The cytology of the exudate in the early stages of experimental pneumonia

Abstract

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 intrabronchial 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 exudate was predominantly mononuclear in character. These mononuclear 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 the blood or closely related forms. In pneumonia induced in animals heavily stained with lithium carmine, no cells stained with carmine took part in the formation of the exudate. No plasma cells were seen.