248 ANNUAL OF SCIENTIFIC DISCOVERY. 



to do with the taste of tea, but its presence is most important, on 

 account of the unusually large amount of nitrogen (nearly 30 per 

 cent.) which it contains. It is this substance that makes tea save 

 food, by its action in preventing various wastes of the system, and 

 renders it peculiarly acceptable to elderly persons, in whom these 

 wastes go on very rapidly, while their stomach assimilates less 

 and less of the nutritive portion of food. An ounce of good tea 

 contains about 10 grains of theine, an amount sufficient to pro- 

 duce a peculiar intoxication, and many unpleasant symptoms, if 

 taken in one day. From 3 to 4 grains of theine is a healthy 

 amount for a day, so that 3 ounces of really good tea is more than 

 an ordinary person should take in a week. 



Tannin, the astringent element in tea, is extracted by length- 

 ened infusion, and any one who wishes to avoid the effects of its 

 astringency should drink tea soon after the water is poured over 

 it. The really nutritive element of tea, the gluten, is thrown 

 away with the leaves. The use of soda tends to bring out a trifle 

 more of this element ; but the South American native custom of 

 eating the spent leaves, after the liquor is consumed, appears to 

 be the best way of making sure of the gluten. 



EARTH EATEN IN BORNEO. 



A few years ago the manager of the Orange-Nassau colliery, 

 near Zandjermasin, in the Island of Borneo, found that many of 

 his work-people (natives) consumed large quantities of a kind of 

 clay. A sample of this material was forwarded to Batavia for 

 analysis, and the following is the result in 100 parts : 



Pitcoal resin (organic matter volatile at red heat) 15.4 



Pure carbon " " " " " 14.9 



Silica " " " " " 38.3 



Alumina " " " " " 27.7 



Iron pyrites " " " " " 3.7 



100.0 



The eating of clay is a custom to which savages or, at least, 

 human beings of a very low degree of development are freely 

 given in various parts of the world. No other analyses of any of 

 the substances used as such have been made, or at least, if made, 

 they have not been published. The resident military medical 

 officer at the above-named colliery is strongly inclined to con- 

 sider it the duty of the manager to eradicate and discountenance 

 this habit of the workmen, as it appears to injure their health. 



THE ABUSE OF PHYSICAL EXERCISE. 



The " Westminster Gazette," in the course of a declamation 

 against too much physical exercise, sensibly observes, " Those 

 who have gone through the severest training become in the end 

 dull, listless, and stupid, subject to numerous diseases, and in 

 many instances the ultimate victims of gluttony and drunkenness. 

 Their unnatural vigor seldom lasts more than 5 years. It 

 was especially remarked by the Greeks that no one who in boy- 



