SCIENTIFIC PROCEEDINGS 



Abstracts of Communications. 

 Seventy-fourth meeting. 



Presbyterian Hospital, March i$, igi6. 

 President Loeb in the chair. 

 55 (i"9) 



The cytology of the exudate in the early stages of experimental 



pneumonia. 



By Frank A. Evans (by invitation.). 



[From the Department of Pathology of the Presbyterian Hospital.] 



The cells have been studied in the early exudate of pneumonia 

 produced in rabbits by intrabronchial injection of pneumococcus 

 group I, group IV, and by an attenuated strain of pneumococcus 

 furnished by Dr. Carrol G. Bull's laboratory at Rockefeller 

 Institute; by streptococcus hemolyticus and by a streptococcus 

 isolated from the mouth of a normal individual by Miss Olmstead 

 of Presbyterian Hospital ; and in the exudate in reaction to intra- 

 bronchial injection of 33 per cent, egg yolk in neutral broth. The 

 early exudate in three cases of human pneumococcus pneumonia 

 has also been available for study. 



In all of these lesions, although many polymorphonuclears 

 were often present, in many of the alveoli the cytology of the exu- 

 date was predominantly mononuclear in character. These mono- 

 nuclear cells may be classified as follows: a few typical small 

 lymphocytes of the blood ; a few epithelial cells from the alveolar 

 walls; relatively many oxydase-containing large mononuclears 

 greatly resembling the so-called transitional cells of the blood; 

 and almost as many non-oxydase containing large mononuclears of 



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