TRAN3ACTI0JIS OF SECTION B. 515 



amount of living matter, wbich in the body loses the condition of life, is, in equal 

 temperatures, directly proportional to the mechanical eilects produced in a given 

 time. The amount of tissue metamorphosed in a given time may be measured by 

 the quantity of nitrogen in the urine. The sum of the mechanical eftects produced 

 iu tw(i individuals, in the same temperature, is proportional to the amount of nitro- 

 gen in their urine, whether the mechanical force has been employed in the voluntary 

 or involuntary motions, whether it has been consumed by the limbs, or by the heart 

 and other viscera.' 



Thus, apparently influenced by the physiological considerations which have been 

 adduced, and notwithstanding in some passages he seemed to recognise a connection 

 between the total quautity of oxygen inspired and consumed and the quantity of 

 mechanical force developed, Liebig nevertheless very prominently insisted that the 

 amount of muscular tissue transformed — the amount of nitrogenous substance oxi- 

 dated — was the measure of the force generated. He accordingly distinctly draws 

 the conclusion that the requirement for the azotised constituents of food will be in- 

 creased in proportion to the increase in the amount of force expended. 



It will be obvious that the question whether in the feeding of animals for the 

 exercise of mechanical force — that is, for their labour — the demands of the system 

 will be proportionally the greater for an increased supply of the nitrogenous or of 

 the non-nitrogenous constituents of food, is one of considerable interest and prac- 

 tical importance. To this point I shall have to refer further on. 



So far, I have endeav'oured to convey some idea of the state of knowledge on the 

 subject of the chemistry of agriculture prior to the appearance of Liebig's first two 

 works bearing upon it, and also briefly to smnmarise the views he then enunciated 

 in regard to some points of chief importance. Let us next try to ascertain some- 

 thing of the influence of his teaching. 



Confining attention to agricultural research, it may be observed that in 1843 — 

 that is, very soon after the appearance of the works in question — the Roj^al Agri- 

 cultural Society of England first appointed a consulting chemist. .Vt that date 

 Dr. Lyon Playfair was elected ; m 1848, Professor AVay ; and in 1858 Dr. Voelcker, 

 who continues to hold the office with much advantage to that union of ^Practice 

 xcith Science. ' which the Society by its motto recognises as so essential to progress 

 Also in 1843 there was established the Chemico-Agricultural Society of Scotland, 

 which was, I believe, broken up, after it had existed between four and five years, 

 because its able chemist, the late Professor Johnston, failed to find a remedy for the 

 potato disease. In 1845, the (Jhemico- Agricultural Society of Ulster was estab- 

 lished, and appointed as its chemist. Professor Hodges, who still ably performs 

 the duties of the office. Lastly, the very numerous ' Af/rtcidtural Experimental 

 Stations ' which have been established, uot only in Germany, but in most Conti- 

 nental States, owe their origin directly to the writings, the teachings, and the 

 influence of Liebig. The movement seems to have originated in Saxony, where 

 Stockliardt had already stimulated interest in the subject by his lectures and his 

 writings. After some correspondence, in 1850-1, between the late Dr. Crucius 

 and others on the one side, and the Government on the other, the first so-called 

 Af/riculfural Exjierimental Station was established at Mochern, near Leipzig, m 

 1851-2. In 1877, the twenty-fifth anniversary of the foundation of that institu- 

 tion was celebrated at Leipzig, when an account (which has .since been published) 

 was given of the number of stations then existin?, of the number of chemists engaged, 

 and of the subjects which had been in\'estigated. From that statistical statement 

 we learn that in 1877 the number of stations was : — 



In the various German States , , , 74 



In Austria 16 



In Italy 10 



In Sweden 7 



In Denmark 1 



In Russia ....... 3 



In Belgium ....... 3 



In Holland . 



L L 2 



