The blood, how to examine and diagnose its diseases.

  • Coles, Alfred Charles.
Date:
1898
Catalogue details

Licence: Public Domain Mark

Credit: The blood, how to examine and diagnose its diseases. Source: Wellcome Collection.

Provider: This material has been provided by The University of Leeds Library. The original may be consulted at The University of Leeds Library.

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    of the blood is somewhat more difficult in this position than when the finger is pricked. Slight hyperaemia may be produced before puncturing by gentle friction over the part, but the blood must not be squeezed out. The drop thus obtained is allowed at once to fall on the slide and the coverglass put over it, avoiding undue pressure; or we may touch the exuding drop with the covero-lass and then immediately place it upon the slide. The blood should be in as thin and uniform a layer as possible, the elements protected against any moisture or foreign matter in the form of dirt, and the process carried out as quickly as possible. If the specimen be rung round with oil or vaseline it will be protected from evaporation, and therefore remains longer unaltered.^ When the blood is to be examined for micro-organisms the place of puncture must be well washed with soap, then with i in looo Hg. perchloride, and, lasdy, with alcohol and ether. The needle should be sterilized by heat, and the slides and coverglasses scrupulously clean. Some observers maintain that the pressure of the coverglass is injurious, as it tends to unduly spread out the corpuscles, and adopt means by the intervention of a layer of paper, or drop of wax at the corners of the coverglass, to prevent this. This is, however, seldom necessary if ordinary care be taken.' The thinnest films are essential to the study of the nuclear structure of the leucocytes. Hayem uses a very thin ringed cell in order to follow any modifications of coagulation in inflammatory con- ditions. , 1 Specimens obtained in this simple manner show the size, shape, and colour of the red blood corpuscles,
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