INFECTIOUS DISEASES OF MICE 415 



cultures after as many as twelve subcultures in tissue medium. Filtration 

 through Berkefeld V candles apparently removed the organism and excludes 

 the possibility of a filterable virus, since filtrates were not infective. The X 

 bacillus was not pathogenic. 



The possibility has not been excluded that this disease is related to that 

 described by Kairies and Schwartzer (116) as being due to an influenza-like 

 bacillus. It seems probable, however, that the mouse catarrh is a distinct 

 entity. The similarity of the coccobacilliform bodies to the pleuropneu- 

 monia-like organisms is striking and warrants further investigation. 



Pyogenic Infections, Botriomycosis 



Pyemic and suppurative lesions are frequent in mice as well as in other 

 laboratory animals. From subcutaneous abscesses may be cultured such 

 organisms as Staphylococcus aureus or albus, Gafkya tetragena {Micrococcus 

 tclragenus), hemolytic or non-hemolytic streptococci, rarely Bacillus pyo- 

 cyancus, and others of less importance. The lesions may arise at the site 

 of incarcerated worm rests and show a variable bacterial flora (299). 

 Abscesses in the heart and lungs, from which pure cultures of both white and 

 yellow micrococci were usually obtained, have been found in 3 per cent of 

 12,000 autopsies on mice (299). Certain of the cocci — Gajfkya tetragena, 

 for example — are very pathogenic for white mice, septicemia and death 

 occurring within 2 or 3 days after experimental inoculation by almost any 

 route (73). 



Abscesses about the head and neck have been observed not infre- 

 quently in the mice at the Jackson Memorial Laboratory and have been 

 found in one instance by Tyzzer (297). Pathologically, the condition 

 resembles that termed ''botriomycosis." The lesions are walled oft" and 

 composed of areas of granulation tissue enmeshed in fibrous strands with 

 numerous areas of dense polymorphonuclear exudation. Scattered through 

 the lesions are granules, irregular in outline, and surrounded usually by 

 polymorphonuclear exudate. Many show a rather homogenous outer rim, 

 staining pale blue with hemotoxylin and eosin, while the remainder of the 

 granule varies from deep blue to pink. Occasional club-like excrescences 

 may be seen. The structure of the granules may be granular and amor- 

 phous, or may suggest a central cellular appearance, likened by some inves- 

 tigators to cocci embedded in zooglial substance (287, p. 1181). Although 

 the disease in mice has not been adequately investigated, considerable 

 evidence is accumulating which indicates that in other animals the lesions 

 are due to staphylococci (287, pp. 1180--81; 124, 123). 



