212 THE INFECTIOUS DISEASES. 



Characters of the Organism. 



This organism is from 1.5 to 2 n long, sometimes grows in short chains, is motile, 

 and decolorizes by Gram's method. It grows readily on artificial media, usually devel- 

 oping a greenish pigment. It liquefies gelatin. Subcutaneous injection of cultures in 

 rabbits may be followed by local suppuration, by hsemorrhagic oedema, and by septi- 

 caemia. 



BACILLUS PNEUMONIA (FRIEDLANDER). 



In a small proportion of cases of lobar and lobular pneumonia, and 

 in a few cases of exudative inflammation of the pleura, pericardium, 

 meninges, and middle ear, this bacillus has been found. It is sometimes 

 found alone, but in pneumonia is frequently associated either with the 

 Micrococcus lanceolatus or with the pyogenic cocci. It has been found 

 in the nasal secretion and mouths of healthy persons. "While belonging 

 definitely among the bacilli, it so frequently occurs in the form of very 

 short rods or ovals or short chains that it was formerly thought to belong 

 among the cocci. 



. It seems highly probable rather than proven that it may be at least 

 partially responsible for the lesions with which it is infrequently asso- 

 ciated in man. This germ was formerly believed to be of great impor- 

 tance in connection with acute lobar pneumonia, and for a time was 

 generally spoken of as the pneumococcus of Friedlander. It is now 

 known not to be a coccus, and is certainly of subordinate if at all of 

 serious importance in the induction of inflammation of the lungs. 1 



MICROCOCCUS TETRAGENUS. 



This organism has been many times found about the mouth and re- 

 spiratory tract, especially in connection with suppurative processes. It 

 has been found also in metastatic abscesses. While not very virulent it 

 is apparently an occasional excitant, either alone or with other organ- 

 isms, of suppuration. 2 



Characters of the Organism. 



It is a coccus about 1 fj. in diameter, usually occurring in groups of four. These 

 tetrad groups may be encapsulated. It stains by Gram's method, and is readily culti- 

 vated on artificial media. It forms a dense whitish growth on gelatin which it does 

 not fluidify. Septicaemic lesions with local suppuration may be induced in guinea-pigs 

 by subcutaneous injection with cultures. 



THE PROTEUS GROUP OF BACILLI. 



This is a large and in the economy of nature an important group of 

 bacilli much concerned with the putrefactive processes. 



1 Howard, Philadelphia Medical Journal, vol. i., p. 336, 1898; Leon, "Le bacille de 

 Friedlander," These, Paris, 1897. 



For a study of this and related organisms, see Strong, Journal Boston Society, voL 

 iii., p. 185. 



''For resume of the significance of M. tetragemis and for bibliography, consult 

 Lariigau, Philadelphia Medical Journal, April 22d, 1899. 



