Acrid describes that which is pungent, mordant, and of a disagreeable taste. Any excess and any deprivation of saline creates acridity. It is in medicine that the term is commonly employed.

There are as many different types of acrid substances as there are types of salts. There are sour substances, base substances, and neutral substances, which all contain acids and bases in different proportions; one can test the solutions in order to know the type just as one tests salts to know if they are acidic, alkaline, or neutral. See Salts.

Acrid solutions can also be divided into the categories of scurvy or syphilis, etc. When the different salts that are naturally occurring in the liquids of the body are present in disproportionate quantities, or when the natural constitution of these liquids is disturbed, and their natural temperature raised, it creates different types of acrid substances. Certain gangrenous tissue can prove that liquids of the human body can become so acrid that they are caustic. Ureic bases that form naturally in the living body have the property of dissolving animal tissues, not only humors and skin but also nerves and cartilage; and acrid , acidic substances of animals, such as milk acids, soften and dissolve the hardest of bones. One can experiment with sour milk, and one will see that it dissolves anything up to ivory.

Often, an unnatural acrid substance mixes with the humors, and doesn’t produce any substantial ill as long as it isn’t present in large quantities and as long as it is weaker than the natural salts of the body. One often noticed that the people who carried a strain of pox in their humors appeared to be in good health as long as the virus hadn’t made enough progress to make itself known. There are persons with gout who seem in good health during the intervals between bouts of gout although they are carrying the acrid humor of the gout: it’s for this reason that wise and able doctors take into consideration the cause of gout in all the sicknesses that occur to those with gout, as to other men.

Sores from a pestilence can spread suddenly from people who appeared to be in perfect health; when the cause of these sores comes from some interior part of the body, those to which this misfortune occurs die without even the chance for bed rest, and they sometimes even fall dead in the streets while going about their business. This well proves that one can carry within him or herself for quite a while a strain of illness, and of a very dangerous variety, without knowing it. This can only be understood with difficulty by those who, having the pox, conserve all appearances of good health, show no symptoms, and have healthy children.

Often, people are about to have the smallpox and seem to be well; however they have in themselves the strain of this sickness, which in several days will cover them in spots and ulcers. These things are thoroughly and carefully explained in Medicinal Chemistry.