PATHOGENIC BACTERIA. 135 



through a Chamberland filter and injected into a rabbit suffer- 

 ing with pneumonia, cured the same; or when injected into a 

 susceptible animal produced in it immunity very quickly. This 

 principle is ascribed to an anti-toxin formed in the tissues by 

 the diluted proteids, and this anti-toxin neutralizes the toxicity 

 of the strong virus. 



Bacillus of Ehinoscleroma. (Frisch. 1882.) It was found in 

 the tissue of a rhinoscleroma, but resembles the Friedlander 

 bacillus in nearly every respect, and as the disease rhinoscleroma 

 was not reproduced by the inoculation of the bacillus in animals, 

 it can be considered identical. The growth, cultures, and pro- 

 perties are the same as the pneumobacillus of Friedlander. 



Diplococcus Intracellularis Meningitidis. Weichselbaum 

 claims to have found a special diplococcus in epidemic cerebro- 

 spinal meningitis, which differs in a few respects from the pneu- 

 mococcus of Frankel : growth most abundant on blood-serum 

 round, white, shining colonies in twenty-four hours. It does 

 not take Gram's stain ; does not affect animals when injected 

 eubcutaneously. Inoculated into the meninges of the dog and 

 goat, a meningitis has been produced, and when found in the 

 exudate of the meninges lies in the protoplasm and nuclei of 

 the leucocytes. The organism has many points in common 

 with the gonococcus, but differs from it in the ease of cultivation. 



Micrococcus Tetragenus. (Koch. Gaffky). 



Origin. Koch found this microbe in the cavity of a tuber- 

 culous lung. Gaffky, in 1883, studied its pathogenic actions 

 and gave it the name it now bears. 



Form. Cocci which are gathered in the tissues in groups of 

 four, forming a square, a tetrad. See Fig. 71. In artificial 

 culture, sometimes found in pairs. A capsule of light gelat- 

 inous consistence surrounds each tetrad. 



Properties. They are immobile ; do not liquefy gelatine. 



Growth. They grow well on all nutrient media at ordinary and 

 brood temperatures ; are facultative aerobic. They grow slowly. 



Colonies in gelatine plates. In two days, little white spots, 

 which when on the surface form little elevations of a porce- 

 lain-like appearance; under low power they are seen very 

 finely granulated. 



