Joseph Reynolds Green. 



xxxvn 



affects either the formation or the activity of thrombin (" On Certain Points 

 connected with the Coagulation of the Blood," ' Journ. Physiol.,' 1887). wtf 



Green did not at once decide between the two sciences, which seemed 

 to have equal attractions for him. His appointment in 1885 by Sir Michael 

 Foster as Demonstrator in Animal Physiology, a position that he held 

 with great credit for two years, determined the nature of his work for 

 the time. But even so he continued to pursue more or less botanical 

 research, the results of which were published in two papers read before the 

 Koyal Society ; the one on the protein constituents of latex ('Proc. Eoy. Soc.,' 

 1886 ) ; the other, of greater importance, on the changes in the proteins of the 

 seed which accompany germination (' Phil. Trans.,' 1887 ) in which he con- 

 firmed for the Lupin the discovery by von Gorup-Besanez (1874) of a proteo- 

 clastic enzyme in the seed of the Vetch, and amplified it by showing that the 

 protease is tryptic in its action. These papers indicated the direction of his 

 future work. 



In 1887 Green was appointed Professor of Botany to the Pharmaceutical 

 Society of Great Britain, and consequently he devoted himself wholly to 

 that science. During the 20 years that he held this office his literary output 

 was voluminous. The first 12 volumes of the ' Annals of Botany' (1888-98) 

 contain a number of papers by him on various points in the biochemistry of 

 plants ; and he contributed several articles to the first series (1894-8) of 

 ' Science Progress.' The most important results of his investigations during 

 this period were the following: — The discovery (' Ann. Bot.,' vol. 1, 1888) 

 that the conversion of inulin into sugar (fructose) during the germination of 

 the Jerusalem artichoke is effected by a specific enzyme, inulase ; the detection 

 of a fat-splitting enzyme (lipase) in the germinating seed of the castor-oil 

 plant (' Boy. Soc. Proc.,' 1890), a subject to which he returned years after- 

 wards (' Boy. Soc. Proc.,' 1905) ; the demonstration of the presence and 

 activity of amyloclastic enzymes in the germinating pollen-grain and in the 

 tissue of the style (' Phil. Trans.,' 1894) ; the analysis of the action of light 

 upon diastase (' Phil. Trans.,' 1897), showing that whereas the red, orange, and 

 blue rays favour the formation of the enzyme, the green, the violet, and 

 especially the ultra-violet rays destroy it, with the striking suggestion that 

 " vegetable structures have a power of absorbing radiant energy which is not 

 connected with the presence and activity of chlorophyll." 



In his later years Green turned his attention mainly to the writing of 

 books, and produced several considerable works, characterised by the lucidity 

 of exposition that he possessed in a high degree. Three of them were text- 

 books : ' A Manual of Botany based upon that of the late B. Bentley ' 

 (1895-6), ' An Introduction to Vegetable Physiology ' (1900), and ' The Soluble 

 Ferments and Fermentation ' (1899). All three went to a second edition, but 

 the third Was the most important and successful of them ; a German transla- 

 tion of it, by Windisch, was published in 1901. Further, he was commissioned 

 by the delegates of the Clarendon Press, Oxford, to write a continuation of 

 Sachs' ' History of Botany ' (1530-1860), to bring the record up to the end 



