398 



PATHOGENIC MICROORGANISMS 



It may be pyogenic and in every way similar to Staphylococcus 

 pyogenes aureus, but is less often found in connection with 

 pathological lesions than either of the preceding staphylococci. 



A large number of staphylococci, differing from those described 

 above in one or another detail, have bejen observed. They are of 

 common occurrence and are met with chiefly as contaminations in 

 the course of bacteriological work. Few of these have any patholog- 

 ical significance and none of them are toxin-producers, so far as we 

 know. Many of them differ, furthermore, in their inability to 

 liquefy gelatin. All of them belong more strictly to the field of 

 botany than to that of pathological bacteriology. 



Atypical pathogenic staphylococci have been described by a num- 

 ber of observers. Thus Weichselbaum 40 isolated a Staphylococcus 

 from a case of malignant endocarditis which could not be cultivated 

 at room temperature, and grew only in very delicate colonies. Veil- 

 Ion, 41 moreover, has described a strictly anaerobic Staphylococcus 

 cultivated from the pus of an intra-abdominal abscess. 



MICROCOCCUS TETRAGENUS.-^LI 1881 Gaffsky 42 discovered a micro- 

 coccus which occurs regularly in groups of four or tetrads. He 



FIG. 45. MICROCOCCUS TETRAGENUS. 



first isolated it from the pus discharged by tuberculous patients 

 with pulmonary lesions. Observed in smear preparations from pus, 



40 Weichsellaum, Baumgarten, Jahresb., 1899, Ttef. 



**Veillon, Compt. rend. soc. de biol., 1893. 



42 Gaffsky, Mitteil. a. d. kais. Gesundheitsamt, i, 1881. 



