Oxygen

(oks'-ij-en). O 15.96; quantivalence II. One of the elements. See Elements, Table of. It is a colorle , tastele , odorle gas, constituting one-fifth of the atmosphere, eight-ninths of water, three-fourths of organized bodies, and about one-half the crust of the globe. I: is characterized by its affinity for the other elements, with every one of which it unites, excepting fluorin. It is an active element in the oxy-acids, and in all the alkaline hydrates. In organic chemistry it unites with radicles and forms alcohols, ethers, and their derivatives. Oxygen is inhaled as a therapeutic agent in diseases of the respiratory organs and blood. It is e ential to respiration; its combination with the ti ues yields heat and other energy. Combustion is also dependent upon it, consisting of a rapid oxidation, with the evolution of heat and light. It exists also in an allotropic form known as ozone.