642 THE POPULAR SCIENCE MONTHLY. 



upon the heat-supply. By constringing the cutaneous vessels, it con- 

 gests the internal organs and weakens the heart, while it requires some 

 time to restore the equilibrium of the circulation. In rainy weather, 

 the result is still more detrimental. In a climate like ours, exposure 

 to rain is at all times fraught with danger to health, and particularly 

 when one sits still in wet or damp garments for any great length of 

 time. No recess out-doors, on a bitterly cold or rainy day, should be 

 the rule, and gymnastic exercises, calisthenics, motion-songs, etc., 

 should take its place. Every grammar-school should have one room 

 fitted up as a gymnasium. There is a certain amount of nerve-energy 

 that is accustomed to find outlet in the muscles, and, if unduly re- 

 pressed, it will often break through the strictest discipline and cause 

 the teacher much annoyance. It must not be forgotten that muscles 

 were not created to be kept still during waking hours, and, when kept 

 at rest an hour or two, a surplus of energy accumulates, which recess 

 gets rid of legitimately. It also serves another purpose admirably. 

 Of all sedatives of the nervous system, muscular exercise is the most 

 efficient, because physiological. It quickens the circulation, and stimu- 

 lates the heart and all the vegetative functions. 



After exercise, the muscles of the hand and forearm particularly 

 are subject to rhythmic, automatic waves of contraction ; that is, 

 there is a tremor beyond the power of the will to control. So that 

 writing and drawing, which require great steadiness of the hand and 

 fingers, should never be taken up after recess, or at the commence- 

 ment of the afternoon session. Of the elementary studies, mental 

 arithmetic involves the closest application of the highest powers of the 

 mind drawing at once upon memory, reason, and judgment and this 

 may be taken up advantageously from half -past eleven to twelve. 

 Breakfast digestion is then nearly if not quite completed, and intense 

 application is least detrimental to the vegetative system. 



The morning meal is usually light in material and amount ; dinner, 

 partaken of soon after noon (except in the largest cities), is the prin- 

 cipal meal. It is " solid," in a physiological not less than in a popular 

 sense, for it is most generous in amount, and usually rich in nitrogen- 

 ized matters flesh-meat, .puddings, eggs, etc. After its ingestion, the 

 digestive organs are taxed to their utmost capacity, and soon become 

 loaded and distended with blood. The digestive system is quite ex- 

 tensive, and is richly supplied with blood-vessels, which are imbedded 

 in rather loose tissue, so that they may dilate, to accommodate the 

 sudden influx from the outlying portions of the body, together with 

 the newly-absorbed products of digestion. The brain is thus deprived 

 of its full supply ; and if, by reason of severe study, it draws upon the 

 circulation, the digestive organs are robbed of their needs, and their 

 efficiency interfered with seriously. Intense application at this time 

 does harm in another way. All the functions of the body are under 

 nervous control. The digestive organs are mainly innervated by the 



