A more certain cause of preternatural tenuity is acrimony. It may certainly be of various kinds, but we can only perceive with clearness the saline acrimony. Yet we have little doubt of this effect being produced by many other substances. In putrid diseases, Deyeux and Parmentier did not discover an increased proportion of ammonia; but the union of the albumen with the serum was affected, and the crassamentum (see Blood) was weak. Symptoms also of a preternatural tenuity of the blood come on often suddenly, without any evident cause. We dare not then carry the axiom before mentioned to its utmost extent, for causes not yet within the reach of our knowledge, often produce unexpected changes.

A peculiar tenuity of the secreted fluids often occurs, and it may arise from tenuity of the blood, increased, and sometimes inflammatory, action of the secreting vessels. Thus the increased flow of urine arises not only from an abundant proportion of water in the blood, but from the increased action of the vessels, as in hysteria, and sometimes from fright. Increased discharge of bile arises chiefly from increased action, which sometimes is occasioned by mental affections, as a violentfit of anger. In hot weather it appears owing to the increase of that portion of the circulating fluid, whatever it may be, which contributes to its secretion. The tenuity of the semen arises also from increased action, owing to the indulgence of lascivious thoughts, or improper indulgences; of tears and saliva from the same cause, owing often to association. When the increased tenuity is owing to inflammatory action., the secreted fluid is usually acrid, as the tears in measles, the mucus of the nostrils and bronchial glands in coryza and catarrh, the bile in cholera, the urine in nephritis, though in the last instance the increased discharge covers the acrimony. Morbid acrimony of the fluids has been accused as the cause of many diseases; but in the circulating system there are few marks of its existence. When separated by the powers of nature, and carried to the excretories, we perceive only its effects.

Philosophy has divided acrids into mechanical and chemical. Pathology followed, and the mechanical pathologists and therapeutists spoke with much feeling of the wounds which the tender nervous fibrils sustained by cruel angles of salts, or the salutary momentum with which mercury removed obstructions. Even the later disciples of the Boerhaavian school have disused this language, and speak of acrids as chemical only.

Nature has, however, anxiously guarded against the admission of morbid acrimony. The taste discovers, the stomach and the bowels reject, what is highly injurious. What may be less so is often altered by digestion, and the mixture of the fluids which it meets with in that process. If, however, it prevails to any considerable degree, we have reason to think that the lacteals refuse their office. When conveyed to the thoracic duct, it is slowly added to the mass, and largely diluted by the considerable proportion of the circulating fluids, and probably sheathed by the albuminous portion of the blood. But even when admitted, either by its chemical affinity or its specific stimulus, (see Secretion,) it is carried to its appropriate gland, and by that outlet safely, often silently, carried away.

The source of morbid acrimony may be therefore air, meat, drink, condiments, medicines, or poisons; and the air may convey either miasmata or contagion. When we mention condiments, however, as a source of acrimony, we must except common salt. This seems a necessary stimulus to the process of digestion, and probably accompanies, in a small proportion, the chyle, since its acid is found in the ammoniacal salts of the blood, while its alkali appears to have undergone some change by the animal process, and to have become ammonia. We find miasmata and contagion conveyed by the air, in cases of remittents and intermittents; but a more decided acrimony is evident in the causes and consequences of epidemic catarrh and dysentery; of many of the exanthemata, and of some of the phlegmasiae. In diseases of the skin there is also evidently an acrimonious substance eliminated, for the reasons assigned under that article. See Cutanei morbi. In syphilis, in hydrophobia, and many others, it is equally conspicuous.

The animal process, that is, the changes which take place in the system by the exercise of the animal functions, produces an acrimony which -is usually covered by the bland nutriment, constantly supplied till carried off by the fluids, styled, for this reason, excrementitious. If, however, these are retained, or the supply of nourishment withheld, an acrimonious state of the fluids follows. What this acrimony is we do not clearly perceive. It is partly saline, partly, perhaps, the dissipation of, or change in, the albuminous portion of the blood, and very probably some admixture of putrid fluid. When this animal process goes on more rapidly, as in fevers, these changes are more conspicuous. The most evident consequences are, all the symptoms of putrefaction, with gangrene, putrid evacuations, fetid breath, etc.: convulsions and spasms, attributed to this acrimony, appear to come on in consequence of the debility which every degree of putrefaction induces.

The various foods which have been accused as producing acrimony in the primae viae,and afterwards in the fluids, have probably, for the reasons assigned, little influence in this respect. The acid in the stomach produced by the continued use of acids and acescents certainly injures the digestion, and produces in consequence debility; but there is no trace of acid in the blood, none in the secreted fluids, if we except the ureal and arthritic concretions; and of these the latter only can be very obscurely traced to acescent aliment. An alkalescent diet is uncommon. Putrid meat, or rather meat advancing to putrefaction, does not appear injurious, if it neither excites sickness nor uneasiness in the bowels; and though dyspeptic symptoms have been observed after a continued course of alkaline medicines in cases of calculus, no injury seems to have been felt in any other organ. The tetradynamiae have been styled alkalescent plants; and these have been blamed for introducing saline acrimony, but, on the contrary, they are the best remedies for a disease in which this acrimony very evidently exists, the sea scurvy.