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SCIENCE 



[N. S. Vol. XXVI. No. 673 



growth. So also the addition of the more 

 concentrated feeding stuffs, as cereals to 

 hay, straw, roots, etc., in the feeding of 

 domestic animals, was learned by simple 

 observation to be useful in the production 

 of milk, flesh, fat, work, etc., before science 

 had established the fact that the best re- 

 sults could be attained only by the proper 

 proportion in a ration of digestible protein, 

 fat, carbohydrates and ash. 



The history of nations, with the excep- 

 tion of one, shows, however, that these em- 

 pirical observations were not universally 

 put to practise by the tillers of the soil. 

 The capability of a rich virgin soil to pro- 

 duce remunerative crops for a generation 

 or more led to the baneful waste of most 

 fertilizing materials in the past. As a re- 

 sult of this practise the population of many 

 nations increased and civilization advanced 

 until the bountiful sources of plant food 

 contained in the soil became exhausted to 

 such an extent that an adequate amount 

 of food for the teeming populations could 

 no longer be produced, and retrogression 

 in every respect necessarily followed. 



The population of countries stands in a 

 direct relation to the food-supply, other 

 things being equal. AVhen the food supply 

 of the territory now occupied by our be- 

 loved country was limited to hunting and 

 fishing with a very insignificant amount of 

 agricultural crops, this vast domain could 

 support a population of only about three 

 millions of people. With the advent of the 

 white race and the gradual subjection of 

 the fertile soils to agricultural pursuits, 

 this territory now supports a population 

 of eighty millions of people and the limit 

 has not yet been reached. 



It is the province of agriculture to util- 

 ize a comparatively few, special, inorganic 

 forms of matter contained in the air and 

 soil and change them into organic com- 

 pounds, vegetable and animal, which may 

 serve as food and raiment for mankind. 



Since the transformation which matter 

 thus undergoes is of a purely chemical 

 nature, it stands to reason that the science 

 of chemistry was destined to free agricul- 

 ture from the slough of empiricism in which 

 it was engulfed and place it upon a sound, 

 scientific basis. The minds of many of the 

 most prominent chemists of the world were 

 imbued with the importance of study and 

 investigations leading to this end. As a 

 result of their labors truths were gradually 

 established and rational systems in the pro- 

 duction of vegetable and animal matter 

 based upon them were inaugurated. On 

 this occasion, therefore, it will only be pos- 

 sible to refer briefly to the more important 

 services which the science of chemistry 

 has done to increase and perpetuate the 

 food production of the world. 



About three quarters of a century ago 

 Liebig, who is generally regarded as the 

 father of agricultural chemistry, penned 

 the following words : 



A visible, gradual deterioration, of arable soils 

 of most civilized countries can not but command 

 the serious attention of all men who take an 

 interest in the public welfare. It is of the utmost 

 importance that we do not deceive ourselves re- 

 specting the danger indicated by these signs as 

 threatening the future of populations. An im- 

 pending evil is not evaded by denying its existence 

 or shutting our eyes to the signs of its approach. 

 It is our duty to examine and appreciate the signs. 



After this acute observer and far-seeing 

 philosopher had uttered these words and 

 published his first little book, entitled 

 "Chemistry in its Application to Agricul- 

 ture," which marks a new epoch in the 

 history of this important branch of human 

 industry, and Wiegeman and Polsdorf had 

 corroborated the theoretical views of the 

 great master by furnishing the infallible, 

 experimental proof, that the mineral or 

 ash constituents of plants were indispen- 

 sable to vegetable growth, the intelligent 

 farmers of Germany were eager to listen 

 to Liebig 's teaching and to profit by any 



