140] D I S diseases, in a great measure depend upon the prevailing refinements in the extensive department of luxury.
The passions are another fruitful source of disorders. Man is perhaps more violently attacked, and more obstinately governed, by them than any other creature. These emotions variously affect the human body: the most hurtful and oppressive of them, however, are terror and grief; the former in particular is often attended with the most fatal effects. The remedies to which we resort during the prevalence of passion, too frequently lay the foundation of lingering disorders both mental and corporeal, in which medicine can afford but precarious relief.
The last source of diseases to which we shall allude, is a variety of specific contagions; the greater part of which is probably generated in the atmosphere. Such is parti- cularly the case with respect to air that is vitiated by putrid, marshy, or noxious vapours, and by the un- wholesome effluvia of various ma- nufacturing processes, especially those of combustion, fermentation and putrefaction. Lastly there is another and very numerous class of contagious maladies, that perpetu- ally migrate from one individual to another, such as the small-pox, measles, hooping-cough, influenza, putrid fevers, &c. of which we shall treat in their alphabetical places. — See also Contagion and Infection.
Every disease weakens the di- gestive powers. The diet ought therefore in all cases to be light and easy of digestion. Paying due at- tention to this circumstance alone, without having recourse to those pernicious nostrums and pretended specifics) now in general circula- tion, will in a very great measure contribute to the recovery of the patient. Medicines are doubtless of considerable utility, when pro- perly and opportunely administer- ed; but an indiscriminate use of drugs (such as prevails among the ignorant and fanciful), cannot fail to be productive of the the worst consequences. See Chronical Diseases, vol. i. p. 521, and foll.
Diseases of Plants are divided by Tournefort into the following classes: 1. Those which arise from too great an abundance of sap; 2. From having too little; 3. From its bad qualities; 4. From its une- qual distribution; and 5. From ex- ternal accidents.
An abundance of sap causes plants to vegetate so luxuriantly, that they seldom arrive at the re- quisite degree of perfection. Wheat is in some climates subject to a dis- ease of this nature, in consequence of excessive vegetation, without producing ripe grain. Such a de- fect may likewise be artificially in- duced, by planting any species of corn in too rich a soil: — too much rain will be attended with a similar effect. When a vegetable is sup- plied too abundantly with juices, it is very apt to rot; one part of it overshadowing the other, so as to prevent the access of fresh air, for want of which it prematurely un- dergoes putrefaction. In grasses, however (fescue excepted), or in any herbaceous plant, too great luxuriance, so far from being a dis- ease, is a very desirable property. According to Dr. Home ("Prin- ciples of Agriculture and Vegeta- tion") dung is a great preventive of diseases, arising from abundant moisture. The want of nourish- ment in plants may be easily ascer- tained by their decay; in which case
