As civilization developed, man passed through the Stone Age, the Iron Age, and the Bronze Age. Now we are living in the Plastics Age.As supplies of iron, copper, lead, and other metals decrease, they are replaced mostly by plastics. The conquest of space and Mount Everest, the rapid development of industry, and the higher standard of hygiene and clothing would not have been possible without the development of the plastics industry.Plastics are obtained from salt, petroleum, wood, methane, gas, quartz, etc. Because our country possessed these raw materials, the plastics industry was developed and large plants were built.Simultaneously with the development of the plastics industry, studies for observing the health status of workers exposed to the new chemicals were initiated. There has been a rapid increase in the number of chemicals used, and we do not yet know all the adverse effects of these new chemicals. Some substances cause diseases in man which cannot be reproduced in animals, such as, arterial hypertension, Raynaud's phenomenon, scleroderma, and gastricduodenal ulcer, and unfortunately, when animals are exposed to toxic substances, they cannot describe the onset and evolution of the disease.Plastics, as finished articles, are considered generally harmless. The problem is, to what extent do the monomers or substances used in the chemical industry determine acute or chronic effects in the human organism.

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After establishing acute toxicity of vinyl chloride, we considered it necessary to carry out a 3 months chronic experiment to see the effects of long-term exposure on animals. We also tried to show the effect of vitamin C on poisoned animals. METHOD OF WORKThe experiment was carried out on 6 groups of 10 guinea pigs each, the animals having about the same age and weight. The guinea pigs were kept under laboratory conditions for 2 weeks, to allow them to accommodate to the environment. The toxic effects were observed on animals with normal feeding and also on other groups fed with an excess of vitamin C . We also wanted to estimate the restoration capacity of animals by interrupting the poisoning. The guinea pigs were exposed to a 10 percent vinyl chloride concentration for 2 h daily, in a gassing chamber of 580 liters. The air was kept in constant motion for a good homogenization of the poison.The first group served as controls and was fed normally.The second group was fed in the same way as the first, but was exposed daily to 10 percent vinyl chloride for 90 days, and then sacrificed.Groups 111, IV, V, and VI were fed normally and 10 mg of vitamin C , in a solution of 20 percent sepharose, was administered orally with a pipette, during 90 days.In these groups, the exposure to poisoning was differentiated. Group 111 was exposed for only 1 month, then kept for 2 months without poisoning, and at the end of the 90 days period the animals were sacrificed. Group IV was exposed for 2 months, not exposed for 1 month, and then sacrificed. Group V was exposed for 3 months to vinyl chloride and sacrificed, and group VI served as a contra1 for groups I11 and V which were exposed but received a supplement of vitamin C .During the experiments the animals were checked monthly for: growth, hematological changes, spontaneous motility, and ascorbinemia. At the end of the 90 days period, specimens were taken for histopathological and histochemical examinations. RESULTSGrowth of animals differs according to the duration of poisoning and vitamin uptake. The guinea pigs from group I1 having 3 months poisoning, without surplus of vitamin C had the slowest growth, as compared with group I, controls, the difference being statistically significant (p < 0.01). The other groups, which had been poisoned and had a surplus of vitamin C behaved as follows. Group V although poisoned for 3 months had a better growth than group 11; but without sig-159

During the production of polyvinyl chloride, vinyl chloride vapor and gas escapes occur, which have a toxic effect upon the workers. The toxic effects of gases resulting from the pyrolysis of polyvinyl chloride are also well known.Patty' in 1930 stated that a 3-min exposure at 2.5 percent vinyl chloride produced dizziness and disorientation in humans. Lester et aL2 reported that 3 men and 3 women exposed for 5 min at concentrations of 0-2 percent had no symptoms.The chronic action of vinyl chloride in men was studied in the Clinic of Occupational Diseases of Gorki by A. I. Plesitzer, E. M. Bongard, and N. A. Smironva, as cited by Filatova et al? They observed the presence of angioneurosis in exposed men. Filatova et al.8 also mentioned the presence of angioneurosis in men working in vinyl chloride production. The vinyl chloride concentration in the working places was between 9-750 mg/cu.m. also observed angioneuroses, hepatomegaly, enzymatic changes, and other symptoms in workers. Cgpusan and Sucid found dermatosis and scleroderma in workers engaged in the production of polyvinyl chloride. Pzslaru and Ungureanu" found in the same workers functional modifications of the cardiovascular system. Gabor et al. ' found liver disturbances in the same plant by means of biochemical analysis. The vinyl chloride concentration in 1964 varied between 200-300 mg/cu.m. Today these concentrations are below this level.