This historic book may have numerous typos and missing text. Purchasers can download a free scanned copy of the original book (without typos) from the publisher. Not indexed. Not illustrated. 1922 Excerpt: ... glycerol and starch were attacked by one. The presence of a few supposedly non-liquefiers among the motile strains may as probably--and even more probably--be an indication of the inaccuracy and unreliability of the gelatin liquefaction test than of the presence of true intermediate organisms, for the number of ...
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This historic book may have numerous typos and missing text. Purchasers can download a free scanned copy of the original book (without typos) from the publisher. Not indexed. Not illustrated. 1922 Excerpt: ... glycerol and starch were attacked by one. The presence of a few supposedly non-liquefiers among the motile strains may as probably--and even more probably--be an indication of the inaccuracy and unreliability of the gelatin liquefaction test than of the presence of true intermediate organisms, for the number of gelatin liquefiers recognized increases with the period of incubation. Again is it not reasonable to explain the presence of several glycerol and starch fermenters among the motile strains as due to mixed cultures? Picking off a colony from a plate, even after several replatings, is no absolute criterion that a pure culture was obtained. Some species stick tenaciously together. One of the motile starch fermenting strains referred to above was plated out on brilliant green agar. Ten colonies were fished into motility agar and starch; three were non-motile starch fermenters, three were motile and did not attack starch, while four were both motile and starch fermenters thus indicating that, in this instance at least, the presumably overlapping or intermediate TABLE 2 Showing correlation of indol, dulcitol, and inulin for strains of B. aerogenes 'Eight cultures not tested in inulin. TABLE 2a Coefficient of correlation for each pair of characters in table $ strains are in all probability merely mixed cultures. It is not contended that intermediate strains do not occur; they undoubtedly do; but it is desired to point out that these have been over emphasized in the past and that the plating method cannot always be relied upon to yield pure cultures. B. cloacae may be defined as a gram negative short rod which ferments lactose weakly; forms acetylmethylcarbinol from glucose; is alkaline to methyl-red; motile; rarely forms indol; practically always forms gas...
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