MICROCOCCI PATHOGENIC IN THE LOWER ANIMALS. 205 



the cut hepatised lung has heen frequently employed for 

 protective inoculations ; it is injected subcutaneously 

 into the tail, and causes at the most a local affection, and 

 after this has passed off immunity is said to be attained. 



Swine erysipelas (pig typhoid, &c.). Pasteur and 

 Thuillier have found micrococci in the blood and in the 

 exudations, and have ascribed io them a causal signifi- 

 cance. Loeffler and Schiitz, Lydtin and Schottelius 

 have, however, described bacilli as the true causal agents 

 of this disease (see later). 



A number of well characterised pathogenic micrococci 

 have been observed in various of the animals ordinarily 

 employed for experiment. To these belong, besides the 

 above-mentioned staphylococcus, which can be inoculated 

 on lower animals with success, streptococcus malignus 

 and septicus. 



Micrococcus tetragenus. 



First described by Gaffky.* It is not uncommonly Micrococcus 

 found in human sputum, and is especially observed 

 in the sputum and in the walls of the cavities in cases of 

 pulmonary tuberculosis. Micrococci about 1 /*.. or Microscopic 

 more in diameter, dividing into four individuals which appea 

 remain united by a gelatinous envelope. In cultivations 

 we find some large spherical cells undergoing division, 

 but the greatest number consist of cells in which the 

 division has been completed. The round gelatinous 

 envelope stains faintly, the microccoci strongly with 

 aniline dyes ; the colour is retained in Gram's method ; 

 the appearance recalls that of sarcina, but the division 

 in the third plane and the formation of many-celled 

 packets is absent. On gelatine plates M. tetragenus Cultivations, 

 forms in 24 48 hours small white points which under 

 a low power present the appearance of circular or citron- 

 shaped yellow masses, with a granular, mulberry-like 

 surface, and regular, but somewhat rough, jagged 



* "Klinische, experimentelle u. botanische Studien iiber die Be- 

 deutung des Torfmulls als Verbandmittel." Von Dr. Neuber, Dr. 

 Gaffky, u. Dr. Prahl, v. Langenbeck's Arch./. Chir., vol. 28, Heft 3. 



