Leucocytes in Normal Rhesus Monkeys

During a study of experimental measles in rhesus monkeys the available literature was consulted for the normal figures of total and differential white cell counts in these animals. It was found that the results reported by 11 different authors (table I) varied within a wide range. The differential count was always mentioned in percentages which either gives no idea of the absolute numbers, or can even present a wrong picture. In table III with a percentage of 43.8 the total number of lymphocytes is 7,670, and with a higher percentage of 52.7 the total number is actually reduced to 6,352. The present study was undertaken to find out the reason for these vastly different results reported by various authors. Twenty-two animals were examined daily for 4 to 12 days until a steady level was obtained. All the animals were apparently healthy, considering their daily temperature, body weight, activity, appetite arid stools. The counts were made at the same time daily before feeding. The animal was caught without being much excited and the blood was drawn when it was calm. Freely flowing. blood was drawn from a razor l)lade cut over the marginal