The same author remarks, "Direct experiment has shown, in the clearest manner, the close relation of function existing between the perspiratory and respiratory membranes."
"M. Fourcault, with a view of observing, through different species of animals, the effect of the suppression of perspiration, conceived the notion of having the skins of certain live animals covered with varnish. After having been suitably prepared, some by being plucked, others by being shorn, he smeared them with varnish of variable composition; the substances employed being tar, paste, glue, pitch, and other plastic matters. Sometimes these, one or more of them, were spread upon parts, sometimes upon the whole of the body. The effects of the operation have varied, showing themselves, soon or late afterwards, decisively or otherwise, according as the varnishing has been complete or general, or only partial, thick, thin, &c. In every instance, the health of the animal has undergone strange alterations, and life has been grievously compromised. Those that have been submitted to experiment under our eyes have succumbed in one, two, three days, and even at the expiration of some hours." (See London Veterinarian for 1850, p. 353.)
In a subsequent number of the same work we find the subject resumed; from which able production we select the following:—
"The suppression of perspiration has at all times been thought to have a good deal to do with the production of disease. Without doubt this has been exaggerated. But, allowing this exaggeration, is it not admitted by all practitioners that causes which act through the medium of the skin are susceptible, in sufficient degree, of being appreciated in the circumstances ushering in the development of very many diseases, especially those characterized by any active flux of the visceral organs? For example, is it not an incontestable pathological fact, that catarrhal, bronchial, pulmonic, and pleuritic affections, congestions of the most alarming description in the vascular abdominal system of the horse, inflammation of the peritoneum and womb following labor, catarrhal inflammations of the bowels, even congestions of the feet, &c., derive their origin, in a great number of instances, from cold applied to the skin in a state of perspiration? What happens in the organism after the application of such a cause? Is its effect instantaneous? Let us see. Immediately on the repercussive action of cold being felt by the skin, the vascular system of internal parts finds itself filled with repelled blood. Though this effect, however, be simply hydrostatic, the diseased phenomena consecutive on it are far otherwise.
"It is quite certain that, in the immense system of communicating vessels forming the circulating apparatus, whenever any large quantity of blood flows to any one particular part of the body, the other vessels of the system must be comparatively empty.[14] The knowledge of this organic hydrostatic fact it is that has given origin to the use of revulsives under their various forms, and we all well know how much service we derive from their use.
"But in what does this diseased condition consist? Whereabouts is it seated?
"The general and undefined mode it has of showing its presence in the organism points this out. Immediately subsequent to the action of the cause, the actual seat of the generative condition of the disease about to appear is the blood; this fluid it is which, having become actually modified in its chemical compositions under the influence of the cause that has momentarily obstructed the cutaneous exhalations, carries about every where with it the disordered condition, and ultimately giving rise, through it, to some local disease, as a sort of eruptive effort, analogous in its object, but often less salutary in its effect; owing to the functional importance of the part attacked, to the external eruptions produced by the presence in the blood of virus, which alters both its dynamic and chemical properties.
"But what is the nature of this alteration? In this case, every clew to the solution of this question fails us. We know well, when the experiment is designedly prolonged, the blood grows black, as in asphyxia, (loss of pulse,) through the combination with it of carbonic acid, whose presence is opposed to the absorption of oxygen. But what relation is there between this chemical alteration of blood here and the modifications in composition it may undergo under the influence of instantaneous suppression, but not persistent, of the cutaneous exhalations and secretions? The experiments of Dr. Fourcault tend, on the whole, to explain this. His experiments discover the primitive form and almost the nature of the alteration the blood undergoes under the influence of the cessation of the functions of the skin. They demonstrate that under these conditions the regularity of the course of this fluid is disturbed—that it has a tendency to accumulate and stagnate within the internal organs: witness the abdominal pains so frequently consequent on the application of plasters upon the skin, and the congestions of the abdominal and pulmonary vascular systems met with almost always on opening animals which have been suffocated through tar or pitch plasters.
"They prove, in fact, the thorough aptitude of impression of the nervous system to blood altered in its chemical properties, while they afford us an explication of the phenomena of depression, and muscular prostration, and weakness, which accompany the beginning of disease consecutive on the operation of cold.
"How often do we put a stop to the ulterior development of disease by restoring the function of the skin by mere [dry] friction, putting on thick clothing, exposing to exciting fumigation, applying temporary revulsives in the shape of mustard poultices, administering diffusible stimuli made warm in drenches, trying every means to force the skin, and so tend, by the reëstablishment of its exhalent functions, to permit the elimination of blood saturated with carbonic matters opposed to the absorption by it of oxygen!