Intra-Bronchial Insufflation of B. megatherium. 25 



infiltration. In the cases of broncho-pneumonia produced by 

 the streptococcus or by the influenza bacillus there was no mor- 

 tality; at no time was there a bacteremia; the exudate contained 

 very little fibrin, but the framework of the lungs was invariably 

 and often very intensely infiltrated with leucocytes. 



In a third series of experiments, which has not yet been 

 published, we studied the effects of insufflation of a non-virulent 

 pneumococcus. This organism also caused the development of a 

 lesion which macroscopically resembled the lesion of lobar pneu- 

 monia produced by the virulent pneumococcus. However, there 

 was no mortality, no bacteremia, and an exudate comparatively 

 poor in fibrin; the framework of the lung was here again practically 

 free from leucocytic invasion. 



The results obtained with the non-virulent pneumococcus led 

 us to a study of the intra-bronchial insufflation of such a non- 

 pathogenic organism as the B. megatherium. Ten experiments 

 were made. The insufflation brought on a definite pneumonic 

 lesion in every case. From the gross appearance the lesion has 

 to be considered as that of lobar pneumonia of a milder type. 

 The entire process is essentially similar to the one caused by the 

 non-virulent pneumococcus, but its course is even milder. The 

 development is slower, the reaction is less intense and the resolu- 

 tion occurs sooner; there is practically no fibrin at all in the 

 exudate and bacteria can only occasionally be cultivated from 

 the exudate of 24 hours' duration. There is little involvement 

 of the framework. 



We show you here several lungs in the various stages of the 

 inflammatory process; the lesions were produced by the intra- 

 bronchial insufflation of twenty cubic centimeters of an eighteen 

 hour old bouillon culture of the B. megatherium. 



