The exact physiological action of the iodids of mercury has not received the same study and investigation as has been given to either the element itself, or to its salts of the mineral acids. It is known that both the red and yellow iodid of mercury, produce effects similar to those of the uncombined metal, yet otherwise identical effects are modified by the iodin content of the compounds.

In general it is assumed, that the iodids of mercury produce a group of symptoms, following their administration, in which both mercury and iodin effects are plainly visible and that the base and the radical in these salts play practically an equal part in causing their physiological actions. Mercurius iodatus ruber has an action almost exactly like that of the iodatus flavus, but it is believed that the former salt is more toxic and that the iodin in it modifies its action to a greater degree, than is the case with the latter compound. Both of these preparations produce some degree of salivation and the other manifestations of their action - being a cross between mercury and iodin - are accompanied by mild inflammatory and febrile symptoms, more so than would result from equal doses of any of the other mercury compounds, the cyanid and bi-chlorid excepted. Thus, the throat, which seems to be especially susceptible to the effects of these iodids, becomes sore and inflamed, and a slight rise in temperature has been noted. Furthermore, these salts affect the intestinal tract, producing constant desire for stool, with tenesmus. All these symptoms are more prominent with the red than with the yellow iodid.

Therapeutics

Mercurius biniodidus, Mercurius ioda-tus ruber, in its more general characteristics resembles Mercurius solubilis itself, which means that it has the aggravation of its symptoms at night, the easy perspiration and the tendency to glandular swelling. In its effects, however, Mer-curius biniodidus is left-sided and this is particularly marked in its throat symptoms.

The remedy is, therefore, of frequent use in attacks of simple pharyngitis, or of tonsilitis which commences on the left side of the throat The submaxillary and oilier glands on the left side of the throat and jaw are swollen and painful, there is more or less salivation or at least an increased amount of saliva, the tongue is heavily coated yellow and the taste is bitter or metallic. On swallowing there is soreness, at first on the left side and later spreading all over the throat. In follicular or cryptic tonsilitis with specks or patches of exudation upon the tonsils, this remedy is certainly of value.

In indolent chancre, and bubo, Mer-curius biniodidus may be needed.

Characteristic Symptoms Of Mercurius Biniodid

1. Tonsilitis; glands greatly swollen, very red and inflamed; usually begins on left side. Often required in diphtheria. In Mercurius protoiodid there is less inflammation and swelling of glands, and the throat is dotted with mucous patches; follicular tonsilitis.

2. Mercurius biniodid is left-sided in action, whereas Mercurius protoiodid is right-sided. This differentiation is of practical clinical value, in throat affections particularly.