When the trigeminus nerve is divided (Majendie), or when its root is compressed injuriously, say Iby a tubercular tumour, the cornea begins to show points of ulceration, which, increasing in area, may bring about total disintegration of the eyeball.
The subsequent experiments of Snellen, Senftleben, and, more lately, of Turner, seem to show that if the eyeball be protected from the impingement of foreign particles, an accident to which it is liable owing to its state of anaesthesia, the ulceration may be warded off indefinitely.
If the eyeball be kept perfectly clean and no organism be admitted from the outside then ulceration will not follow.
Its special uses are in ulceration of the mouth or tongue (ulcerative stomatitis), tonsillitis and pharyngitis.
On the other hand, when the ulceration is old and the circulation through it poor, the aim of the therapeutist is to reawaken the normal reparative process, to bring about increased circulation and increased tissue change, and thereby insure healing.