284 IMPORTANT VARIETIES OF FISSION-FUNGI. 



upon wafers abundant pyocyanin, which can be easily extracted with 

 chloroform from nutrient media containing water. There are also 

 cultures which, at least on certain nutrient media (it is recommended 

 to employ \% peptone, 1.5$ agar boiled in water, and, finally, 5$ 

 gelatin added), produce only pyocyanin, and, finally, there are those 

 which produce no pigment. The brown color of old cultures comes 

 from a changing of pyocyanin into a reddish-brown pigment. Pyo- 

 cyanin is easily changed into yellow pyoxanthose. Eegarding pyocy- 

 anin, see also Borland, C. B. xxv, 897. 



Regarding interference with the formation of pigment brought 

 about by other bacteria (for example, Micr. pyogenes, Bac. anthracis), 

 see Miihsam and Schimmelbusch (C. B. xv, 430). 



(6) Other products: Upon all nutrient media there is 

 present at first a delicate aromatic odor (compared to 

 linden blossoms). We have also often perceived this 

 odor in other cases; for example, in Sarcina lutea, Micro- 

 coccus luteus. Old cultures smell disagreeably of am- 

 monia. It forms neither indol nor H 2 S, and from grape- 

 sugar little acid and no gas are produced. Even the 

 boiled bouillon cultures are strongly poisonous. They 

 contain, besides proteins, toxic metabolic products. Nitro- 

 gen is liberated from nitrates and nitrites (Lehm. and 

 Neum. ). Weissenberg has, in our institute, demonstrated 

 this property in all the four cultures of B. pyocyaneum 

 examined (A. H. xxx, 274). 



Experimental Observations with Animals. It is 

 usually weakly pathogenic for animals; when injected, it 

 causes suppuration. Schiirmayer found in mice, after 

 subcutaneous injection, clear edema and serous exudate 

 into the body cavities. Virulent cultures kill guinea-pigs 

 when injected subcutaneously and intraperitoneally. 



Immunity. The very interesting studies of Wasser- 

 mann (Z. H. xxn, 263) are mentioned on page 110. For 

 more details the original must be consulted. 



Distribution. 



(a) Outside the body: So far, has not been certainly 

 found. 



(b) In healthy body : Sometimes in the mouth and intes- 

 tine and upon the skin of healthy persons. 



(c) In diseased body: Not infrequently (especially 

 formerly) in pus from open wounds, also in the dressings 

 from wounds, sometimes in epidemics in -the rooms of the 

 sick. Usually the organism appears only in association 



