(6) Impurity of the atmosphere in which they habitually or daily reside must be carefully shunned for young children, especially for the nervous. The kind of dull and diffused headache which children often complain of, after study for some time in a close, ill-ventilated school-room, is very likely (if the bad influence be continued for a number of years) to develop itself, at puberty, into a regular migraine. Purity of air in the school-room must therefore be scrupulously provided for; and the same thing must be attended to as regards the sleeping rooms.
Of the climatic influences we may speak in a few words. Besides the avoidance of distinctly malarial districts, and also of places where, although there is no distinct ague, there is a prevalence of neuralgic or even of so-called "rheumatic" complaints, it is necessary very carefully to shun damp soils, and places where there is a great deal of harsh and cold wind. Mere lowness of average temperature is not in itself a strong predisposer to neuralgia, at any rate if guarded against by abundant food and the use of such clothes as will prevent children from ever feeling chilly and depressed. But damp and harsh winds are actively bad; and when joined to habitual or frequent lowness of temperature, they constitute very unfavorable surroundings for the nervous systems of delicate children.
(_b_) We come now to the prophylaxis which is to be adopted in the intervals of the paroxysms when neuralgia has been actually set up. This consists essentially in three things: (1) Physiological rest, as perfect as possible, of the affected parts; (2) protection from cold; (3) protection from sunlight; (4) avoidance of injurious mental emotions.
(1) The maintenance of physiological rest, to the greatest extent that is possible, is an absolute necessity, if we would shield a nerve, which has lately been attacked with neuralgia, from fresh paroxysms. The most evident illustrations of this fact are afforded by those neuralgic affections in which it is most difficult to adopt this precaution. Thus the greatest embarrassment from this cause is met with in the case of sciatica; a mild case is often converted into one of great severity and intractability because the patient, in the early stages, either cannot or will not maintain the recumbent posture. So, too, though in less marked degree, the cure of cervico-brachial neuralgia is often greatly impeded by the difficulty of maintaining complete rest of the limb. Again, in neuralgia affecting the third division of the fifth, the movements of mastication and of speech are a terrible hinderance to the progress of recovery; and it often becomes necessary, in severe cases, to prescribe absolute silence, and even to feed the patient exclusively with such liquid or semi-liquid food as shall require no efforts of chewing.