There are two iodides of mercury, the yellow Mercurius iodatus flatus (mercurous iodide, Hg2I2), usually called Protiodide of mercury or Mercurius prot., and the red, mercurius iodatus ruber (mercuric iodide, HgI2, usually called Biniodide of mercury, or Mercurius bin.
Both these iodides are used in throat affections, ranging from simple follicular tonsillitis to diphtheria, and both are used in syphilitic conditions, Allen giving the preference in the latter to Mercurius bin., as it contains more iodine.
He speaks of it in this way : Mercurius bin. ” has been found useful by many physicians in true syphilis, which is doubtless due to the iodine in the combination, though the depressing effects of the mercury undoubtedly determine a more marked action of the iodine than would be obtained if the iodine were uncombined with it.”
Mercurius prot. is of value in catarrh of the frontal sinuses (96), with offensive discharge from the nose and dull, boring, pressing pain over the eyes. It is also of frequently use for chronic catarrh of the posterior nares (143), with much thick mucus dropping into the throat and constant efforts to swallow. In throat conditions we find Mercurius prot. given as beginning, or worse on the r. side, and Mercurius bin. worse on the 1. side. Allen tells us that Mercury, having a preference for the r. side of the body and Iodine for the 1., the greater proportion of Iodine the salt has, the more 1.sided it becomes, overpowering the r. sidedness of mercury. But he also salts, “that while this holds good in some cases, it is not a very sage guide in practice” (lecture). Merc.bin. is my individual preference in follicular tonsillitis, either side, and Allen says that there is in general more fever and more tendency to headache in the bin. than in the prot.
Both iodides, and especially Mercurius prot., have tongues with a thick, dirty, dirty-yellow portion being more or less clean.
I use Mercurius prot. 1st and Mercurius bin.,3d.