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. Butsuccessive 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 Ly 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 microdrganisms, 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 heemoglobin-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.” 
BACILLUS DYSENTERIA. 
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; 
g Pp 
1 Johns Hopkins Hospital Bulletin, vol. xi., No. 115. 
