Surgery / by John Allan Wyeth.

  • Wyeth, John A. (John Allan), 1845-1922.
Date:
1908
Catalogue details

Licence: Public Domain Mark

Credit: Surgery / by John Allan Wyeth. Source: Wellcome Collection.

Provider: This material has been provided by the Augustus C. Long Health Sciences Library at Columbia University and Columbia University Libraries/Information Services, through the Medical Heritage Library. The original may be consulted at the the Augustus C. Long Health Sciences Library at Columbia University and Columbia University.

    797/832 (page 785)
    CHAPTER XXXIX THE BLOOD HcematoJogy.—A careful study of the blood, especially as to the percentage of hEemoglobin which is present, and the condition of tlie various eorjmscular elements and their numerical proportion to each other, is of imjjortance in the treatment of many surgical lesions, and should enable the surgeon to detect not only any form of ansmia, but to determine whether it is a tj^pe of blood impoverishment which can be corrected, or whether it is of the graver or more pernicious forms which would either preclude an operation or, if this is absolutely necessary, would enable him to announce the gravity of the prognosis. In ordinary practice it is not always essential to differentiate between a per- nicious anjemia or a leulca?mia, or whether tliis latter condition is present in the l}Tnp]iatic or splenic-myelogenous form, for the reason that all of these graver varieties call a halt to operative measures when these may be avoided. But the ansemia which comes from malnutrition or malaria or chlorosis can be positively diagnosticated by a careful blood technic. In general, the resistance of the tissues may be measured by the nearness of the hfemoglobin ratio to the normal. Normal blood contains approximately 13..5 of haemoglobin, but for convenience the normal amount is reckoned at 100 per cent. A simple method of determining this proportion is by means of the Tallquist hsemoglobin scale, which is suiSciently accurate for ordinary purposes, and has the advantage of being made quickly and without artificial light. It consists of sheets of absorbent paper which, when stained with a drop of blood, the redness or riclmess of the stain is determined by comparison with a fixed scale of colors. A low percentage of hajmoglobin contra-indicates the shock or exhaustion of an antestlietic and an operation. It suggests the aid of the microscope in a further examination as to the condition of the corpuscular elements of the blood. It is advised by Mikulicz never to operate wlien the register of the hsemometer shows less than 35, and it would 2}robably be safer to ptlace the standard 10 or 15 points higher.^ Under the microscope there are observed the red corpuscles (erytlirocytes), the white corpuscles (leucocji:es), and the blood platelets. ' A more accurate method is that employed with von Fleischl's haemometer, which consists of a metal stand resembling the stage, pillar, and base of a microscope. In the center of the stage is a circular opening, which receives a circular cell or tube with a glass bottom and which is divided into two equal compartments by a partition. Beneath the stage is a plaster-of-Paris disk, not unlike the mirror of a microscope both as regards its shape and position. In a sliding groove beneath the stage a metal frame is iitted, which supports a colored glass prism, wedge-shaped and accordingly deeper in color at one end than at the other. By means of a milled screw the prism can be moved back and forth, and at will any portion of its length can be brought into view through the opening in the stage. When the cell is in its place on the stage, the prism can be seen through one of its compartments, while the white surface of the plaster disk is seen through the other. For use, both these compartments are filled with water, and to that compartment which appears white a certain measured quantity of blood is added and thoroughly mixed with the water. If the room is now darkened and a candle is placed in front of the apparatus and the glass prism moved back and forth, there wiU be a time when both compartments will appear to have the same color. A reading taken from the scale on the back of the stage, when both compartments are aUke, expresses the percentage of hEemoglobin. The blood is measured by means of small capillary pipettes fixed in metal handles. These are so small that if they are thoroughly clean they will immediately become filled by capillary attraction if one end is touched to a drop of blood, obtained in the usual way. Three or four of