514 BACTERIOLOGY. 



to obtain the immunizing substances in a more concen- 

 trated form. Foa and Scabia and F. and G. Klein - 

 perer prepared glycerin extracts, after the manner of 

 Koch, calling their extract " pneumoprotein." At 

 present, however, a protective serum is obtained from 

 horses by the repeated injections of fully virulent 

 pneumococci in exactly the same manner as in the pro- 

 duction of antistreptococcus serum. 



Therapeutic Experiments. Curative experiments in 

 man have also recently been made with the blood-serum 

 of immunized animals and of persons who have recov- 

 ered from an attack of pneumonia. The most success- 

 ful of these were conducted by F. and G. Klemperer. 

 These authors hold that in man during the pneumonic 

 process there is a constant absorption into the circula- 

 tion of this toxic albuminous substance produced by 

 the bacteria in the lungs. This continues until event- 

 ually the same antitoxic substance is produced in the 

 circulation that has been seen to occur experimentally. 

 It is then that the crisis occurs. The bacteria are 

 neither destroyed nor is their power to produce pneu- 

 motoxin lessened; but the third factor the antipneumo- 

 toxin now exists and neutralizes the toxic substances 

 as they are produced. They apparently demonstrated 

 that the serum of the blood of patients after the crisis 

 of pneumonia contained antitoxic substance, and was 

 capable, in a fair number of cases, of curing the dis- 

 ease when injected into infected animals. They have 

 made preliminary observations upon patients with a 

 view of inducing the crisis by the injection of the 

 blood-serum of persons convalescent from pneumonia, 

 and which, consequently, contain the antitoxic body. 

 In six pneumonic patients the results were promising. 



