Cultivation 493 



medium appear small, generally spheric, with a rough, 

 irregular outline, and by transmitted light of a vitreous 

 greenish or yellowish-green color. The most characteristic 

 feature consists of well-defined filamentous outgrowths, 

 ranging from a single thread to a complete fringe about the 

 colony. The young colonies are, at times, composed solely 

 of threads. The fringing threads generally grow out nearly 

 at right angles to the periphery of the colony. 



The colonies of the colon bacillus appear, on the average, 

 larger than those of the typhoid bacillus; they are spheric 

 or of a whetstone form, and by transmitted light are darker, 

 more opaque, and less refractive than the typhoid colonies. 

 By reflected light they are pale yellow to the unaided eye. 



Surface colonies are large, round, irregularly spreading, 

 and are brown or yellowish-brown in color. Hiss claims 

 that by the use of these media the typhoid bacillus can 

 readily be detected in typhoid stools. 



Piorkowski* recommends a culture medium composed of urine two 

 days old, to which 0.5 per cent, of peptone and 3.3 per cent, of gelatin 

 have been added. Colonies of the typhoid bacillus appear radiated and 

 filamentous ; those of the colon bacillus, round, yellowish, and sharply 

 denned at the edges. The cultures should be kept at 22 C., and the 

 colonies should appear in twenty-four hours. 



Adami and Chapinf have suggested what seems to be a 

 promising method for the isolation of typhoid bacilli from 

 water, making use of the agglutination of the bacilli by 

 immune serum. Two quart bottles (Winchester quarts) 

 are carefully sterilized and filled with the suspected water 

 with an addition of 25 c.c. of nutrient broth and incubated 

 for eighteen to twenty-four hours at 37 C. By this time 

 the typhoid bacillus grows abundantly in spite of the small 

 amount of nourishment the water contains. At the end of 

 the incubation, 10 c.c. of the fluid is filled into each of a 

 number of long narrow (7 mm.) test-tubes made by sealing 

 a glass tube one-half meter long at one end. About one inch 

 from the bottom the tube is filed completely round so as to 

 break easily at that point. The different tubes next receive 

 additions of typhoid immune serum sufficient to make the 

 dilutions i : 60, i : TOO, i : 150, and i 1200. If typhoid 

 bacilli are present, within a quarter of an hour beginning 

 agglutination can be seen, and by the end of two to five hours 



*" Berliner klin. Wochenschrift/' Feb. 13, 1899. 



f "Journal of Medical Research," May, 1904, vol. xi, No. 2, p. 469. 



