2. (Ph. L. 1746.) Spanish flies (in fine powder) and wheat flour, equal parts, made into paste with vinegar, q. s. As a blister.
Epithem, Vol′atile. Syn. Epithema volatile, E. ammoniæ, L. Prep. (Ph. L. 1764.) Common turpentine and water of ammonia, equal parts. An excellent counter-irritant; either with or without the addition of a little olive oil.
EPIZOOTIC DISEASES. These are diseases which attack different species of domestic animals in the same manner that epidemics do man. These maladies ravage large tracts of country, frequently causing great mortality amongst the various animals inhabiting the localities visited by them; different animals being assailed by different forms of epizootic disease.
For instance, there is the rinderpest, or plague peculiar to cattle, the typhoid or gastric fever which prevailed so largely amongst horses in this country in 1854, and 1861 and 1862; the smallpox of sheep; the diphtheria affecting oxen, sheep, goats, and pigs; the influenza of horses, and the charbon of pigs. Dogs, cats, tame and wild birds, fish,[277] silkworms and bees, each suffers from a special variety of epizootic disease.
[277] Great mortality has prevailed amongst the salmon during the present year, owing to the attacks of a peculiar white fungus, called the Saprolegnia ferox, a parasite that multiplies so rapidly as speedily to envelope any fish it attacks.
Epizootic diseases are met with in most European countries. They are very common in Russia, where they commit great devastation amongst the horned cattle, 400,000 of which are said to die annually from their ravages. Of epizootics, Mr Finlay Dun says:—“They extend at the same time over large tracts of country, attack in a similar manner great numbers of animals, tend to assume a typhoid form, and withstand badly all depletive treatment. They depend upon some general causes as yet unknown, but which it has usually been thought sufficient to term “atmospheric;” but are always most common and fatal amongst animals breathing impure air, densely crowded, badly fed, or exposed to cold winds; and are generally prevented or robbed of their virulence by guarding against such debilitating causes, and maintaining a high standard of health.”
EQUISE′TIC ACID. In chemistry, a substance identical with ACONITIC ACID (which see).
EQUIV′ALENT. (Equivalency.) In modern chemistry, the equivalent of a body is that weight of it which will exactly replace in a compound 1 atom of hydrogen or 1 atom of either of the other monivalent elements (see Table, below).
Monivalent elements are those which replace one atom of hydrogen in chemical combinations in the ratios of their atomic weights.
One atom of a divalent, trivalent, tetrivalent, pentivalent, and hexivalent element replaces respectively, or is equivalent to, two, three, four, five, or six atoms of hydrogen or of any other monivalent element. (For further information