A Laboratory Course in Bacteriology

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. 1901 Excerpt: ...and examine at the end of from eighteen to twenty-four hours. 4. The influenza colonies appear as minute colorless, glassy, transparent points, resembling drops of dew. They are barely visible to the unpractised eye, and require a low magnifying power to be seen clearly. Fig. 76.--Bacterium influenzae: colonies on blood-agar; low magnifying power (Pfeiffer). 5. Study the morphology and biology of the organisms in one of these colonies. They should not grow on ordinary media, and should have the morphology of the influenza bacteria. 6. Prepare smears from one of the purulent masses in the sputum. Stain in very dilute carbolfuchsin for five to ten minutes, or in Lomer's methylene-blue heated to the steaming-point. The influenza bacteria are very small, short, with Fig. 77.--Bacterium influenzae: cover-glass preparation of sputum from a case of influenza, showing the bacteria within the leucocytes; highly magnified (Pfeiffer). round ends, are often present in large numbers, and are frequently within the pus cells. They may occur in pairs, and then resemble cocci. The ends are usually more deeply stained than the central portions. Fig. 78.--Bacillus typhosus, from a twenty-four hour agar culture; x 650 (Heim). Fig. 79.--Bacillus coli, from an agar culture; x 1000 (Itzerott and Niemann). i. Study the morphology and biology of cultures of Bacillus typhosus and Bacillus coli. Some of the differences between them are indicated below: B. TYPhOSUS. Rods usually slender. Flagella more numerous, longer, more wavy (10-20). In artificial media growth generally slower and not so vigorous. Growth on fresh acid potato a nearly transparent film. Very slight acid production in ordinary media, followed sometimes by a production of alkali. Litmus milk--no change. Milk not coagu...