Takata and Murazugi (1941) reported significant increase in flocculation of blood serum two days after the passage of large groups of sunspots through the central meridian of the Sun.
Filk (1950) recorded fluctuations in the turbidity curves of the blood serum protein fractions that were correlated with the variations in solar activity.
The studies carried out by Shul'ts (1951) on the effect of solar activity on the blood system revealed that fluctuations in differential leukocyte counts were in phase with solar activity variations, and enabled the author to test the latter by the differential counts.
These tests were as follows: "A"—functional leukopenia, "B"—relative lymphocytosis, and "C" —total test of functional leukopenia and relative lymphocytosis. The last test was adopted in order to confirm Kassirskii's premise that functional leukopenia and relative lymphocytosis are pheno mena of the same order. This test proved to be the most sensitive indi cator of the evident influence of solar activity on the number of leukocytes in the peripheral blood.
Chemical tests are easier to analyze statistically since they are less affected by the factors influencing the leukocyte counts (age, state of health, nutrition, work, previous diseases, drugs, etc.), but the leukocytic tests proved to be as conclusive and valuable as Chizhevskii's index and Piccardi's chemical tests. The data at our disposal were collected in different regions of both hemispheres, from the equator to the poles. The total number of observations reaches several hundreds of thousands (more than 150,000 tests having been performed at the town of Sochi alone). Examinations were conducted by hematologists of the Sochi Branch of the All-Union Scientific Society of Laboratory Physicians, and by our asso ciates who often worked thousands of kilometers from Sochi.
Since the leukocytic tests of solar activity indicate the frequency of functional leukopenia and relative lymphocytosis in percentages, the actual Most observations were peformed on people in sanatoria, boarding houses, and rest homes located at different latitudinal and longitudinal sites in the USSR. Having established the pattern of fluctuations in the incidence of functional leukopenia and relative lymphocytosis in the Soviet subtropics and the Far North, the Baltic coast and the Pacific, and the Ukraine and Siberia, we decided to extend the range of our observations, and at present we have at our disposal data collected from laboratories of four continents.
The data received are of utmost scientific value owing to their scope as well as to their wide geographical distribution. These data formed the basis of our investigations, one section of which deals with the leukocytic tests of solar activity.
Blood samples were always taken under the same conditions: in the morning, on an empty stomach, and in a sitting position so as to exclude the effect of food intake, physical stress, change of posture, etc.
Although we strove to exclude all usual factors causing functional leukopenia or relative lymphocytosis, some of the investigated subjects might have had leukopenia and lymphcytosis as a result of some disease, drug, or other causes; however, they were too few to affect the results of our tests, since we excluded data obtained from hospitals and clinics, although people who are sick react to variations of solar radiation in the same way as-healthy people.
As an example, we reproduce the results obtained by our associate, N. L. Glushitskaya, which clearly show leukopenia to be synchronized with the corresponding sunspot number in tuberculosis patients during the current 11-year solar cycle (Figure 2).
The progressive decrease in the number of leukocytes accompanied with a relative lymphocytosis in the blood of healthy people has been reported recently. As a result, numerous articles have appeared in medical periodicals, proposing a revision of the existing norms both for practical purposes and for special work in scientific research institutes.
Such a downward trend from the norm was observed for the first time at the end of World War I, when the incidence of relative lymphocytosis and of functional leukopenia increased, although the latter was not as pronounced as it has been in recent years. This phenomenon was designated "war lymphocytosis" (Kriegslymphocytose) by Klineberger. In those years, 1917-1918, there was a maximum of solar activity, although the peak of the maximum was considerably lower than in the years 1957-1958, when the 11-year maximum coincided with the secular one.