Turkish Thrace, Spring 1966. Veterinarians from Kirklareli province, most eastern of the five that make up European Turkish Thrace, vaccinate sheep against foot and mouth disease. Since 1962 Europe has been threatened with invasion by African and Near Eastern forms of foot-and-mouth disease. None of the continent's 375 million cattle, pigs, buffaloes, sheep and goats has immunity to these non-European forms of the dreaded disease and should either break through it would cost millions in livestock losses. So far these invading forms have been checked in buffer zones set up in Thrace by the Food and Agriculture Organization and the Bulgarian, Greek and Turkish governments. But the danger of a breakthrough is still there and the fight goes on.