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The Natural History of the Tea-Tree, with Observations on the Medical Qualities of Tea, and on the Effects of Tea-Drinking cover

The Natural History of the Tea-Tree, with Observations on the Medical Qualities of Tea, and on the Effects of Tea-Drinking

Chapter 24: EXPERIMENT IV.
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About This Book

The work combines botanical description and practical guidance with a medical survey of tea and its consumption. The first part examines the plant’s classification, morphology, origin, soil and culture, leaf gathering, methods of curing and preparation, recognized varieties, and means of preserving seed, supplemented by illustrations and comparative notes. The second part reviews clinical observations, experiments, and contemporary opinions about tea’s physiological effects and therapeutic uses, and discusses substitutes and public habits of drinking. The presentation seeks to gather dispersed accounts and offer practical recommendations grounded in observation.


SECTION  II.


Nevertheless, as I have often observed that drinking Tea, particularly the most highly-flavoured fine green, proves remarkably relaxing to many persons of tender and delicate constitutions, I was induced to prosecute my enquiries farther.

1. To this end I distilled half a pound of the best and most fragrant green Tea with simple water[78], and drew off an ounce of very odorous and pellucid water, free from oil, and which on trial (Section I. Experiment II.) shewed no signs of astringency.

2. That part of the liquor which remained after distillation, was evaporated to the consistence of an extract; it was slightly odorous, but had a very bitter, styptic, or astringent taste. The quantity of the extract thus procured weighed about five ounces and a half[79].

 



EXPERIMENT  III.

a. Into the cavity of the abdomen, and cellular membrane of a frog, about three drachms of the distilled odorous water (No. 1.) were injected.

In twenty minutes, one hind leg of the frog appeared much affected, and a general loss of motion and sensibility succeeded[80]. The affection of the limb continued for four hours, and the universal torpidity remained above nine hours; after this the animal gradually recovered its former vigor.

b. In like manner some of the liquor remaining after the distillation of the green Tea (No. 1.) was injected; but this was not productive of any sensible effect.

 



EXPERIMENT  IV.

a. To the ischatic nerves laid bare, and to the cavity of the abdomen of a frog, I applied some of the distilled odorous water (No. 1. and Experiment III, 1.). In the space of half an hour, the hindermost extremities became altogether paralytic and insensible; and in about an hour afterwards the frog died.

b. In like manner I applied the liquor remaining after distillation (No. 1. and Experiment III. 2.) to another frog; but no sedative or paralytic effect was observable.

3. From these experiments the sedative and relaxing effects of Tea appear greatly to depend upon an odorous fragrant principle, which abounds most in green Tea, particularly that which is most highly flavoured[81]. This seems farther confirmed by the practice of the Chinese, who avoid using this plant, till it has been kept at least twelve months, as they find when recent it possesses a soporiferous and intoxicating quality. (Part I. Sect. IX.)

Thus often under trees supinely laid,
Whilst men enjoy the pleasure of the shade,
Whilst those their loving branches seem to spread }
To screen the sun, they noxious atoms shed, }
From which quick pains arise, and seize the head. }
Near Helicon, and round the learned hill
Grow Trees, whose blossoms with their odour kill[82].