The blood platelets in rats on adequate and inadequate diets.

Abstract

In view of the fact that Bedson and Zilva 1 disagree with Cramer, Drew and Mottram 2 on the behavior of the blood-platelets in rats deficient in vitamin-A, it was found desirable, in the course of the study of the pathology of avitaminosis, to investigate this disputed question. Applying a method for platelet counting which has for its basic principles the minimum of manipulation and the absence of contact of the drawn blood with possible coagulant surfaces, we have found the blood-platelet content in normal albino rats on adequate diets to approximate 400,000 to 600,000 per cu. mm. We have not observed any significant variation from this average in rats subsisting on diets lacking vitamin-A and showing the typical symptoms of such a deficiency. These observations are essentially different from those of all the above mentioned workers in regard to the normal platelet content of white rats, and confirm Bedson and Zilva's contention that the platelet content is not affected by diets deficient in vitamin-A. The method employed, suggested by Dr. A. B. Dayton's practice on man, is as follows: after the freely protruding tail of the encaged rat is washed, if necessary, with water and dried, a portion of its surface is painted with the diluent and allowed to dry. One of the superficial veins in that area is then punctured with a sharp lancet on which the diluent has also been dried, and as the Mood wells up freely it is drawn up into an erythrocyte pipette, the stem of which had previously been filled with the diluent to the 0.5 mark, until the diluent column reaches the 1.0 mark. The diluent is then added to the 101 mark, giving the usual 1 :ZOO dilution.