. Manual of bacteriology. Bacteriology. 322 TYPHOID FEVER. length of the bacilli is such as to throw doubts on the purity of the culture. Its purity, of course, can be readily tested by pre- paring plates from it in the usual way. As a general rule in a young (twenty- four to forty- eight hours old) colony, grown at a uniform temperature, the bacilli are plump, and the protoplasm stains uniform- ly. In old cul- tures or in cul- tures which have been ex- posed tochange of temperature, the protoplasm stains only in parts; there may be an ap- pearance of irregular vacuolation either at the centre
. Manual of bacteriology. Bacteriology. 322 TYPHOID FEVER. length of the bacilli is such as to throw doubts on the purity of the culture. Its purity, of course, can be readily tested by pre- paring plates from it in the usual way. As a general rule in a young (twenty- four to forty- eight hours old) colony, grown at a uniform temperature, the bacilli are plump, and the protoplasm stains uniform- ly. In old cul- tures or in cul- tures which have been ex- posed tochange of temperature, the protoplasm stains only in parts; there may be an ap- pearance of irregular vacuolation either at the centre or at the ends of the bacilli. There is no evidence that spore formation occurs in the typhoid bacillus. Motility. — In hanging-drop preparations the bacilli are found to be actively motile. The smaller forms have a darting Or roll- ing motion, passing quickly across the field, whilst some show rapid rotatory motion. The filamentous forms have an undu- lating or serpentine motion, and move more slowly. Hanging- drop preparations ought to be made from agar or broth cultures not more than twenty-four hours old. In older cultures the movements are less active. Flagella. — On being stained by the appropriate methods (^'x^/i? p. 107) the bacilli are seen to possess many long wavy flagella which are attached all along the sides and to the ends (Fig. 115). They are more numerous, longer, and more wavy than those of the B. coli. Characters of Cttltitrcs. — Stab-cultures in peptone gelatin give. Fig. 115. — Tjq^hoid bacilli, from a young culture on agar, showing flagella. Stained by Van Ermengem's method. X Please note that these images are extracted from scanned page images that may have been digitally enhanced for readability - coloration and appearance of these illustrations may not perfectly resemble the original Muir, Robert, 1864-; Ritchie, James, 1864-1923; Harris, Norman MacLeod. New York, The Macmillan Company; London, Macmillan
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