Trichinosis Control in Copenhagen

Extract

During a recent visit to Copenhagen, through the courtesy of Dr. Bahr and of the Chief Veterinary Superintendent, I visited the Central Meat Market. Veterinary inspection of all living animals sent to the market is exercised, as well as of all carcases. If a carcase appears the least abnormal, without definite macroscopic changes, it is examined bacteriologically in an attached laboratory, equipped and staffed for the purpose, and all carcases of pigs, as well as any imported swine products, e.g., American hams, are subjected to examination for trichinosis. For this purpose, three small pieces of tissue are taken from every carcase or ham. From each piece of tissue six specimens are prepared for microscopical examination, so that eighteen microscopical specimens in all of every carcase, or other swine product, are subjected to examination. For the examination a “compressorium” is made use of, consisting of two rectangular pieces of plate glass, measuring about 6 in. × 2½ in., which are clamped together by a threaded bolt with nut at either end. One plate is divided into eighteen numbered squares, six squares longitudinally by three squares transversely. Particles of tissue about the size of a rice grain or so, with a drop of saline solution, are each placed in a square, so that the precise derivation of the material in each square may be recorded by its number. When all the squares have been filled, the corresponding plate is applied and screwed up, so as to squeeze out the tissue into a layer thin enough for microscopical examination with a low power, and in area about the size of a shilling. So far, there is nothing novel in the method, which has been practised for years, e.g., at Hamburg. But at Copenhagen, instead of direct microscopical examination of the specimen, an image of it is projected on to a screen, and is viewed thereon with the naked eye. One assistant can examine 100 specimens a day.