PATHOGENIC SPIRILLA. 593 



Inoculations into chickens and pigeons were without result ; in one 

 chicken the spirilla were found in the blood 011 the fourth day after inocula- 

 tion, but the fowl recovered. 



SPIRILLUM CHOLER^E ASIATICS. 



Synonyms. Spirillum ("bacillus") of cholera; Comma bacillus 

 of Koch ; Kommabacillus der Cholera Asiatica ; Bacille-virgule 

 cholerigene. 



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 



FIG. 172. FIG. 173. 



FIG. 172. Spirillum cholerae Asiaticae. x 1,000. From a photomicrograph. (Koch.) 

 FIG. 173. Spirillum cholerae Asiaticae, involution forms. X 700. (Van Ermengem.) 



other diseases than cholera. The etiological relation of this spiril- 

 lum to Asiatic cholera is now generally admitted by bacteriologists. 

 Morphology. Slightly curved rods with rounded ends, from 0.8 

 to 2 n in length and about 0.3 to 0.4 /*iii 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 



