The characteristic appearances exhibited by the surface colonies of both S and R pneumococci in 24 and 48 hour cultures upon rabbit blood agar have been reviewed. Emphasis has been laid upon the behavior and structure of the colonies formed by R pneumococci, their frequent similarity to the colonies formed by certain strains of Streptococcus viridans, and their failure to undergo rapid autolysis in the first 48–96 hours, a phenomenon which is highly characteristic of the S pneumococcus colonies. With the S pneumococci it has been shown that "pseudo rough" colonies may be immediately produced under certain unfavorable cultural conditions but such changes in colony morphology as these do not indicate that complete dissociation has taken place and that the organisms may be classified as true R pneumococci.
Article| November 01 1927
A COMPARATIVE STUDY OF SMOOTH AND ROUGH PNEUMOCOCCUS COLONIES
John R. Paul
From the Ayer Clinical Laboratory, Pennsylvania Hospital, Philadelphia.
Received: July 06 1927
Online ISSN: 1540-9538
Print ISSN: 0022-1007
Copyright, 1927, by The Rockefeller Institute for Medical Research New York
John R. Paul; A COMPARATIVE STUDY OF SMOOTH AND ROUGH PNEUMOCOCCUS COLONIES . J Exp Med 1 November 1927; 46 (5): 793–805. doi: https://doi.org/10.1084/jem.46.5.793
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