BACILLUS PYOCYANEUS. 423 



in pure cultures during life or from the blood and 

 organs shortly after death. It has been found as 

 the sole organism in meningitis and vegetative en- 

 docarditis. Some of the cases indicate, however, 

 that a previous lowering of resistance, as that 

 caused by tuberculosis and syphilis, is important 

 for general invasion by the bacillus. It has been 

 found several times in suppurative processes in the 

 middle ear, and would seem to be either the cause 

 or a strong adjuvant in some cases of severe enter- 

 itis, especially in childern. In systemic infec- 

 tions, the symptoms are typhoidal in character, 

 with high temperature, diarrhea and a tendency 

 to the formation of hemorrhages in the skin and 

 internal organs. 



The Bacillus pyocyaneus is widely distributed 

 and that it causes so few infections is probably due 

 to its low pathogenic power. It is an organism of 

 manifold activities. It produces a substance, pyo- 

 cyanin, which, when exposed to the air, assumes a 

 bluish tint, and on which the color of the pus de- 

 pends; pyocyanin is soluble in chloroform, from 

 which it may be precipitated in crystalline form. 

 Under proper conditions the organism also forms 

 a fluorescent pigment. It produces a strong pep- Ferments. 

 tonizing ferment, coagulates milk, and in old 

 cultures an autolytic ferment is found which di- 

 gests many of the bacilli. As stated in a previous 

 chapter, Emmerich and Lowe have identified a 

 bacteriolytic ferment, pyocyanase, which dissolves 

 the anthrax bacillus and other organisms. The 

 ferment nature of this substance is in some doubt, 

 inasmuch as it resists the boiling temperature. 

 Dietrich thinks its action is due to the production 

 of osmotic changes. Old cultures contain a hamo- 



