Pneumococci in Experimental Lobar Pneumonia. 185 



113 (1045) 



The effect of previous intravenous injection of pneumococci upon 

 experimental lobar pneumonia produced by the method 

 of intrabronchial insufflation. 



By B. S. Kline and S. J. Meltzer. 



[From the Department of Physiology and Pharmacology of the 

 Rockefeller Institute for Medical Research.] 



We wish to report a result obtained in a series of experiments 

 in which the effect of intravenous injections of pneumococci upon 

 subsequent experimental pneumonia was studied. Forty-nine 

 dogs were used in these experiments. Observations were made 

 upon the extent and morphology of the pneumonic process, the 

 leukocytic reaction, the occurrence of agglutinins and the presence 

 of living organisms in the blood and in the lungs. In one series, 

 the animals were given intravenously each day for five days 0.7 

 c.c. of a broth culture of pneumococci per kilo of body weight. 

 In another series graduated doses were given, beginning with 

 0.07 c.c. per kilo of body weight and gradually increased to the 

 fifth and last injection of 0.7 c.c. per kilo. In both series on the 

 sixth day, the dogs were given an intrabronchial injection of 

 pneumococci. With groups of these animals, control dogs were 

 also injected intrabronchially with pneumococci. The animals 

 were killed at intervals from nineteen to forty-nine hours after the 

 intrabronchial injection. 



We wish to confine our present report to one significant result 

 namely: the rapid disappearance of the organisms from the 

 pneumonic lungs of the animals previously injected intravenously 

 with pneumococci. 



In previous experiments reported from this laboratory living 

 organisms were observed in the lungs of dogs with experimental 

 lobar pneumonia as late as the third day after the beginning of 

 the process. The results of the lung cultures in the present experi- 

 ments may be seen from the charts. 



It is evident from these charts that previous intravenous 

 injections of pneumococci bring about a destructive effect upon 



