NOT DESCRIBED IN PREVIOUS SECTIONS. 527 



reproduction of those observed in the animal which had succumbed to the 

 natural disease. Upon the side of inoculation a thick, grayish-yellow, shaggy 

 membrane covered the pleural surfaces, being at times four or five millime- 

 tres in thickness. The pleural cavity contained several cubic centimetres of 

 a clear haemoglobin-colored fluid, the lung for the most part being com- 

 pressed. At times smaller or larger areas of lobular pneumonia would be 

 present ; and, as a rule, the inflammation was not limited to the serous mem- 

 brane of the side of inoculation, but extended into the opposite pleural cavity 

 and into the pericardial sac. However, in these situations the process was, 

 as a rule, less intense, the solid exudate being less considerable, and in the 

 case of the opposite pleural cavity sometimes entirely wanting. The super- 

 ficial vessels, however, were injected and the serous surface of the affected 

 membrane covered with a slimy, clear fluid. In addition to this the oppo- 

 site pleural cavity always contained a similar pink serum to that described 

 upon the side of inoculation. 



"The study of the exudate upon the side of inoculation as well as the 

 fluid contained in the opposite pleural cavity and in the pericardium showed 

 the same organisms as had been introduced." 



175. BACILLUS OF UNNA AND HODARA. 



Obtained by Hodara (1894) from the contents of acne pustules ** in enor- 

 mous masses in the comedones of true acne." 



Morphology. Small bacilli, from 0.3 to 0.7 t* long and 0.3 ft thick. 

 When stained, by Unna's method, with methylene-blue-glycerin ether, or with 

 methylene-blue-tannin solution, they are seen to be surrounded by a homo- 

 geneous, jelly-like mass which is stained pale violet by the first method and 

 green by the second. The bacilli are sometimes united in chains of two or 

 three elements, and single rods may present in the middle an unstained zone 

 with deeply stained extremities. 

 Biological Characters. Not determined. 



176. PROTEUS FLUORESCENS (Jaeger). 



Obtained by Jaeger (1892) from the liver, spleen, and kidneys of fatal 

 cases of infectious icterus ("Weil's disease"). 



Morphology. A. pleomorphous bacillus of theproteus group ; in the same 

 culture cocci-like elements, short rods either straight or curved, and long 

 filaments are seen. 



Biological Characters. An aerobic and facultat ive anaerobic, motile, 

 liquefying, chromogenic bacillus. Is not to be distinguished from Proteus 

 vulgaris except by the fact that it produces an intense fluorescent-green pig- 

 ment. Jaeger says that cultures which originally failed to liquefy gelatin and 

 produced the fluorescent-green pigment, at the end of two and a half years 

 had lost the property of producing pigment and had acquired the property of 

 liquefying gelatin, and could not be distinguished from Proteus vulgaris. 

 But when these cultures were kept at a lower temperature they gradually 

 regained their former characters. 



Pathogenesis. Pathogenic for mice and for pigeons; but the virulence 

 of cultures proved to be very variable. 



177. MICROCOCCUS INSECTORUM (Burrill). 



Obtained by Burrill (1883) from the alimentary canal of infected "chinch 

 bugs" (Blissus leucopterus). , 



Morphology. Oval or spherical (micrococci ?) bacteria, usually in pairs, 

 but sometimes in chains of four to eight elements. ' ' Undivided segments vary 

 from 0.8 to 1.6 / in length, with a uniform width of 0.65 p. " (Forbes). 



