Most bitters impart their virtues, both to watery and spirituous fluids. By distillation, their taste is in a great measure destroyed; but, on evaporating the watery solution to a thick consistence, the bitter principle remains unaltered, and is frequently improved. See Extracts.
Dr. Darwin ingeniously observes, that the bitter, narcotic, and acrid juices of plants, are secreted by their glands, for defending vegetables against the depredation of insects, and larger animals. An acrid juice exists in t!:e husks of walnuts, and in the pellicle, or skin, of the kernel; but not in the lobes, onnu-us part. Bitters appear to have been excluded from tire seed, les they might have been injurious to the tender organs of digestion of the embryon plant. In some seeds, however, he adds, there is a bitter quality, which refuses to mix with the oleaginous part; as the oil expressed from bitter almonds is as tasteless as that from the sweet kind.
Vegetable bitters possess the combined properties of astringents and aromatics. Hence they are frequently employed in weakness of the stomach and intestines ; in cold habits, where the bile and humours require to be attenuated or diluted; and for promoting natural evacuations, particularly those by the pores and the urinary canal. They are also of service in many cases of indigestion, loss of appetite, flatulency, etc. when these complaints proceed from muscular "weakness, or a phlegmatic and inert state of the fluids. But, in constitutions where the fibres are tense and rigid, or an immoderate heat and inflammation prevail, the continued use of bitters, especially in the gout, would sensibly increase the disorder, and frequently determine it to the kidneys. Thus the secretion of urine might be greatly checked, to the injury of the patient, and at length either dropsy or consumption would be the natural consequence.
ters are to be considered purely as tonics, which strengthen, or impart new energy to the muscular fibres of the stomach; an effect which is by sympathy communicated to other parts of the body.
Bitter substances are often used as vermifuges, though seldom efficacious ; and externally, as anti septics. In domestic economy, they are, at present, chiefly employed for the destruction of in-sects, etc.; but it deserves to be remarked, that there is scarcely a litter root growing in this island, which might not be converted to very useful purposes.—See Bread.