. A manual of clinical diagnosis by means of microscopical and chemical methods, for students, hospital physicians, and practitioners . h a thin layer 7 98 THE BLOOD. of paraffin, which is later dissolved by immersion in toluol. In thismanner especially valuable and rare specimens may be kept almostindefinitely without change; but even without this precaution theblood films will remain in good condition for a long time. Before staining, it is often necessary to fix the albuminousbodies of the blood. To this end, different methods may be em-ployed. Immersion in absolute alcohol for from five to
. A manual of clinical diagnosis by means of microscopical and chemical methods, for students, hospital physicians, and practitioners . h a thin layer 7 98 THE BLOOD. of paraffin, which is later dissolved by immersion in toluol. In thismanner especially valuable and rare specimens may be kept almostindefinitely without change; but even without this precaution theblood films will remain in good condition for a long time. Before staining, it is often necessary to fix the albuminousbodies of the blood. To this end, different methods may be em-ployed. Immersion in absolute alcohol for from five to thirtyminutes, or in a mixture of equal parts of absolute alcohol andether for two hours, furnishes good results. There can be nodoubt, however, that the finest pictures are obtained when the speci-mens have been fixed by heat. For ordinary purposes it is onlynecessary to expose the air-dried blood films to a temperature offrom 100° to 120° C. for from one-half to two minutes, while in spe-cial cases a more prolonged exposure or a higher temperature maybe required. For fixing by heat, Ehrlich recommends the use of the Fig. Method of making blood smears. so-called Victor-Meyer apparatus in a slightly modified form. Thisis essentially a small copper kettle, covered with a thin plate, whichis perforated for the reception of the boiling tube. If a smallamount of toluol is boiled in this kettle for a few minutes, the cop-per plate is soon heated to a temperature of from 107° to 110° C, andretains this temperature sufficiently long for ordinary purposes. Inthe absenee of such an instrument, a small coal-oil stove, upon whicha copper plate measuring 10 by 40 cm. is placed, will answer thepurpose. Upon this plate the line corresponding to the desired tem-perature is ascertained by means of a series of drops of water, tol-uoI (boiling-point 110- to 112° C), xylol (boiling-point 137° to140° (,), etc., and noting the line at which ebullition occurs. Onceproperly replated, the
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Keywords: ., bookcentury1900, bookdecade1900, booksubjectdiagnos, bookyear1902
