Suppose an animal to be attacked with disease, and fever supervenes; the whole system is then aroused to cast out this disease: nature invariably points to certain outlets, as the only passages through which the enemy must evacuate the system; and it is the province of the physician to aid in this wise and well-established effort; but when such means are resorted to as in the case of the cow at Waltham, (p. 98,) instead of rendering nature the necessary assistance, her powers and energies are entirely crushed.
Let us suppose a horse to have been exercised; during that exercise, there is a determination of heat and fluids to the surface: the pores of the skin expand and permit the fluids to make their exit: now, if the horse is put into a cold stable, evaporation commences, leaving the surface cold and the pores constricted, so that, after the circulating system has rested a while, it commences a strong action again, to throw off the remaining fluids that were thus suddenly arrested; there is no chance for their escape, as the pores are closed; the skin then becomes dry and harsh, the "coat stares," and the animal has, in common parlance, taken cold, and "it has thrown him into a fever." Now, the cold is the real enemy to be overcome, and the fever should be aided by warmth, moisture, friction, and diffusables. If, at this stage, the cold is removed, the fever will disappear; but if the disease (the cold) has been allowed to advance until a general derangement or sympathetic action is set up, and there is an accumulation of morbific matter in the system, then the restorative process must be more powerful and energetic; constantly bearing in mind that we must assist nature in her endeavors to throw off whatever is the cause of her infirmities. Instead of attacking the disease with the lancet and poison,—which is on the principle of killing the horse to cure the fever,—we should use remedies that are favorable to life. It matters not what organs are affected; the means and processes are the same, and therefore the division of inflammation and fever into a great number of parts designated by as many names, and indicated by twenty times as many complications of symptoms which may never be present, only serve to bewilder the practitioner, and render his practice ineffectual.
PLEURO-PNEUMONIA.
As very little is, at present, known of the nature of this disease, we give the reader the views of Mr. Dun, who received the gold medal offered by the Agricultural Society for the best essay on this subject.
"The causes of the disease, both immediate and remote, are subjects full of interest and importance; and a knowledge of them not only aids in the prevention of disease, but also leads the practitioner to form a more correct prognosis, and to pursue the most approved course of treatment. It is, however, unfortunate that the causes of pleuro-pneumonia have not as yet been satisfactorily explained. No department of the history of the disease is less understood, or more involved in doubt and obscurity. But in this respect pleuro-pneumonia is not peculiar: it is but one of an extensive class which embraces most epidemic and epizoötic diseases. And if the causes which produce influenza, fevers, and cholera, were clearly explained, those which produce pleuro-pneumonia would, in all probability, be easy of solution.
"Viewing the wide-spread and similar effects of pleuro-pneumonia, we may surmise that they are referable to some common cause. And although much difference of opinion exists upon this subject, it cannot be denied that contagion is a most active cause in the diffusion of the disease. Indeed, a due consideration of the history and spread of pleuro-pneumonia over all parts of the land will be sufficient to show that, in certain stages of the disease, it possesses the power of infecting animals apparently in a sound and healthy condition, and otherwise unexposed to the action of any exciting cause. The peculiarity of the progress of this disease, from the time that it first appeared in England, is of itself no small evidence of its contagious nature. Its slow and gradual progress is eminently characteristic of diffusion by contagion; and not only were the earlier cases which occurred in this island distinctly proved to have arisen from contact with the Irish droves, but also subsequent cases, even up to the present day, show numerous examples in which contagion is clearly and unequivocally traceable.... Although pleuro-pneumonia is not produced by the action of anyone of these circumstances alone, [referring to noxious effluvia, &c.,] yet many of them must be considered as predisposing to the disease; and although not its immediate exciting causes, yet, by depressing the physical powers, they render the system more liable to disease, and less able to withstand its assaults. Deficient ventilation, filth, insufficient and bad food, may indeed predispose to the disease, concentrate the animal effluvia, and become the matrix and nidus of the organic poison; but still, not one, alone, of these circumstances, or even all of them combined, can produce the disease in question. There must be the subtle poison to call them into operation, the specific influence to generate the disease."
"On the other hand, it appears probable that the exciting cause, whether it be contagion, or whatever else, cannot, of itself, generate the disease; but that certain conditions or predisposing causes are necessary to its existence, and without which its specific effects cannot be produced. But although these remote or predisposing causes are very numerous, they are often difficult of detection; nay, it is sometimes impossible to tell to what the disease is referable, or upon what weak point the exciting cause has fixed itself. A source of perplexity results from the fact.... The predisposing causes of the disease admit of many divisions and subdivisions; they may, however, be considered under two general heads—hereditary and acquired.
"With reference to the former, we know that good points and properties of an animal are transmitted from one generation to another; so also are faults, and the tendencies to particular diseases. As in the same families there is a similarity of external form, so is there also an internal likeness, which accounts for the common nature of their constitution, modified, however, by difference of age, sex, &c.
"Among the acquired predisposing causes of pleuro-pneumonia may be enumerated general debility, local weakness, resulting from previous disease, irritants and stimulants, exposure to cold, damp or sudden changes of temperature, the want of cleanliness, the breathing of an atmosphere vitiated by the decomposition of animal or vegetable matters, or laden with any other impurity. In short, under this head may be included every thing which tends to lower the health and vigor of the system, and consequently to increase the susceptibility to disease.