156 H. H. Mann— r^e Enzymes of the Tea Leaf. [No. 2, 



then wrote as follows : * " Quite recently I have succeeded after 

 numerous attempts in isolating a minute proportion of a soluble 

 oxidising ferment somewhat similar to the oxidases recently discovered 

 in several plants of different natural orders. The substance in question, 

 which evidently has a considerable bearing on the oxidising properties of 

 the tea, apparently does not exist in the active form in the fresh green 

 leaf, but is changed either during the withering if the leaf is bruised, 

 or during the rolling processes when the various organic acids, etc., are 

 liberated from the cells." This was, I believe, the first announcement 

 of the discovery of a soluble ferment or oxidase in the tea leaf, and 

 of course it meant that Mr. Bamber no longer attributed the changes 

 which take place entirely to the oxidising action of the air independently 

 of ferments of any kind. 



Later in 1900 in a private communication to me, Mr. C. R. Newton 

 of Kurseong stated that he had detected an oxidase in the leaf, but the 

 observation was never published till a few weeks ago.f In the meantime 

 Mr. Aso, a Japanese scientist, has published his discovery of the 

 same ferment, but as I have not been able to get hold of the publication 

 in which he announces his work, J I am unable to say to what extent he 

 has carried his researches. 



My own work was done by the courtesy of Messrs. Finlay, Muir 

 & Co., the Agents, the Amalgamated Tea Estate Company, Ld., the 

 Owners, and Mr. J. D. Gwilt, the Manager of the Moondakotee Tea 

 Estate, Darjeeling, on that estate, during the past tea-making season. 



In trying to ascertain the nature of the changes which occur dur- 

 inf^ the manufacture of tea leaf, it seemed of primary importance 

 to determine to what extent, if any, bacterial action intervened, especially 

 as Mr. Bamber's experiments were not quite convincing on the subject. 

 For this purpose it was necessary to cultivate any organisms which 

 might be present on a medium which would as far as possible eliminate 

 the ordinary putrefactive bacteria and only allow those which could 

 have any effect on the tea leaf to grow. This at once puts out of court 

 such common media as peptogelatin, peptone-agar-agar, or any similar 

 preparations as the basis of cultivation in which, as a matter of fact, a 

 large number of putrefactive organisms (many of them of the Bacillus 

 suUilis type) do actually grow when fermenting tea is placed in contact 

 with them. The medium finally adopted consisted of tea leaf itself 

 ground up finely, and then placed in small patches I to J| inches in 



* Report on Ceylon Tea Soils. Colombo, 1900. 

 t Indian Gardening and Planting. November 7th, 1901. 

 :t Bulletin of the Imperial College of Agriculture, Tokio. 1901. Vol. 4, 

 page 254. 



