Philosophical Society/ of London. 231 



rolled up in the form of balls and threads. He said he 

 had formerly infused all the sorts of green and bohea teas 

 he could procure, and expanded the different leaves on pa- 

 per to compare their respective size and texture, intending 

 thereby to discover their age. He found the leaves of 

 green tea as large as those of bohea, and nearly as fibrous; 

 •which led him to suspect that the difference did not so 

 much depend upon the age as upon the other circumstances. 



The Asiatics give a flavour to tea by introducing among 

 it the olea fraorans, whose small flowers are frequently lo 

 be met with in teas exported from China. On the subject 

 of drinking of tea, Dr. L. observed, that the Chinese and 

 Japanese never use tea before it has been kept a year, by 

 which time its narcotic properties are diminished. They 

 drink it without sugar or milk. Having mentioned various 

 methods of preserving the seeds for vegetation, the lecturer 

 entered upon its medical history. 



It is natural to conclude, that as tea was imported 

 from a foreign country, and at no inconsiderable danger 

 and expense, and the custom of drinking it almost uni- 

 versal, much attention would have been excited respecting 

 its natural and medical history, as well as its commercial 

 influence; and indeed, as the learned President noticed, if 

 saying much is a proof of attention, much has certainly 

 been said and written, and much to no purpose, on its medi- 

 cinal properties ; for although he has examined nearly a hun- 

 dred authors on the subject, he has acquired little informa- 

 tion ; nor can it be expected, where vague hypotheses are 

 substituted for experiment, and theoiies for facts: thus 

 claiming no fixed data, the inductions are fallacious or in-. 

 decisive. This induced the Doctor to institute experiments, 

 and establish principles upon which reason might exercise 

 judgement,and truth elucidate facts. From thescexpernients, 

 which we are sorry our pas,e5 will not allow us room to re- 

 late, the sedative and relaxing effects of »ca appear greatly 

 to depend upon an odorous fragrant principle, which 

 abounds most in green tea, particularly that which is most 

 highlv "flavoured. This seems further confirmed by the 

 practice of the Chinese, who avoid using this plant till it 

 has been kept at least twelve months, as they find whea 

 recent it possesses a soporiferous and intoxicating quality. 



The author deprecated the practice of taking tea very 

 hot, and quoted in support of his opinion a passage from 

 Professor Kalm's Travels into North America. The Doctor 

 concluded by the following observations : '* From the re- 

 sult of the experiments we may clearly explain the cause* 



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