Many serious accidents have arisen from leeches being swallowed in the water of swamps and marshes, too frequently drunk with avidity by the thirsty and exhausted soldier. Larrey mentions several cases of the kind during the French campaign in Egypt, and two fatal instances fell under my observation during the Peninsular war; draughts of salt water, vinegar, and various stimulating injections could not loosen their hold, and they were too deeply attached in the throat to be seized with a forceps. Zacutus Lusitanus had witnessed the same unfortunate results. The leech thus swallowed is generally the _hirudo Alpina_. Norfolk supplies the greater part of the leeches brought to London, but they are also found in Kent, Suffolk, Essex, and Wales. The leeches imported from France differ from ours, in having the belly of one uniform colour. The best are the green, with yellow stripes along the body. The horse-leech, which is used in the north of Europe, but also common in England, is entirely brown, or only marked with a marginal yellow line. A popular belief prevails, that the application of this variety is most dangerous, as they are said to suck out all the blood in the body. SOMNAMBULISM. This singular aberration from our natural habits may be considered an intermediate state between sleeping and being awake. This infraction of physiologic laws may therefore be looked upon as a morbid condition. Physicians have given it various denominations, founded on its phenomena, _nocti-vagatio_, _nocti-surgium_, _noct-ambulatio_, _somnus vigilans_, _vigilia somnans_. Somnambulism was well known by the ancients; and Aristotle tells us, "there are individuals who rise in their sleep, and walk about seeing as clearly as those that are awake."