. Pathogenic micro-organisms, including bacteria and Protozoa; a practical manual for students, physicians and health officers. nder bacillus with one endtapering and the other club-shaped. It varies in length from 2/i toSix and even 4,«. It occurs mostly as a diplobacillus (see Fig. 94) with the pointed ends adja-cent and the swollen ends free, but at times this order is reversed and a fusi-form appearance results. As the line of separation is often obscure and asthe two organisms come together at different angles these various arrange-ments give the impression of many different forms. The ba
. Pathogenic micro-organisms, including bacteria and Protozoa; a practical manual for students, physicians and health officers. nder bacillus with one endtapering and the other club-shaped. It varies in length from 2/i toSix and even 4,«. It occurs mostly as a diplobacillus (see Fig. 94) with the pointed ends adja-cent and the swollen ends free, but at times this order is reversed and a fusi-form appearance results. As the line of separation is often obscure and asthe two organisms come together at different angles these various arrange-ments give the impression of many different forms. The bacilli lie sometimes in parallel groups, but are seldom entangled. Inold cultures, the swollen ends seen in the young cultures become bifurcated,others take the stain irregularly and Tissier designates this the vesicular some instances several baciUi become grouped together at different angles,giving the appearance of multiple branching forms. As the medium becomesmore acid, the bifurcated forms become more numerous. Vesicular formsbear a relation to vitality and bifurcated forms a relation to media. It is Fig. 94. B. Bifidus, representing the various forms described; the irreejularly-stained or vesicular formsbeing from old cultures. X about 1800 diam. non-motile, stains by Grams method, old cultures staining irregularly. Doesnot seem to possess spores. Killed at 60° for 15 minutes. Does not die outquickly. Can be transplanted after three weeks. Grows best at 37° C, butalso grows at 20° C. On glucose agar, after three days, fine regular colonies, oval in shape,appear. It is innocuous to guinea-pigs. It can be cultivated on beerwortagar and on glucose agar. In stab cultures made from the faeces, in eithermedium the bacilli may be found in almost pure cultures at the bottom ofthe stab after two to fifteen days; the other organisms dying out unless theenterococcus, which is a facultative anaerobe, is present, then B. bifidus, beingless adaptable, is overgrown. Fermenta
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