232 A MANUAL OF BACTERIOLOGY 



organism. It is pathogenic to white mice, hardly so to 

 guinea-pigs and white rats, and moderately so to rabbits ; 

 intra-venous inoculation into the latter sometimes sets 

 up an endocarditis. Harris and Longcope 1 have reported 

 five more instances of the occurrence of this organism 

 (once from a cesspool, four times as secondary invasions 

 at autopsies), and Birge 2 has isolated a similar but less 

 virulent organism from the larynx of crows. Braxton 

 Hicks 3 has also isolated this organism from a case of 

 malignant endocarditis. 



Micrococcus neoformans 



This organism was isolated by Doyen from malignant 

 growths, and was supposed by him to be the causative 

 organism of malignant disease. It is a typical Gram- 

 positive coccus, giving a white growth on agar and 

 liquefying gelatin in three to four days. According to 

 Dudgeon and Dunkley, 4 it gives all Gordon's fermenta- 

 tion tests for the M. pyogenes, var. albus, except that it 

 does not acidify mannitol. 



The serum of patients suffering from malignant disease does not 

 give any marked agglutination with the M. neoformans, nor does 

 it contain opsonins specific for the organism. The M . neoformans 

 is non-pathogenic for rats and mice. 



The Streptococci 



Many streptococci of very variable virulence occur in 

 man and animals. Formerly only one pathogenic species 

 was described, Streptococcus pyogenes, now several varieties, 

 if not species, are recognised. 



1 Centr. f. Bakt. (]> Abt.), vol. xxx, 1901, p. 353. 



2 Johns Hopkins Hosp. Bull., vol. xvi, 1905, p. 309. 



3 Trans. Eoy. Soc. Med., vol. v, 1912, Path. Sect., p. 126. 

 Journ. of Hygiene, vol. vii, 1907, p. 13. 



