Closely connected with these are the so-called dendroid or dendritic marks, which are dark-colored reddish bands or stripes, often more or less dichotomously branched, not disappearing under pressure, found on the bodies of those struck by lightning. Though usually of the form mentioned, they may assume other shapes, as that of an irregular star with zig-zag rays. Balfour has figured an excellent example of these.
Metallic staining of the skin has been known to occur where metals were in contact with it at the time of the lightning stroke. These stains may be permanent and are due to the introduction of the finely divided metal. Richardson has succeeded in producing this artificially in animals. He found two conditions required, that the metallic conductor should be sufficiently fine to offer resistance to the current and that the current itself should be an electric discharge of low tension.
Loss of hair is said to have occurred from lightning, though the hair was not burnt. One case has been reported where after a severe stroke all the hair on the body is said to have fallen out.
Symptoms.
Under this heading we shall consider only such symptoms as are, so far as can be ascertained, the direct result of the electricity and not those secondary to injuries.
We will consider first those relating to the nervous system.
Loss of Consciousness.—This occurs to a greater or less extent in all but the very mildest cases. It varies throughout all degrees from a slight momentary benumbing of the faculties to the most profound stupor or coma. It may then last hours or even days. On recovery the patient is apt to have some loss of memory, to be dazed and confused for some time, and a certain obtuseness or blunting of the intellectual faculties may persist for a considerable period. This loss of consciousness is often accompanied by flushing of the face and dilatation of the pupils, or on the other hand the patient may present all the symptoms of collapse.
Loss of memory in regard to the lightning stroke after recovery of consciousness is not rare. It is frequently complete so far as any recollection of the lightning goes, and there may be no remembrance of the thunder-storm. Sometimes a defective memory persists together with general mental impairment (James).
Mental Disease.—A condition of mental impairment lasting at least weeks or months may occur. Mania and the delirium of terror are said to have occurred.