V. The nitrifying process and its specific ferment.—Part I

The spontaneous oxidation of nitrogen in nature is a process which has long attracted attention in consequence of the great practical importance of the products to which it gives rise. Indeed, so great is the demand for potassium nitrate, nitre, or saltpetre, the principal derivative of the oxidised nitrogen, that the process of nitrification is often artificially stimulated by placing nitrogen, in the form of refuse animal matter, under the most favourable conditions for undergoing this change. The process of nitrification has thus been carried on for ages as a regular industry in India, and even in some European countries, thus especially in France during the Great Blockade. For a number of years past, however, the principal source of nitric acid and its derivatives has been the enormous deposits of nitrate of soda occurring in South America, which deposits themselves may, however, possibly be the product of a vast nitrification-process in a former period of the Earth’s history. But although nitrification had thus been practically studied for centuries, it was only in 1878 that the process was shown by Schlcesing and Muntz (‘Cornpt. Bend.,’ vol. 84, p. 301; 85, p. 1018) to be a fermentation change, and entirely dependent upon the presence of certain minute forms of life or micro-organisms. But although this connection was thus first experimentally demonstrated in 1878, it had with characteristic foresight been already surmised by Pasteur in 1862.