BACILLUS PARATYPHOSUS. 287 



flagella and is not motile. Polar granules can be made out 

 when the germ is stained with methylene-blue. Gram's stain 

 is not applicable. 



Bacillus dysenteries develops rapidly at the body tempera- 

 ture, but very slightly at the room temperature. The culture- 

 medium should be slightly alkaline, as the bacillus is not in 

 the least resistant to acids. 



Both deep and superficial colonies on gelatin plates are very 

 small, round and regular, and whitish in color. The medium 

 is not liquefied. 



In the gelatin stab many minute grayish colonies develop 

 along the track of the needle without any surface growth. 



On agar-agar large single, bluish-white, regular colonies 

 develop at the end of twenty-four hours. There is no growth 

 on blood-serum. On boiled potato the growth at first resembles 

 that of the typhoid bacillus, but soon takes on the appearance 

 of the growth of the colon bacillus on potato. Bouillon is 

 clouded. Milk remains unchanged. The organism does not 

 produce indol, nor does it evolve gas when grown on media 

 containing sugar. Acid-production is very slight. 



Bacillus dysenteries agglutinates with the blood-serum of 

 persons suffering with or convalescent from dysentery. 



Shiga has obtained an immunizing serum from horses inocu- 

 lated with old agar-agar cultures dried in vacuo, and has 

 succeeded in reducing the mortality from 34.7 to 9 per cent. 

 This applies only to cases of epidemic dysentery, and not to 

 tropical dysentery, which is caused by an animal parasite, 

 the Amoeba coli. 



Bacillus Paratyphosus. 



It has hitherto always been taken for granted that typhoid 

 fever may differ in its clinical manifestations, at times ap- 

 pearing like a case of mild or abortive typhoid. Recently, 

 however, several investigators have been able to isolate an 

 organism from the intestinal discharges and blood of patients 

 apparently suffering from mild forms of typhoid fever, which 

 differs from both the typhoid and colon bacilli, and also from 

 Shiga's bacillus. Nevertheless it is a member of the colon 

 group. 



