Cultivation 591 



preparations the bacilli are always found in scattered groups, which 

 are easily discovered, under a low power of the microscope, as 

 reddish specks, and readily resolved into bacilli with the oil-im- 

 mersion lens. 



In bacilli stained with the alkaline methylene-blue solution, 

 dark-colored dots (Babes-Ernst or metachromatic granules) may 

 sometimes be observed near the ends of the rods. 



Isolation. — The bacillus can be secured in pure culture from an 

 enlarged lymphatic gland or from the splenic pulp of a case of typhoid . 



As the groups of bacilli are sometimes widely scattered through- 

 out the spleen, E. Frankel recommends that as soon as the organ 

 is removed from the body it be wrapped in cloths wet with a solution 

 of bichlorid of mercury and kept for three days in a warm room, in 

 order that a considerable and massive development of the bacilli 



Fig. 249. — Bacillus typhi abdominalis; superficial colony two days old, as seen 

 upon the surface of a gelatin plate. X 20 (Heim). 



may take place. The surface is then seared with a hot iron and ma- 

 terial for cultures obtained by introducing a platinum loop into the 

 substance of the organ through the sterilized surface. 



Cultures may be more easily obtained from the blood of the 

 living patients. . (See "Blood culture," under the section "Bacterio- 

 logic Diagnosis.") 



The bacilli can also be secured from the alvine discharges of 

 typhoid patients during the second and third weeks of the disease. 



Cultivation. — The bacillus grows well upon all culture-media 

 under both aerobic and anaerobic conditions. 



Colonies. — The deep colonies upon gelatin plates appear under the 

 microscope of a brownish-yellow color and spindle-shape, and are 

 sharply circumscribed. When superficial, however, they become 

 larger and form a thin, bluish, iridescent layer with notched edges. 

 The superficial colonies are often described as resembling grapevine 

 leaves in shape. The center of the superficial colonies is the only 



