Methods of morbid histology and clinical pathology / by I. Walker Hall and G. Herxheimer.

  • Hall, I. Walker (Isaac Walker), 1868-
Date:
1905
Catalogue details

Licence: In copyright

Credit: Methods of morbid histology and clinical pathology / by I. Walker Hall and G. Herxheimer. Source: Wellcome Collection.

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    latter with a piece of soft wash-leather; in the same manner the oil may he removed from the cover-glass, or xylol may be added and the xylol and oil blown off by means of a capillary glass tube. If the oil has dried on the immersion lens, then it should be taken away with a drop of alcohol or a drop of chloroform, benzene, or xylol; the last reagent may be used for Canada balsam, but in this case the procedures must be rapidly carried out, so that the balsam which holds the lenses together is not thereby loosened. Should spots be observed while examining the preparation, it can be easily determined by moving the oculars whether the speck is on the oculars, or by moving the preparation itself, whether the spot is on the slide or on the objective. Specimens should be always first examined with the low power of the microscope in order to obtain a general impression, and then certain areas may be studied under the higher powers, their relations to surrounding structures being previously determined. The beginner will be often surprised to note how much an experienced worker uses the low-power objective, and how many details he is able to thus recognise. The former may be advised, when he has examined a part of the preparation with the high power, to again examine it with the low power. By such means he will learn to recognise details which the high power alone revealed to him before. Also appertaining to a microscope, but only used for special purposes, are :— I. A movable stage, which may be temporarily or permanently fixed. Although its general use is not advisable, since the preparation can be better controlled by hand, it is nevertheless valuable for thorough detailed examina- tions of the specimen for certain details and for enumeration of blood corpuscles, etc. II. An ocular micrometer. This is a circular piece of glass which is placed in the ocular and upon which measured divisions are scratched. III. A warm stage for the observation of living objects. Recently a simple electrical apparatus has been devised by Ross. It consists of a small disc of ebonite with a square gap in the centre for the cover-slip and objective of the microscope, and contains a coil of wire which, when con- nected with an electric light circuit, gives out heat sufficient to raise and maintain the temperature of the centre of the slide at 37° C. It can be slipped on and off the slide without altering the focus, and requires no attention.1 i Sold by Drake and Gorham, 66 Victoria Street, London, W.