ON THK VITALISTIC VIKW UF NATURK. 391 



of very valuable but unconnected researches in all the 

 (litlerent countries where chemistry was cultivated. 

 Priestley, in England, hiul noticed ilu' purifying effect 

 of plants on air ; De Saussure, in a series of remarkable 

 experiments, carried on in the last years of the eighteenth 

 century at Geneva, established the fact that in sunlight 

 plants increase the quantity of cailnm and other con- 

 stituents in their tissues. Ingenhousz in Holland and 

 Senebier in France had shown that in the presence of 

 sunlight bubbles of oxygen gas are given off by plants 

 when plunged under water, and had traced this oxygen 

 to its source, the carbonic acid in the atmosphere. Sir 

 Humphry Davy had applied chemistry to agriculture ; 

 and, much later, (Jerman physiologists like Tiedemann 

 and Johannes ^Midler had recognised the necessity of 

 explaining the processes in the living body chemically. 

 All these labours, however, were detached, and their 

 value was little known. It was therefore a very timely 

 proposal which issued from the British Association in 

 1839, that a report on the present state of organic 

 chemistry should 1)6 drawn up. For this task no less 

 a person than Justus Liebig was selected.^ The event 



1 The sources of information on 

 Liebig'.^ great work in revolutionis- 

 ing the science of life tViiough his 

 application of organic chemistry to 

 agriculture and i>hysiology are nu- 

 merous. In particular there are 

 two aclilresses by Vogel and von 

 Bischoff, delivered in the Munich 

 Academy in 1874, Hof mann's " Fara- 

 dav" lecture, delivered in the Royal 



Liebig, his Life and Work." Bis- 

 ohofTs address contains a very full 

 discussion of Liebig's vitalistic sym- 

 ])athies. His great influence was 

 established as much by his sjjecial 

 scientific discoveries as by his 

 method of teaching, — by his early 

 attempts to popularise science and 

 make it an educational power 

 through his well-known ' Familiar 



Institution in 187.'>, and a very j Letters.' He was in this respect a 



able sunnnary, drawn mainly from i pioneer, as aftei- liiin Hehuholtz and 



these sources by Mr W. A. Shen- [ Du Bois-Reyniond were pioneers in 



stone, in Cassell's 'Century Science' spreading scientific ideas by means 



Series (189:")), entitled ".Justus von of ]inpular lectures and addresses. 



