358 BIOLOGY OF PNEUMOCOCCUS 



appeared ten days after crisis. Similar results were obtained by 

 Rosenow (1903), 1158 who found that when culture and serum came 

 from the same patient agglutination was most pronounced, but in 

 none of the serums from sixty-five cases of pneumonia when tested 

 against twenty-five strains of Pneumococcus did agglutination fail 

 to take place. Jehle (1903) 678 was able to demonstrate relatively 

 high agglutinating power in the serum of all cases tested of croup- 

 ous pneumonia terminating in crisis but, contrary to Huber and 

 Rosenow, Jehle observed that only comparatively small amounts 

 of agglutinin were demonstrable forty-eight hours after crisis and 

 that the antibody had practically disappeared four days later. 



In a second communication, Rosenow (1904) 1159 reported addi- 

 tional tests on the serum of pneumonia patients which confirmed 

 his earlier results, and made the observation that pneumococci re- 

 planted from the agglutinated mass in immune serum were viable 

 as long as thirty days after being agglutinated. Wadsworth 1455 

 substituted for the whole culture as antigen saline suspensions of 

 pneumococci sedimented from twenty-four to thirty-six-hour-old 

 broth cultures and carried out agglutination experiments with im- 

 mune serum obtained from rabbits which had previously been in- 

 jected with dead and later with living pneumococci. With serum 

 from pneumonia patients in dilutions of 1 to 10 to 1 to 20 the anti- 

 gen gave positive reactions in five or six hours. Wadsworth con- 

 firmed Neufeld's negative results for normal rabbit and bullock se- 

 rum, but found that normal human serum in a dilution of 1 to 10 

 agglutinated pneumococci in less than eighteen hours. When the 

 serum was diluted in a proportion of 1 to 30, no agglutination 

 took place. In 1905, Longcope 824 described the sediment occurring 

 when pneumococci were added to serum obtained from pneumonia 

 patients, and also the accompanying swelling of the bacterial cap- 

 sule, previously observed by Neufeld. 



In a study of the various characters of a large number of strains 

 of pneumococci from a variety of human sources, Kindborg 

 (1905) 713 obtained immune rabbit and sheep serum of high agglu- 



