SYSTEMATIC AND DESCRIPTIVE. Iiy 



thicker and more irregular, and the appearance of 

 the streak is more opaque and whiter.* 



Streptococcus diphtheriticus. Oval cocci, 

 35 to i 'i //, in diameter, have been described as 

 characteristic of diphtheria.f The cells lie singly, 

 in pairs or in rosaries, and in spherical or cylin- 

 drical masses in diphtheritic membranes and the 

 surrounding connective and muscular tissues. 

 From the point of infection they can be traced 

 along the lymphatics, and are found in the blood, 

 heart, liver, kidneys, and other organs. In severe 

 cases the blood capillaries and uriniferous tubules 

 are blocked up. 



The attempt to get pure cultivations in nutrient 

 media and to make inoculation experiments has 

 not yet succeeded ; a bacillus and a bacterium have 

 also been described as the specific micro-organisms 

 of diphtheria (p. 136). 



Streptococcus of Progressive Tissue Ne- 

 crosis in Mice.! Cocci -5 //- in diam., in 

 chains or rosaries, and zooglcea; their invasion 

 causes tissue necrosis with destruction even of 

 cartilage cells, and spreading from the point of 

 inoculation, causes death in about three days. The 

 cocci are absent from the blood and internal 

 organs. These observations were made after the 

 injection of putrid fluids in the ear of mice, and 



* Rosenbach, ibid. 



t Oertel, Deutches Archiv f. Klin. Med. 1871. 

 I Koch, Untersuch. iiber die Aetiologie d. Wundinfections 

 krankheiten. 1878. 



