The virus of herpes will grow and 

 form inclusion bodies in tissue cultures Avhen immune rabbit testes 

 and normal serum are used. (4) Normal tissue is infected by the 

 virus witliin one-half ]iour at 17.5° C. or 37° C. if immune serum 

 is not present ; the later addition of immune serum does not pre- 

 vent growth of tlie virus nor the formation of inclusions. 



-Jamuni and Holden (1934) present evidence wliich indicates 

 that l)oth leucocytes and immune serum play a role in 'immunity 

 against herpes virus. The mononuclear cells are apparent!}" more 

 efficacious than polymorphonuclear cells in disposing of herpes 

 virus. They suggest that the virus is opsonized and then phago- 

 cytized although they were unable to verify this point. Their 

 j'esults indicate that phagocytic cells (immune or normal) bring 

 about a greater virucidal effect than can be obtained with immune 

 serum alone. 



Tolerance. — In addition to the various factors of defense dis- 

 cussed in this chapter the phenomenon of ''tolerance" perhaps 

 should be mentioned. Gunn (1923) regards this as very impor- 

 tant especially as regards certain toxemic disea cs. He cites the 

 specific congenital tolerance of the toad, rat and grass snake to 

 toad poison which has a digitalis-like toxic action and is a glu- 

 coside. He says that these same aninuils show a high degree of 

 tolerance to members of the same group of glucosides. The re- 

 sistance is due to an insusceptibility of tissue, especially that of 



