A guide to the clinical examination of the blood for diagnostic purposes / by Richard C. Cabot.

  • Cabot, Richard C. (Richard Clarke), 1868-1939.
Date:
1901
Catalogue details

Licence: Public Domain Mark

Credit: A guide to the clinical examination of the blood for diagnostic purposes / by Richard C. Cabot. Source: Wellcome Collection.

    39/552 (page 13)
    Counting the Red Corpuscles. (a) After puncturing the ear as above described, and as soon as the blood is flowing freely, put the point of the “ red counter ” into the drop as it emerges from the ear, and by sucking gently on the rubber tube attached to the other end, draw up blood to the mark 0.5 on the pipette. It is convenient to rest the end of the pipette on the thumb as shown in Fig. 3. It needs some practice to stop exactly at the mark, but if we hap¬ pen to draw the blood up a little past the mark 0.5 no considerable error results, pro¬ vided we draw the column down again to the mark by tapping the point of the pipette on a towel, and provided also that the in¬ strument is perfectly clean and dry. The aim and intention, however, should always fig. 3— Method of Resting Point be to stop exactly at the mark 0.5, and with of Pipette on the Thumb while . . Sucking in Blood. a little practice we can do it, except with nervous or delirious patients, and those who carelessly move the head just at the critical moment. With such patients we usually have to content ourselves with drawing the blood a little beyond the mark 0.5 and then drawing it down again to the mark as above described. Diluting the Blood. (b) The bottle of solution to be used for diluting the blood should be ready uncorked at the bedside. Of the many solutions suggested by various authors none is better than Gower’s, the for¬ mula for which is as follows: Sodii sulphat. gr. 112 Acid, acet. 3 v. Aquae. § iv. Toisson’s solution is also very useful and stains the white cor¬ puscles so that they can be easily distinguished from the red. Its. composition is as follows: Methyl violet, 5 B. 0.025 gm. Sod. chlor. 1.000 “ Sod. sulpli. 8.000 “ Neutral glycerin. 30.000 cm. Aquae destill. 160.000 “