MATERIAL BESOUBGES OF LIFE. 345 



Thcproportionof phosphates in thecrust of the earth below organicreraains 

 is very slight, insufficient for the support of the higher forms of vegetable or 

 animal life. It has been concentrated and gathered into the soil by the 

 selective agency of the organic world, as it continues to be concentrated 

 from the soil by each individual plant, and from vegetable products by each 

 individual animal. Nearly all the phosphorus accessible on the planet has 

 been the constituent of living bodies. Its proportion in the soil is a main 

 factor in the growth of cereal grains. Already, and with the stretch of land 

 to the westward, bone-earth and phosphatic guanos are well known in 

 American markets. When phosphates fail at the root of the plant, grain 

 fails at the mill; and when, from waste at the mill, phosphates fail in the 

 bread, the bones and the teeth fail in growing bodies. The improvidence 

 that leaves excretory phosphates to be washed away to the salt sea, farther 

 from the reach of life than they were in the primitive rocks, is an improvi- 

 dence that prepares an inheritance of poverty for after-generations. And 

 the ruthlessness that permits the purveyors of food to sift phosphates from 

 the food of men does its part to enfeeble the present generation. 



There remains to notice another representative of the adequate resources, 

 potassium. The statements made as to the supply of phosphorus, with some 

 resei'vation, become true for potassium. Certain of the rocks contain a pro- 

 portion of it, but from insolubility this is slowly available,. and is insufficient 

 for the needs of higher organic life. The soils contain more, because the 

 organic world has gleaned for the soil. Potassa and soda are two alkalies 

 which replace each other in the laboratory at the convenience of the chem- 

 ist, but, in the choosing of the living cell, one of these is always taken and 

 the other left. We get potassa free from soda in the ash of a tree which 

 grew in a soil having more soda than potassa. From sea-water, containing 

 near 200 parts of soda to one of potassa, the sea-weeds furnish an ash having 

 two to twenty times more potassa than soda. From the blood of man, having 

 ten to fifteen times more soda than potassa, the muscles obtain a composition 

 of sis or seven times more potassa than soda. 



This gleaning is good proof of the value of more, and the evidence is con- 

 firmed by the aj)plication of potassa as a fertilizer. The stock of potassa — 

 which is used somewhat in she arts—is derived mainly from the gatherings 

 of the organic world. The ash-wagon takes up the savings of. the hearth. 

 In France the washings of sheep's-wool are saved, and 160 j)ounds of good 

 potassium carbonate are obtained from a ton of the wool. In the pioneer 

 life of this countr}^, the housewives have burned corn-cobs and taken the ash 

 for baking-powder, eighty per cent, potassium carbonate, and preferable to 

 the "dietetic saleratus" now used. Should the ash of the entire corn-crops 

 of the United States be taken without loss, it is estimated that over 100,000,- 

 000 pounds of potassium carbonate would be obtained. In the salt-beds of 

 Stassfurt, Germany, there is a good proportion of potassa, and the use of 

 this supply has been ste»adily increasing, both as material in manufactures 

 and as a fertilizer. 



