SIR WILLIAM CROOKES'S disturbing pronouncement, made in 1898, on the subject of the approaching failure of the world supply of wheat for lack of combined nitrogen, lives in the memory of many “Are we to go hungry and to know the trial of scarcity?” he asked, and added, “those present who may a trend the meeting of the British Association Thirty years hence will judge how far my forecasts are justified.” Naturally, a negative answer to his question was given at the British Association meeting last year, but had he said “sixty years hence,” no one would have dared to give a confident reply. On the other hand, his prophecy in regard to the manufacture of combined nitrogen has come true. Led by Germany, nearly every civilised country in the world is actively producing synthetic fertilisers. Now, it should be noted that Crookes confined his attention to the need for nitrogen in the production of wheat. Recent events in the agricultural world, however, justify some consideration being given to a wider aspect of the nitrogen problem; for, as a recent writer has said, the sum total of life upon this planet is limited by the amount of available nitrogen in combination; important as wheat is in human dietetics, the supply of meat is equally vital. The farmer everywhere is in fact engaged in the manufacture and marketing of combined nitrogen in one form or another. He buys nitrogen in the form of manures and feeding stuffs, and markets it again as corn, meat, or milk. He makes nitrogen when he sows clover and other leguminous plants; and he conserves it for future use when he lays his land down in grass.