568 PATHOGENIC AEROBIC BACILLI 



stained dots in a colorless ground. The threads, as a rule, present delicate, 

 sinuous, and wavy outlines ; the short forms are straight with rounded ends." 



Biological Characters. All attempts to cultivate this bacillus in the 

 usual media, either in the presence of oxygen or in an atmosphere of hydro- 

 gen, proved unsuccessful. But successive cultures were made by inoculations 

 in the pleural cavity of rabbits a bit of pleural exudate suspended in bouil- 

 lon was used for this purpose. The bacillus was also propagated upon the 

 lungs, heart, uterus, and kidney of healthy rabbits. The organs were re- 

 moved with great care to prevent contamination and placed in sterilized test 

 tubes. Transplantations from these cultures were only successful for one or 

 two generations. Better results were obtained ty cultivating the bacillus 

 upon the one-third to one-half grown foetuses of rabbits. 



Pathogenesis. "Considerable variations were observed according as the 

 inoculations were made into the pleural cavity, the peritoneal cavity, the sub- 

 cutaneous tissue, beneath the dura mater, or directly into the circulation. 

 The inoculations gave positive results in all cases except a few, in which they 

 were made subcutaneously. The death of the animal occurred soonest when 

 inoculation was made beneath the dura mater. A small portion of the skull 

 was trephined, care being taken to exclude extraneous microorganisms, and 

 a drop of the pleural fluid or a speck of the fibrinous exudate was introduced 

 beneath the membranes, care being taken not to injure the brain. These 

 animals, which quickly recovered from the effects of the operation, died on 

 an average about twelve hours after the inoculation. . . . 



" The pleural inoculations were followed by death, as before stated, in ev- 

 ery instance, the death of the animal occurring upon the third or fourth day. 

 The appearances presented at the autopsy were for the most part an exact 

 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 

 membrana 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." 



BACILLUS DYSENTERIC. 



The researches of Shiga, of Flexner, and of the board of medical 

 officers of the army engaged in the study of tropical diseases in the 

 Philippine Islands (1890) give support to the belief that there is a 

 form of acute dysentery which is due to infection by the bacillus of 

 Shiga, which Flexner describes as follows : ' 



"Bacillus of the average size of B. coli communis. There is variation in 

 length : almost none in thickness. The individuals are usually separate ; 



Johns Hopkins Hospital Bulletin, vol. xi., No. 115. 



