Biochemical Studies on Marine Organisms

Our knowledge concerning the normal occurrence of zinc in animal tissues has been very limited until quite recently.The earlier investigators demonstrated that traces of zinc might be found in toxicological analyses in the absence of poisoning by this metal.Raoult and Breton (1877) reported four analyses of human livers in which the zinc content varied between 10 and 76 mg. per kilo.Lechartier and Bellamy (1877) made similar analyses, and in addition reported the presence of this metal in the muscle and liver of an ox, and in wheat, corn, barley, and other grains.The researches of Javillier (1908, a) established the widespread occurrence of zinc in the plant kingdom.More recently, the investigations of Weitzel (1914), Rost and Weitzel (1919), Delezenne (1919), and Rost (1920) have contributed toward a fuller appreciation of the significance of this problem.Birckner (1919) estimated the zinc content of a number of food products and, because of its constant, occurrence in the yolk of eggs as well as in cow's and human milk, he was led to infer that the element zinc exerts an important nutritive function.Marine animals are of especial interest in this respect.Bradley (1904) and Mendel and Bradley (1905) discovered zinc to be a normal constituent of the liver and the blood of the mollusks Sycotypus canaliculatus and Fulgar carica.Various other marine animals, including some of the most common mollusks and Crustaoea of the Long Island coast, were examined for zinc, but, with the exception of Urosalpinx cznerea, no appreciable amounts of the element could be found.Mendel and Bradley expressed their belief, however, that other marine forms may contain this