74 MICRO-ORGANISMS AND DISEASE. [CHAP. 



from the blood) in meat broth, meat extract solution, &c., at 

 37 to 39 C., and obtained good crops of them, with which 

 they produced by inoculation in seven rabbits and six white 

 rats, typical pneumonia yielding the characteristic micro- 

 cocci. These micrococci stain best in a mixture of Bismarck 

 brown and methyl violet, but they stain also very well in 

 gentian violet. 



Quite recently Friedlander and Frobenius I cultivated the 

 micrococci in nutritive gelatine, and obtained good crops. 

 The shape of such growths is nail-like, consisting of a vertical 

 streak, the nail-pin corresponding to the channel of inocu- 

 lation, and in connexion with this is a disc-shaped patch 

 the nail-head extending on the surface of the gelatine. 

 Inoculations of these capsulated pneumococci into the lung 

 tissue of rabbits produced no result, into that of mice produced 

 pneumonia and pleurisy after twenty-four to forty-eight hours. 

 In guinea-pigs the results were not so decisive. About half of 

 the animals escaped, the others died with dyspnoea, the 

 blood, lungs, and pleural exudations containing the same 

 pneumococci. From my own observations I cannot accept 

 these statements without qualification, for I find : That even 

 in typical cases of croupous pneumonia of man, the micrococci 

 may be absent or may be only very scarce even between the 

 third and ninth day; that typical sputum of croupous 

 pneumonia does not in many instances produce disease 

 in animals on inoculation ; and that the disease produced 

 in rabbits and mice is of the nature of septicaemia, 

 due to a specific septicaemic micrococcus not necessarily 

 always present in the sputum and lungs of human croupous 

 pneumonia. 



It seems therefore clear, that when sputum produces 

 on inoculation disease and death of rodents, this is due to 

 1 Berichte d. physiclog. Gesellschaft in Berlin, Nov. 9, 1883. 



