In 1897 Buchner submitted yeast to great pressure, and isolated a nitrogenous substance, enzymic in character, which he termed "zymase."
Thus, then, alike for maintenance, for increase, and for the exercise of force, the exigencies of the system are characterized more by the demand for the digestible nonnitrogenous or more specially respiratory and fat-forming constituents than by that for the nitrogenous or more specially flesh-forming ones.
Similarly soils with less than i% of nitrogen are likely to be benefited by applications of nitrogenous manures.
Thus Nepenthes secures a supply of nitrogenous food from the animal world in a manner somewhat similar to that adopted by the British sundew, butterwort, and other insectivorous plants.
Of mineral constituents, whether used alone or in mixture with nitrogenous manures, phosphates are much more effective than mixtures of salts of potash, soda and magnesia.