578 BIOLOGY OF PNEUMOCOCCUS 



In intradermal infections in rabbits with Type I pneumococci, it 

 appears that similar mortality-rates may be expected. Barnes and 

 Clarke, in investigations* (1934) on the intradermal method, ob- 

 served extremely wide variations in the number of pneumococci 

 present in blood samples taken twenty-four hours after infection. 

 Because of the time at which serum treatment of rabbits is ordi- 

 narily begun in this method, it is impossible to base dosage on the 

 severity of septicemia, inasmuch as this condition cannot be read- 

 ily determined until twenty-four hours after taking blood samples. 

 As a result of this and other objections (irregularity in suscepti- 

 bility to infection, et cetera), 531 ' 533 the intradermal method of as- 

 saying antipneumococcic serum is impracticable for routine use. 



Tests for the curative effects of antipneumococcic serum in mice 

 have also been advocated. Coventry 286 reported that a majority of 

 mice could be saved by administering concentrated serum intra- 

 peritoneal^ four hours after an injection of Type I culture had 

 been given by the same route. Parish (1930) 1051 studied the thera- 

 peutic effect in mice of serum given intravenously at intervals of 

 one and one-half to seven hours after the intraperitoneal injection 

 of culture. It was found that serum was effective when given in this 

 manner but, as was to be expected, the longer the interval between 

 injections, the fewer the animals that survived. Petrie and Mor- 

 gan 1086 reported investigations on the curative action of antipneu- 

 mococcic serum in mice and stated that in the case of Type I re- 

 covery might take place even when a bacteriemia was present. The 

 serum was administered intravenously up to twelve hours after 

 inoculation. The outcome of the test was apparently conditioned 

 by the amount of antibody injected, the time of its injection in re- 

 lation to the infecting dose, and the degree of infection at the time 

 of serum administration. The authors thought that the test might 

 prove satisfactory as a means for standardizing therapeutic serum. 



In a later communication, Morgan and Petrie 917 observed that a 

 comparison of the curative and protective tests showed that both 



* Unpublished. 



