Belonging to the measles. Morbus, (from death"). A disease; malum, nosos. ' A disease we have already defined to be "that condition of the human body in which the actions of life and health are not performed, or performed imperfectly." (See Causae.) The various imperfections in the functions therefore constitute it, a circumstance which the accurate distinction of diseases, according to nosologists, renders indispensable.

Diseases may therefore be as different as the functions 4njured, but this would render them too numerous, and it has consequently been usual in the morbi universales to combine a certain number of the injured functions to constitute one disease. In the local diseases, one injured function has been supposed alone to cons.itute a genus. Diseases, however, differ, either as many persons are usually affected at the same time, and they are then styled epidemic; or, as peculiar to one country, and called endemic: when they occur accidentally, they are styled sporadic. They differ also as the mind or body is affected; as any particular organ suffers; or from the cause which has produced them: but such varieties are now disregarded; and those who pursue distinctions for the sake of diagnosis, at this time, arrange diseases from their symptoms. See Nosologia.

While we omit many useless disquisitions respecting disease in its abstract, we have referred to this article for the more general pathological inquiries, and shall proceed to consider the morbi fluidorum; solidi simplicis; solidi vitalis; and morbi solidorum con-tinextilm, in their order.

Morbi flcidorum. We begin with diseases of the fluids, as in this form our nutriment is taken in, and, if these are defective, the whole system will suffer; though we shall soon endeavour to establish this axiom, that the state of the fluids, in the body, depends on that of the solids, particularly the vital solid. We have already had occasion to observe, that every deviation from the sound state is not disease, but that there are different degrees of such deviations within the limits of health, though probably each may be supposed to form a predisposition to disease.

Diseased fluids are said to differ from those in the natural state, from a difference in their cohesion, or from any acrimony, formed either by the animal process, or introduced with the air or aliment. The cohesion of the fluids may be too great, constituting tenacity and lentor; or too little, when they are said to be in a dissolved state. The blood, to which these diseases are chiefly confined, we have found consisting of different parts in a state of mixture only, and the lentor can be owing only to a diminution of the proportion of water, or a less proportion of neutral salts, by which some of the gluten is kept in solution. It may be doubted whether the excess of the fibrin or gluten may not produce a similar effect, but this we shall soon consider.

The causes of lentor, which result from a diminution of the watery portion of the blood, are said to be a deficiency of drink, an increase of the fluid secretions, a stagnation and absorption of the watery parts separated from the crassamentum. Each of these causes, however, is imaginary, so far as regards this change, for the secretions are so nicely balanced, that an increase of one is followed by a diminution of the other; and when fluids are not thrown in, they are, in a great degree, checked. Thus, a nurse who has not drank any thing for a long time, is not greatly loaded with milk, but immediately, on drinking, it flows freely. The circulation also keeps up the union between the discordant portions of which the blood consists; and while the secretions are supported, no stagnation of watery fluid can take place.

The idea of Gaubius, that a glutinous matter, arising from foods of this kind which absorb water, from a weaker digestion, a more languid circulation, or insufficient exercise, is certainly imaginary; for the glutinous foods produce no such effect, and the other causes of this supposed gluten rather contribute to lessen the tenacity of the fluids. The earthy substances and their various sources, supposed to have the same effect, rest on a foundation equally insecure. The opinion has not a single fact for its support. We know indeed but one cause of lentor, high health, with a consequent increase in the proportion of the gluten and fibrin of the blood; but this is connected with increased tone, and more powerful action of the arterial system, which prevents any bad effects, but which itself constitutes predisposition to disease, under the appellation of diathesis phlogistica. See Inflammatio.

Increased tenacity in the secreted fluids is more common; but we chiefly perceive it in the bile and the mucous follicles. It never appears to arise from any defect in the blood, but from stagnation in consequence of debility, sometimes in consequence of a want of irritability in the excretory ducts. We certainly see, in the urinary organs, that the state of the fluids, from which the urine is secreted, influences the nature of this discharge and a suspicion may arise that a similar effect may produce morbid bile, but in neither case is.

the morbid fluid referrible to lentor; and the idea of earth joined with acid, so as to form a"pitchy acrimony," is neither supported by observation nor chemical experiment.

Too great fluidity is in part owing to an excess of watery fluids, and such a change undoubtedly takes place; but the causes usually assigned are often imaginary. Too large a proportion of watery fluids is corrected by the increase of the watery secretions, and increased evacuations from some glands are generally compensated by the retention of other secretions. In this view an indolent life and a humid atmosphere produce certainly some effect; but the principal diseases which they previously induce are general debility and impaired digestive powers: from hence proceeds the deficiency of the gluten and fibrin; and, of course, the greater tenuity of the serosity.