360 BIOLOGY OF PNEUMOCOCCUS 



results are not significant. Cotoni and Truche tested some thirty- 

 one miscellaneous strains of pneumococci isolated from men, guinea 

 pigs, rabbits, and horses against thirty-eight samples of serum 

 from patients suffering from pneumococcal infections and against 

 immune serum from horses and sheep, as well as normal serum, 

 but the results of the agglutination reactions were confusing. For 

 example, normal horse serum, under the conditions of the experi- 

 ment, agglutinated the majority of the strains while normal sheep 

 serum affected only a few of them. The action of the immune 

 serums was indefinite, and Cotoni and Truche concluded that iden- 

 tification of pneumococci on the basis of agglutinability was un- 

 certain. 



The appearance of agglutinins in the blood during the course of 

 lobar pneumonia was studied by Chickering (1914), 222 who found 

 the antibody to be present in a large percentage of cases due to 

 Groups I, II, and IV. In the most severe cases and in fatal cases, 

 agglutinins could not be demonstrated nor could any be found, by 

 the technique employed, in the blood of patients suffering from in- 

 fection with Type III Pneumococcus. When agglutinins were de- 

 monstrable they usually appeared at the time of crisis, whereas in 

 some cases agglutinins were present for only one day, while in 

 others they persisted for several weeks. In infections due to pneu- 

 mococci of Types I and II the reaction was always specific for the 

 type of organism causing the infection, while in infections due to 

 organisms of Group IV the strain was agglutinated only by a se- 

 rum strictly homologous for that strain. 



In an investigation of the antigen-antibody balance in lobar 

 pneumonia, Blake (1918) 126 noted that prior to or coincident with 

 the appearance of agglutinins, pneumococci disappeared from the 

 blood. Patients who developed an excess of agglutinins over anti- 

 gen invariably recovered ; those who showed a progressive increase 

 in the excess of antigen without the development of demonstrable 

 antibodies invariably died. Clough 238 confirmed Chickering's find- 

 ings in demonstrating pneumococcal agglutinins in approximately 



