PATHOGENIC SPIRILLA. 593 
Inoculations into chickens and pigeons were without result ;,in one 
chicken the spirilla were found in the blood on the fourth day after inocula- 
tion, but the fowl recovered. 
SPIRILLUM CHOLERA ASIATIC A. 
Synonyms.—Spirillum (“bacillus”) of cholera ; Comma bacillus 
of Koch; Kommabacillus der Cholera Asiatica; Bacille-virgule 
cholerigéne. 
Discovered by Koch (1884) in the excreta of cholera patients and 
in the contents of the intestine of recent cadavers. , 
The researches of Koch, made in Egypt and in India (1884), and 
subsequent researches by bacteriologists in various parts of the 
world, show that this spirillum—so-called ‘‘ comma bacillus ”—is con- 
stantly present in the contents of the intestine of cholera patients 
during the height of the disease, and that it is not found in the con- 
tents of the intestine of healthy persons or of those suffering from 
® 
i e »@ oS 
6.3 5 
Fic. 172. Fie. 173, 
Fie. 172.—Spirillum cholerze Asiatic. % 1,000. From a photomicrograph. (Koch.) 
Fig. 173.—Spirillum cholere Asiaticz, involuticaforms. x 700. (Van Ermengem.) 
other diseases than cholera. The etiological relation of this spiril- 
lum to Asiatic cholera is now generally admitted by bacteriologists. 
Jforphology.—Slightly curved rods with rounded ends, from 0.8 
to 2 in length and about 0.3 to 0.4 in breadth. The rods are 
usually but slightly curved, like a comma, but are occasionally in 
the form of a half-circle, or two united rods curved in opposite 
directions may form an S-shaped figure. Under certain circum- 
stances the curved rods grow out into long, spiral filaments, which 
may consist of numerous spiral turns, and in hanging-drop cultures 
the S-shaped figures may also be seen to form the commencement 
_of a spiral; in stained preparations the spiral character of the long 
filaments is often obliterated, or nearly so. When development is 
very rapid the short, curved rods or S-shaped spirals only are seen ; 
but in hanging-drop cultures, or in media in which the develop. 
38 
