Union of Soviet Socialist Republics (Continued) G/R.200 UPTAKE OF RADIOACTIVE STRONTIUM BY PLANTS AND ITS ACCUMULATION IN VARIOUS AGRICULTURAL CROPS Detailed analysis of Sr® uptake by plants in relation to their biological characteristic (plant species, vegetative period) and the properties of the soil. Both factors can influence to a large extent the incorporation of Sr® during the biological cycle. G/R.201 SOME RESULTS OF A STUDY OF THE BONE SYSTEM AFTER INJURY BY RADIOACTIVE STRONTIUM Reviews the experimental resuits obtained in the studies on the effect of boneseeking radioisotopes. The progressive pathological changes leading to the development of bone tumors are described. The disturbances in the osteogenetic processes during the initial stages after contamination are marked pretumorous changes; their histological characteristic and their pathogenetic significance are discussed. G/R.202 BLASTOMEGENIC EFFECTS OF STRONTIUM-90 Summarizes and evaluates the results so far published on the cancerogenic effect of Sr®*® in bone. In particular, the minimum and optimum tumor-producing doses, the latent period and the distribution of Sr®° are discussed. The connection between the blastomogenic effect and the development of leukemia is briefly mentioned. G/R.203 G/R.204 THE RADIATION HAZARDS OF EXPLOSIONS OF PURE HYDROGEN AND ORDINARY ATOMIC BOMBS Compares the hazards of the long-lived radioactive substances dispersed throughout the world after the explosion of a fission and a pure fusion bomb. Radiation doses to the gonads and bones are calculated and the number of persons affected (hereditary diseases and leukemia) then computed. The conclusion is drawn that a pure fusion bomb cannot be regarded as less dangerous to mankind than a fission bomb. pms TOWARDS AN ASSESSMENT OF THE HAZARD FROM RADIOACTIVE FALLOUT An attempt to assess the various forms of hazard involved in the contamination of the earth’s surface with long-lived radioactive fission products. The particular importance of Sr® is stressed. Effects of small doses of radiation and the concept of maximum permissible dose are discussed. G/R.205 NATURE OF THE INITIAL EFFECT OF RADIATION ON THE HEREDITARY STRUCTURES A survey of the present knowledge of the nature of the primary mechanisms through which ionizing radiation damages the hereditary structures. G/R.206 RADIATION AND HUMAN HEREDITARY Emphasizes the importance of the basic scientific principles of radiation genetics for the assessment of radiation-induced changes in human heredity. The natural mutation rate for various hereditary abnormalities is compared with the observations so far available on irradiated human population. The comparison of natural and induced mutagenesis both in experimental organisms and in men is the basis on which the doubling dose for man was estimated as approximately 10 r. The lack of exact knowledge and the urgent need for it is stressed. G/R.207 THE EFFECT OF RADIATION ON THE HISTOLOGICAL STRUCTURE OF MONKEY TESTES Presents the results of nistological analysis of monkey testes two years after exposure to a dose of 150-450 r. While the recovery process proceeds rapidly and is apparently complete in animals irradiated after the attainment of sexual F 193