D. J. DAVIS 655 



Streptococcus infections of the respiratory passages may arise from an endoge- 

 nous or an exogenous source. The endogenous source is chiefly the tonsil, adenoid, and 

 pharyngeal mucosa, as above stated, and no doubt gives rise to many of our secondary 

 and terminal infections. On the whole, streptococci from this source are not very 

 virulent or contagious, at least for normal persons, but may be highly fatal to those 

 whose resistance is lowered by disease. The exogenous streptococci are those coming 

 from outside sources through milk, contact, droplet infection, etc., and are usually 

 more virulent and may be responsible for epidemics. We should recognize the possi- 

 bility that the endogenous streptococci may become more virulent and aggressive and 

 thus initiate an outbreak by contact or otherwise. For example, in measles epidemics 

 in military camps, secondary streptococcus infections, at first not so virulent, may 

 later become highly so and ultimately give rise to primary streptococcus pneumonias 

 and empyemas without measles or another disease as a predisposing factor. 



FUSIFORM BACILLI AND SPIROCHETES 



The association of these two organisms in the body has been noted by many 

 observers both in normal and diseased states. Certain points remain obscure. Miss 

 Tunnicliff ' has offered striking evidence that the bacilli and spirochetes are phases of 

 a single organism, and Mellon^ has described various structures in the life-history of 

 these bacilli strongly pointing to wide variations and interesting mutational phenom- 

 ena. For our purpose, without attempting to establish the identity or non-identity 

 of these organisms, we shall assume their almost invariable association in certain local- 

 ities and processes. It is now being recognized that these organisms are of great im- 

 portance both in normal and diseased states, being found constantly in every mouth 

 and throat as opportunists. Under suitable conditions they tend to produce putrid 

 and gangrenous lesions. 



Of peculiar interest are their association and morphological relations to other bac- 

 teria in connection with two structures, namely, the tonsils and the teeth. Evidently 

 in these two localities they thrive abundantly and from here as centers are dissemi- 

 nated to other organs and tissues of the respiratory passages. In the tonsil crypts fre- 

 quently occur peculiar granular bodies.^ These are cheesy-like particles, foul smelling, 

 small, gray or yellow, single or more often multiple, lying in the crypts, never in the 

 tissues proper. In microscopic sections they are seen to be made up of filaments ar- 

 ranged in raylike fashion, suggesting actinomyces. These structures are remarkably 

 uniform. On analysis, they are seen to be composed chiefly of four kinds of organisms 

 evidently growing together in symbiosis, namely, leptothrix, fusiform bacilli, spiro- 

 chetes, and streptococci. The leptothrix grows under anaerobic conditions and in the 

 crypts develops into a cluster of filaments some of which radiate to the periphery, 

 forming central stalks about which fusiform bacilli are arranged perpendicularly, 

 closely resembling the structure of a test-tube brush. Scattered throughout this growth 

 are very large numbers of spirochetes and streptococci. The streptococci in these 

 masses are both hemolytic and non-hemolytic. The hemolytic are aerobic and quite 



'Tunnicliff, R.: ibid., 33, 147. 1923. 



^Mellon, R. R.: /. Bact., 12, 279, 1926. 



3 Davis, D. J., and Pilot, I.: J. A.M. A., 79, 944. 1922, 



