FACIAL PARALYSIS, although locally affecting but a small part of the body, is of such frequent occurrence as to require separate description. In this affection there is more or less perfect loss of power over all the muscles supplied by the portio Jura or facial nerve. This interference with the functions of the nerve may he clue to lesions in the cortex affecting facial fibres of the corona radiata or internal capsule, to lesions in the nucleus of the nerve, or to lesions of the nerve trunk. Facial paralysis due to lesions in the cortex is commonly associated with hemiplegia. This paralysis is on the same side as that of the body, the nucleus from which the facial fibres originate being connected with the opposite side of the cortex in a manner quite similar to that by which the anterior horns are associated with the opposite hemisphere. Facial paralysis due to lesions of the facial nucleus in the medulla is uncommon. Tumors, hemorrhages, softening, the toxins of diphtheria, and the extension of an anterior poliomyelitis are the most frequent causes. Lesions of the trunk of the nerve may occur in any part of its course. due to tumors. injury, inflammation, etc. When the lesion af fects the nerve fibres as they pass through the lower portion of the polls, and involves also the pyramidal or main motor tracts, there results the so-called 'cross paralysis,' i.e. a paralysis of the face on the same side as the lesion and of the trunk upon the opposite side. The following graphic account of the appearance of a patient suffering from facial paralysis is condensed from Watson. Lectures on the Practice of Physic. From one-half of the countenance all power of expression is gone: the features are blank. still, and unmeaning: the eyelids apart and motion less. The other half retains its natural cast, except that in some cases the angle of the mouth on that side seems drawn a little awry, in eon sequence of want of counterpoise from the corre sponding muscular fibres of the paralyzed side.
The cannot laugh, weep, frown, or ex press any feeling or emotion with one side of the face, while the features of the other side may be in full play. lie cannot spit or whistle prop erly. One half the aspect, with its unwinking eye, its fixed and solemn stare, might be that of a dead person; the other half is alive and mo bile.
If the cause of the paralysis is due to condi tions in the nerve external to the cranial cavity, there is little danger to life and good chances for recovery from the paralysis. If, however. the paralysis is dependent upon intra-cranial con ditions, there is not only less chance of recovery from the paralysis, but great danger to life.
There yet remain to be considered certain con ditions which are popularly called paralyses or palsies. but which are essentially different from those already described. Among these may be mentioned the so-called 'shaking palsy.' or par alysis agitans (q.v.), and the palsies induced by various poisons. The poisons which are the most common causes of paralysis or of tremors are alcohol, lead, tobacco, and mercury. Arsenic and opium are rare causes. It is upon the peri pheral nerves that these poisons seem to have their most pronounced effect, setting up a toxic peripheral neuritis.
A specific form of paralysis of the lower ex tremities, consequent on the use of flour from the beans of the Lathyrus sativus, is common in certain parts of India and Tibet. The ripe bean is an ordinary article of food when made into flour, but it is generally used with wheat or barley flour. It is said to be injurious only when it exceeds one-twelfth part of the mixture and to cause paralysis only when it constitutes more than one-third. Other species of Lathy rus have been known occasionally to cause simi lar symptoms in European countries.