The super-scientific exploitation of the potato would extend far-reaching benefits in every direction. Not only would considerable stretches of derelict agricultural Britain be brought into productivity, but the very stimulation of the poor soils would bring about startling expansion in the production of artificial fertilizers, and would tend to stabilize such industries. In this way the recovery of waste in many other directions would be fostered--potash from the flues of the blast furnaces; basic slag from the dumps disfiguring the countryside in the vicinity of our ironworks; sulphate of ammonia from our gas and coking ovens; nitrates from the air. These would offer scope for employment, and tend to keep money within the confines of these islands, because the expansion of waste-recovery plants upon a sufficiently impressive scale in the interests of agriculture, with the local demand constituting the backbone of the trade, would encourage production for export. The labour thus absorbed would more than counter-balance the displacement experienced on the farms, and would redound to the benefit of the latter, because foods for poor and rich soils would be turned out in increasing streams and at lower prices. Thus it will be seen that any development of the potato, along modern scientific lines, and in such a way as to frustrate waste, must represent a big stride forward in the progressive cycle. CHAPTER XII CONVERTING NITROGENOUS REFUSE INTO SOAP A startling corollary of contemporary economic conditions is the spirited struggle which is now being waged between the table and the bath. The structural fabric of the human body demands a certain proportion of fat to ensure its smooth rhythmic working in precisely the same way as a machine requires oil. At the same time a cleanser is necessary wherewith to scour the external surface of the body to obtain protection against the ravages of disease. Fat is essential to fulfil this mission also. But there is an insufficient supply forthcoming to meet the complete claims of both. So the question arises--Which shall be satisfied? Little Mary or Mother Hygeia? When Mégè Mouries, animated by the contention that it was preferable for the poor of Paris to be able to obtain a first-class nutritive butter substitute in preference to butter of doubtful quality, advanced his discovery of margarine as the solution to this problem, he little realized what a tremendous upheaval his invention was destined to achieve, or the staggering problem it would ultimately present to civilization. Certainly for many years his butter substitute, contrived from animal fat and milk, was regarded askance by the community in general. It was grudgingly conceded to be a possible food only for the poorest of the poor--those denied the opportunity from lack of means to purchase butter of any description.