. Laboratory work in bacteriology. Bacteriology. PIPETTES. 457 â drawn-out portion should be about 40 cm. (16 in.) long. This is then heated in the middle, and, as a result, two sealed pipettes are thus obtained (Fig. 61, c or d). Frequently, it is desirable to transfer a liquid or a sus- pension from one tube to another. For small quantities the ordinary pipette (c or d) can be used direct. For larger â¢quantities a bulb should be blown into pipettes c or d, thus giving pipette d. While it requires a great deal of practice to blow a perfect bulb, still a serviceable one can be made without mu
. Laboratory work in bacteriology. Bacteriology. PIPETTES. 457 â drawn-out portion should be about 40 cm. (16 in.) long. This is then heated in the middle, and, as a result, two sealed pipettes are thus obtained (Fig. 61, c or d). Frequently, it is desirable to transfer a liquid or a sus- pension from one tube to another. For small quantities the ordinary pipette (c or d) can be used direct. For larger â¢quantities a bulb should be blown into pipettes c or d, thus giving pipette d. While it requires a great deal of practice to blow a perfect bulb, still a serviceable one can be made without mucl Fig. 6i. Drawn-out tube pipettes of Pasteur, aâPlugged, sterile tube as kept in â¢stock: ^âThe same heated at x in blast-lamp, drawn out; then sealed at x\ c and dâcom- pleted pipettes; eâThe same with bulb. A narrow flame of the blast-lamp la directed at the tube a short distance above the point where it begins to narrow. The tube is slowly turned until the glass softens; whereupon the ends are slightly pushed together so as to form a thick ring of glass. One or two addi- tional rings are made in this way. A large flame is then turned on so as to melt the thickened zones of glass. When the glass is per- fectly soft the end is brought rapidly to the mouth and the bulb is blown. The glass tube should be turned, slowly and steadily, while heating and also while the bulb, is being blown. The bulb pipettes â can often be used to better advantage if the capillary is bent at right' angles just below the bulb. When a pipette is to be used the mouth end should be heated in the ilame for a few moments. This is to prevent possible infection. The lower end of the capillary tube is then scratched with a file or glass-cutting knife and tlie sealed end removed. The end may be. 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
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Keywords: ., bookcentury1800, bookdecade1890, bookpublisherannarbormichgwahr
