. Pathological technique; a practical manual for workers in pathological histology and bacteriology. chancroid in smear preparation from pus (Lincoln Davis ;photo by L. S. Brown). Bacillus of Chancroid (Bacillus of Ducrey).—In smears from the lesions the bacilli appear as short, round-ended rods, about 1,5 p. long and fi thick, occurringcharacteristically but not always in chains. The middleportion of the rods does not stain so deeply as the bacilli are decolorized by Grams method of staining,and are not motile. The following description of the cul- 320 PA THOL 0GICAL TECHNIQ UE.
. Pathological technique; a practical manual for workers in pathological histology and bacteriology. chancroid in smear preparation from pus (Lincoln Davis ;photo by L. S. Brown). Bacillus of Chancroid (Bacillus of Ducrey).—In smears from the lesions the bacilli appear as short, round-ended rods, about 1,5 p. long and fi thick, occurringcharacteristically but not always in chains. The middleportion of the rods does not stain so deeply as the bacilli are decolorized by Grams method of staining,and are not motile. The following description of the cul- 320 PA THOL 0GICAL TECHNIQ UE. tural peculiarities of the chancroid bacillus are based on theobservations of Dr. Lincoln Davis in the Laboratory of theMassachusetts General Hospital. The bacillus does not grow on the ordinary culture-media, but may be cultivated in blood or in media contain-ing one-third its volume of blood. It is essential that theblood be fresh. In tubes containing blood, or a mixture ofbouillon and blood, after twenty-four hours in the incubator,the growth appears as whitish flocculi at the bottom of the. Fig. 77.—Bacillus of chancroid from culture (Lincoln Davis ; photo byL. S. Brown). tube. These flocculi are composed of tangled chains of thebacilli, the chains being often of extreme length. Theindividual bacilli, as a rule, have the same morphology andstaining reactions as in the smears from lesions, but occa-sionally long or even filamentous forms may be seen. Onthe surface of slant tubes, composed of a mixture of freshblood and agar, the bacillus forms, after forty-eight hours inthe incubator, small, rounded, grayish colonies difficult topick up with the platinum wire, because they tend to glidebefore it. The bacilli from these colonies appear in smearpreparations in short chains and singly. Involution formsare early apparent among the bacilli in all cultures. The PATHOGENIC BACTERIA AXD FUNGI 321 bacillus dies out in cultures after about three days. Upona monkey of the genus Mac
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