Physiology and Hygiene for Secondary Schools by Francis M. Walters;A.M.
page 45 of 527 (08%)
page 45 of 527 (08%)
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hand from the knuckle down to the first joint. Bend this joint and give it
a sharp prick with the point of a sterilized âneedle just above the root of the nail. Pressure applied to the under side of the finger will force plenty of blood through a very small opening. (To prevent any possibility of blood poisoning the needle should be sterilized. This may be done by dipping it in alcohol or by holding it for an instant in a hot flame. It is well also to wash the finger with soap and water, or with alcohol, before the operation.) Place a small drop of the blood in the middle of a glass slide, protect the same with a cover glass, and examine with a compound microscope. At least two specimens should be examined, one of which should be diluted with a little saliva or a physiological salt solution.(16) In the diluted specimen the red corpuscles appear as amber-colored, circular, disk-shaped bodies. In the undiluted specimen they show a decided tendency to arrange themselves in rows, resembling rows of coins. (Singly, the corpuscles do not appear red when highly magnified.) A few white corpuscles may generally be found among the red ones in the undiluted specimen. These become separated by the formation of the red corpuscles into rows. They are easily recognized by their larger size and by their silvery appearance, due to the light shining through them. *To examine White Corpuscles.*âObtain from the butcher a small piece of the neck sweetbread of a calf. Press it between the fingers to squeeze out a whitish, semi-liquid substance. Dilute with physiological salt solution on a glass slide and examine with a compound microscope. Numerous white corpuscles of different kinds and sizes will be found. Make sketches. *To prepare Models of Red Corpuscles.*âSeveral models of red corpuscles should be prepared for the use of the class. Clay and putty may be pressed |
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