Edible Products. 



74 



[Feb. 1907. 



importance, and to them must be added another, (as in the case with all perennial 

 crops) (4) the effect of the treatment on the plant itself. In auy experiments which 

 may be made, if the information is to be complete, we must determine. 



(1) the resulting increase or decrease in outturn of leaf, 



(2) the change in the character and quality of the leaf, 



(3) the increased or diminished capacity of the soil for producing 

 further crops. 



(4) the change in the character of the bush. 



VARIATIONS IN OUTTURN. 



Of these points the first, is, at first sight, easy of accurate measure ; it 

 seems only to depend on exact weighments of leaf from the differently treated 

 areas at each plucking, and the arrangement that the same plnekers shall visit 

 different plots at each round. But this is not enough. One day the leaf comes 

 in wet, and this wetness cannot be allowed for with any accuracy. The same weight 

 of leaf at different seasons will make different amounts of tea depending on the water 

 naturally present in the leaf, which constantly differs. It is hence absolutely 

 essential not only that the leaf weights be carefully and accurately taken, but that 

 the actual weight of dry material should be determined on each occasion, on the 

 leaf as weighed in from the garden. 



VARIATIONS IN QUALITY- 



The second point — the determination of the quality of the leaf — is however, 

 the most difficult matter of all, and we cannot pretend to have, by any means, solved 

 it. The method which at first appears the natural one, is to make the leaf into tea, 

 and get the latter valued ; but, save in very exceptional cases, this is obviously 

 impossible, unless such large areas are treated that all hope of their being naturally 

 of even character is lost. Furthermore, it is quite probable that slight changes in 

 the method of manufacture will lead to teas which are of different character and 

 hence not directly comparable by a tea taster. We are, therefore, compelled to 

 adopt some method of analysing the leaf as it is received from the garden, if any 

 conclusions as to the effect of the treatment on the quality is to be obtained. A 

 satisfactory method of analysis is, however, still to seek. But, in the meantime, we 

 can obtain a very fair idea of the relative commercial value of leaf grown on the 

 same place and under otherwise similar conditions by getting to know the maximum 

 amount of matter disolved by water under constant conditions more or less resem- 

 bling those used in actual tasting. In carrying this out we have, however, had to 

 diverge considerably from tasting conditions, which are not exact enough for our 

 purpose. For instance, in tasting the result is known to depend materially on the 

 amount the leaf is broken up, hence all our samples have had to be reduced to a 

 standard size, and the only possible exact one was a very finely divided powder. 

 The method finally adopted is given in technical language in the foot note below, 

 but the relative quantities of leaf and water are very similar to those used by 

 tasters. In the liquor obtained we intend also ultimately to determine the amount 

 of tannin, the source of pungency and, when fermented, of colour in tea ; and the 

 quantity of caffeine. The determination of flavour is, at present, beyond the 

 resources of analysis. The constituents in the leaf which are insoluble in water, 

 have no direct practical interest, and hence are not dealt with. Such a method may 

 be considered as giving us at present the best means of judging of the relative value 

 of two lots of leaf, provided of course, the land and situation, and condition of growth 

 are similar. ____ 



Five grammes of the dried leaf ground so as to pass through a sieve of 60 meshes to the inch, are 

 weighed out into a 250 cc. flask, 200 cc. boiling water are added, and the whole shaken for 3 minutes in a 

 shaking machine, and then heated in steam for ten minutes. 1\ minutes shaking follows, and the liquor 

 is made up to the mark with boiling water. After thorough mixing the whole is rapidly cooled in water, 

 made up again to 250 cc. and filtered. 50 cc. of the filtrate is evaporated to dryness and weighed, 



