In these deeper-seated inflammations benefit may be obtained from strong nitrate of silver applied on this principle of counter-irritation. The best position for the application has been much discussed, some placing it as near the part as possible, others insisting that it shall be between the heart and the inflamed tissue, and others that it shall affect vessels which receive their supply from a different source than the affected part. The simple rule adopted by Mr. F. Jordan, with much success, is to apply the nitrate over the adjacent vascular territory; thus, in orchitis he acts upon the great vessels in the groin and front of the thigh (Practitioner, vol. ii.). In synovitis it is used round the affected joint, though iodine is usually preferred in this disorder.

In irritation of the prostate gland or seminal ducts, it may be applied to the perineum, rather than to the urethral membrane itself.

4. As a Direct-irritant (the "medication excitative" of Trousseau), the nitrate finds some applications.