THE GROUP OF THE DYSENTERY BACILLI 
353 
the pathogenic organisms but the habitually i)arasitic organisms as 
well, follow: 
i 
1 
_. 
i 
g 
5- 
s 
2 
i 
a 
■•= 
■3 

'S 
•43 
a 
^ 
j2 

1 

3 
1 
1 

1 
B. alcaligenes 
+ 
B. dysenterise Shiga . 
- 
+ 
- 
- 
* - 
— 
Schmitz bacillus .... 
- 
+ 
_ 
- 
- 
± 
+ 
Possibly B. ambiguus? 
B. dysenterise Flexner 
- 
+ 
+ 
- 
- 
d= 
± 
Indol production variable; 
a large group of imper- 
fectly diffe rentiated 
strains. 
B. dysenteriae Hiss-Russell . 
+ 
+ 
- 
+ 
=^ 
- 
+ Fermentation of sacchar- 
ose somewhat irregular. 
B. dysenterise Rosen . 
+ 
+ 
+ 
+ 
- 
.+ 
— 
-|- Probably not a true dysen- 
tery bacillus. 
B. pyogenes foetidus . 
+ 
+ 
+ 
+ 
+ 
+ 
- 
+ Not a member of the dys- 
entery group. 
B. typhosus A . . . 
+ 
+ 
+ - 
- 
+ 
- 
— 
B. typhosus B . . . . 
+ i +' +i -1 - 
± — 
- 
B. paratyphosus alpha 
+ 1 g i g -j - 
+ 
- 
- 
B. paratyphosus beta 
+ ig!g': - - 
=t 
- 
- 
Morgan bacillus No. 1 
+ : g 1 -i -' - 
^ 
- 
+ 
B. coli commune . 
+ i g ; g i g 
- 
c 
- 
+ 
B. coli communior 
+ , g , g i g 
g 
c 
- 
+ 
B. proteus ... 
+ : g - : - 
g 
p 
+ 
+ 
B. cloacse 
+ 
g 
g 
g 
g 
c/p 
+ 
+ 
Legend: Carbohydrate solutions: — = no fermentation, -|- = acid produced, g = gas 
produced. 
Milk: — = no fermentation, alkaline reaction, =*= = initial acidity, terminal 
alkalinity, + = acid, c = coagulation, p = peptonization. 
Morphology.— The morphology of the members of the dysentery 
group of })acilli is practically identical; they are medium-sized, rod- 
shaped organisms, measuring from 0.8 to 1 micron in diameter, and 
from 1.5 to 3 microns in length. They have rounded ends and occur 
singly or in pairs, rarely in short chains. Frequently, elongated, 
somewhat irregular involution forms are found in old broth cultures. 
The bacilli are ncm-motile (except the "Rosen" strain, which is slug- 
gishly motile), possess no flagella, form no capsules and produce no 
spores. They stain fairly readily with ordinary anilin dyes; frequently 
the ends of the organisms stain somewhat more heavily than the 
center. All the organisms comprising this group are (iram-negative. 
Isolation and Culture. —The dysentery bacilli grow well on ordinary 
laboratory media. Colonies on agar, after eighteen to twenty-four 
hours' incubation at the body temperature, are round, transparent 
23 
