As could be expected, our findings provoked controversial views among Soviet epidemiologists and microbiologists. In this connection, a proponent of this work, the prominent Soviet doctor G. A. Ivashentsov wrote in 1931: "While technicians build rockets for interplanetary travel, physicians turn away even from phenomena that can be studied here on this planet." Continuing, and referring to the grippe, he wrote: "Studies of the grippe should release this problem from its present deadlock. In attempting to clarify the effect of factors already known (such as infection and social conditions) epidemiologists should collaborate in their work with meteoro logists and astronomers. In addition to the prevailing inertia in scientific medical thought, the passive attitude toward research of the practical significance of complex cosmic phenomena is based on the false concept of our helplessness in controlling their effects on us... However, the dark ages of superstitions, the slavish hopelessness that regards epidemics as a 'punishment from Heaven,' have vanished forever. Several epidemic diseases, closely linked with social conditions, have been eradicated under the socialist government; this urgent problem was clearly understood and successfully resolved. Its solution provides new possibilities for elucida ting and solving the following problems: utilization of the beneficial cosmic phenomena and neutralization of the injurious ones; and research of those which have not yet been studied or are regarded as incomprehensible or insurmountable. There is no doubt that proceeding along this path we shall solve several 'hopeless' problems in medicine, and particularly in epidemiology."* The afore-mentioned correlation between epidemics and solar activity has been gradually obscured by the progress in medical knowledge made toward the end of the last century, and reflected by the introduction of vaccinations and various preventive measures, especially social improve ments. Many agents of epidemics and pandemics which formerly took hundreds of thousands of human lives have been almost eradicated, with only infrequent outbreaks in their ancient foci. Consequently, epidemiological studies are only of historical and theoretical value; they demon strate the tremendous role of social reforms and of prevailing medical measures in the control of public health. Therefore, one must agree with the famous microbiologist, Academician S. N. Winogradsky, who mentioned in a letter to the author that, at present, cosmic agents can be ignored with respect to the onset and spread of epidemics, their role being negligible in comparison with that of biological agents. In a letter of 14November 1935, Winogradsky wrote: "Whenever the etiology is well known, the foci of infection can be suppressed and catastrophic epidemics prevented irrespective of solar activity." Summaries of the author's ex tensive research in this field have been published in two main monographs: in Moscow, in 1930 /19/, and in Paris, in 1938 /80/. However, in connec tion with several epidemic diseases (grippe, cerebrospinal meningitis, poliomyelitis, etc.) the effect of the solar factor still requires fundamental study. As grippe pandemics and certain other epidemics continue their periodic attacks on man, the opinion of Academician Winogradsky should be revised.
Periodic outbreaks of cholera epidemics are still being reported from certain countries in southern Asia. Epidemics of poliomyelitis are known to occur in the USA, France, and other countries. Therefore, an accurate prediction of outbreaks of several epidemic diseases is still highly desirable. Helioepidemiological studies are, for certain countries, an urgent medical necessity.
The question arises whether man or the bacterial cell conditions the coordinated development of solar phenomena and epidemics on Earth.
Referring to our work, Prof. Dubos /89/ assumed that the cellular growth and metabolic activity of several bacteria are affected by certain specific radiations which, in turn, depend upon the solar activity cycle.
In 1927 we began microbiological research after studying the spread of many epidemic diseases and of the synchronous variations in solar activity during past centuries, and publishing these data in the years 1924 and 1927-1929 /6, 13-16, 24, 27-29/, edited by Prof. N.A. Semashko (who personally contributed considerably to this work). It was shown that ordinary bacterial flora and certain pathogenic microorganisms react distinctly to specific solar phenomena, and this coincidence could be traced with an accuracy of up to 6 days. A few years later, under the direct influence of our work, the Kazan physician and microbiologist, S. T. Vel'khover, conducted a thorough microbiological study, lasting several years (1934-1942), of the effect of solar flares on the growth and meta chromasia of C or y n e b a c t e r i a; he confirmed by exhaustive investiga tion (over 85,000 observations) the existence of a strict correlation between the specific solar radiation and the physicochemical processes in micro organisms. He also demonstrated that these changes occur simultaneously in different places (in three independent laboratories) /86, 87/.
Studies of the microbiological data revealed that changes in the rate of metachromasia in C o r yn e b a c t e r i a started several hours, or even days before the solar phenomena were recorded instrumentally by the helio physicists. We suggested that when this occurred, C or y n e b a c t e r i a were reacting to phenomena developing in the deep layers of the Sun in accessible to the astrophysical instruments. The volutin of C or y n e b act e r i a is seemingly endowed with a high specific sensitivity to this type of radiation, and a method might possibly be elaborated whereby qualitative and quantitative changes in the Sun could be estimated by the chromaticity, or by colorimetric determinations of the volutin granules in C or yn e b a c t e r i a; in other words, heliophysicists must collaborate with microbiologists. Unfortunately our close collaboration with Vel'khover was terminated by his death in 1942. Claims of later authors to priority in this field of science are completely unfounded.
We explained this phenomenon— designated the Chizhevskii-Vel'khover effect— as the metachromatic response of certain microorganisms grown on well-defined media to Z-radiation emitted by the deep layers of the Sun that cannot be recorded astrophysically. This effect was discovered through extensive research which lasted almost 15 years, and required the isolation of a highly sensitive microorganism, a special medium for its cultivation, and the examination of many thousands of preparations. Astro physicists disagree on the depth at which generation of solar phenomena responsible for Z-radiation occurs. In 1940 the author succeeded in fore casting the appearance of the solar radiations with the aid of live bacteria.
Not only N. A. Semashko, G. A. Ivashentsov, and S. T. Ve1'khover, but many other eminent scientists supported our viewpoint and showed interest in our investigations, rather than regarding them as "fantastic hypotheses." Scientists were already aware at the time that statistical principles were quite as sound as laboratory experiments. Among them were Academicians V. I. Vernadskii, D. K. Zabolotnyi, P. P. Lazarev, K. E. Tsiolkovskii, A. V. Leontovich, V. Ya. Danilevskii, Associate Member of the Academy of Sciences of the USSR Prof. G. D. Belonovskii, Prof. A. V. Reprev, A. A. Sadov, and others, who supported our research verbally or in print.