The chief use of the preparations of lead, however, is as an astringent in acute diarrhoea, particularly if ulceration be present, when it is usefully given in combination with opium in the form of the Pilula Plumbi cum Opio.
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.
Preserves are used to conceal deformities or to protect the eyes in the many conditions where they cannot tolerate bright light, such as ulceration and inflammation of the cornea, certain diseases of the iris, ciliary body, choroid, and retina.
But as the stumps of harpoons are frequently found in the dead bodies of captured whales, with the flesh perfectly healed around them, and no prominence of any kind to denote their place; therefore, there must needs have been some other unknown reason in the present case fully to account for the ulceration alluded to.
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.
But in the more severe forms ulceration of the mucous membrane takes place.
If the eyeball be kept perfectly clean and no organism be admitted from the outside then ulceration will not follow.