"The consequence of external motion upon the blood will be best elucidated by what may be seen to occur in a column of mercury similarly circumstanced.

"A barometer, when carried out to sea in a calm, rests at the same height at which it would stand on shore: but when the ship falls by subsidence of the wave, the mercury is scen apparently to rise in the tube that contains it, because a portion of its gravity is then employed in occasioning its descent along with the vessel; and according ly, if it were confined in a tube closed at bottom, it would no longer press with its whole weight upon the lower end. In the same manner, and for the same reason, the blood no longer presses downwards with its whole weight, and will be driven upwards, by the elasticity which before was merely sufficient to support it.

"The sickness occasioned by swinging is evidently from the same causes as sea sickness; and that direction of the motion which occasions the most piercing sensation of uneasiness, is conformable to the explanation above given.

"It is in descending forwards that this sensation is perceived; for then the blood has the greatest tendency to move from the feet to wards the head, since the line joining them is in the direction of the motion. But when, in the descent backwards, the motion is transverse to the line of the body, it occasions little comparative inconvenience, because the tendency to propel the blood towards the head is then inconsiderable.

"The regularity of the motion in swinging, afforded me an ap parently favourable opportunity for trying the effect of inspiration; but although the advantage was manifest, I must confess, it did not fully equal the expectations I had formed from my experience at sea. It is possible that the suddenness of the descent may in this case be too great to be fully counteracted by such means; but I am inclined to think that the contents of the intestines are also affected by the same cause as the blood; and if these have any direct disposition to regurgitate, this consequence will be in no degree counteracted by the process of respiration.

"A friend of mine informed me, that he had endeavoured to counteract this mechanical effect upon the stomach, and had experienced immediate relief from a slight degree of sea-sickness, by ly. ing down upon the deck, with his head towards the stem of the vessel; by means of which, upon pitching, he was in the attitude of a person descending backwards in a swing.

"Whether the stomach be or be not thus primarily affected, or only by sympathy with the brain, the sensation of sinking is in all cases referred directly to the stomach, which is seized with such instantaneous retching, that no person, who has not been so situated, can form a just conception of it.

"In thus referring the sensations of sea-sickness in so great a de. gree, to the agency of mere mechanical pressure, I feel confirmed, by considering the consequence of an opposite motion, which by too quickly withdrawing blood from the head, occasions a tendency to

faint, or that approach to fainting which amounts to a momentary giddiness, with diminution of muscular power. At a time when I was much fatigued by exercise, I had occasion to run to some distance, and seat myself under a low wall for shelter from a very heavy shower. In rising suddenly from this position, I was attacked with such a degree of giddiness, that I involuntarily dropped into my former posture, and was instantaneously relieved by the return of blood to the head, from every sensation of uneasiness.

"Since that time, the same sensation has frequently occurred to me in slighter degrees, and I have observed that it has always been under similar circumstances of rising suddenly from an inclined position, after some degree of previous fatigue. Sinking down again immediately removes the giddiness; and then, by rising a second time more gradually, the same sensation is avoided.

"Part III. On the salutary Effects of Riding, and other Modes of Gestation.

"In the preceding instances of disturbing the circulation of the blood, by external motion, the effect is disagreeable, and proportionally prejudicial. There may indeed be cases of disorder, in which it will be salutary; but these are probably less frequent than is generally supposed.

"In the observations which follow, general opinion will concur with me, on the benefit derived from external, or passive motion ; and I hope, that in ascribing its good effects to their true cause, I shall enable others to make a valuable distinction, which has not yet been preserved with due care, between one motion which is salutary, and another which is very frequently pernicious. For, although the term gestation is employed by medical writers, as a general term comprehending riding on horseback, or in a carriage, and although the merits of such motions, especially the former, were clearly no. ticed, and perhaps even overrated, by the discernment of Syden. ham, I believe that no explanation has yet been given, of the peculiar advantages of external motion, and am persuaded, that the benefits to be derived from carriage-exercise, are by no means in so high estimation as they ought to be.

"Under the common term exercise, active exertion has too frequently been confounded with passive gestation, and fatiguing efforts have consequently been substituted for motions that are agreeable, and even directly invigorating, when duly adapted to the strength of the invalid, and the peculiar nature of his indisposition.

"The explanation which I am about to offer, of the effects of external motion upon the circulation of the blood, is founded upon a part of the structure observable in the venous system, the mechanical tendency of which cannot be doubted. The valves which are everywhere dispersed through those vessels, allow free passage to the blood when propelled forward, by any motion that assists its progress; but they oppose an immediate obstacle to such as have a contrary tendency. The circulation is consequently helped forward by

every degree of gentle agitation. The heart is supported in any laborious effort that may have become necessary, by some obstacle to its exertions; it is assisted in the great work of restoring a system, which has recently struggled with some violent attack; or it is allowed, as it were, to rest from a labour, to which it is unequal, when the powers of life are nearly exhausted by any lingering disorder.

"In the relief thus afforded to an organ so essential to life, all other vital functions must necessarily participate: and the various offices of secretion and assimilation, by whatever means they are performed, will not fail to be promoted during such comparative repose from laborious exertion.

"Even the powers of the mind itself, though apparently least likely to be influenced by mere mechanical means, are manifestly, and in many persons, most immediately affected by these kinds of

motion.

"It is not only in cases of absolute deficiency of power to carry on the customary circulation, that the beneficial effects of gestation are felt, but equally so, when comparative inability arises from redundancy of matter to be propelled. When, from fulness of blood, the circulation is obstructed, the whole system labours under a feeling of hurry and agitation, with that sensibility to sudden impressions, which is usually termed nervousness. The mind becomes incapable of any deliberate consideration, and is impressed with horrors that have no foundation, but in a distempered imagination.

"It is in moderate degrees of this species of affection, that the advantages of carriage exercise are most sensibly felt. The composed serenity of mind that succeeds to the previous alarm, is described by some persons with a degree of satisfaction, that evinces the decided influence of the remedy. With this steadier tone of mind, returns its full power of cool reflection; and if the imagination becomes more alive than usual, its activity is now employed in conceiving scenes that are amusing and agreeable.

"As an instance of direct relief to a circulation, labouring from mere fulness of blood, I may adduce that of a person, whose friends, as well as himself, were apprehensive, from the violent and visible throbbing of his heart, of the existence of some organic mischief, and were in some measure alarmed for the consequences.

"He was persuaded, and not reluctantly, to go without delay, for medical advice, and was accordingly conveyed in a carriage to the house of some physician of eminence, but did not succeed in finding him at home, As the symptoms did not appear to admit of delay, and were at least not aggravated by the motion, it was hoped that the wished for advice might be obtained at a part of the town which happened to be at some distance. But the second attempt proved to be as fruitless as the former, and a third was made with the same event. Since the throbbing had by that time considerably abated, he was contented to postpone any further efforts to the fol. lowing day, and directed the carriage homewards. By the time that he returned to his friends, he found that the motion of travelling

ver several miles of pavement, had apparently removed the complaint. The pulsation of the heart and arteries had subsided to their natural standard; and he congratulated himself, that his search of a remedy had not been ineffectual, although he had been disappointed as to the source from which he thought he had most reason to expect relief.

"If vigour can in any instance be directly given, a man may certainly be said to receive it in the most direct mode, when the important service of impelling forward the circulation of his blood is performed for him by external means. The main spring, or first mover of the system, is thereby, as it were, wound up; and although the several subordinate operations of so complicated a machine, cannot be regulated in detail, by mere external agency, they must each be performed with greater freedom, in consequence of this general supply of power.

"In almost every treatise on the subject of chronical diseases, are to be found numerous instances of the benefit produced by the several modes of gestation which have been most generally adopted; as riding on horse-back, in carriages, sea voyages, and swinging. And, in many cases which might be adduced, it has appeared too clear to admit of a doubt, that the cure of the patient has been owing solely to the external agitation of his body, which must be allowed, at least, to have had the effect above explained; that of relieving the heart and arteries from a great part of their exertion in propelling the blood, and may therefore have contributed to the cure, by that means only. "The different modes above mentioned, are adapted, from their nature, to different degrees of bodily strength; and if there are cases, in which that which appears most eligible, may not suit the situation or circumstances of the patient, it cannot be difficult to contrive other means of giving motion, so as least to incommode, and yet to give the greatest relief. A very gentle and long-continued, or even incessant motion, may suit some cases better than any more violent and occasional agitation; and in this way, probably, it is, that seavoyages have sometimes been attended with remarkable advantage.

THE INQUIRER, No. XXI.

On the Deaf and Dumb.

F New speculations can be more interesting than those which relate to public institutions for the relief of the infirmities of mankind. The just and sound standard of utility is easily assigned. The first object of all charitable establishments, is to contribute to the welfare of society; therefore, the most essential claim to approbation and support, is, that they shall have a

salutary tendency. Foundling hospitals were proved, in a former inquiry, to be useless and injurious. Schools for teaching the deaf and dumb children of the poor, now solicit aid and support; and they seem to deserve encouragement, because the object of instruction is the generation of happiness; and by making individuals happy, who, by their misfortune, are almost struck off the roll of existence, the sum of happiness among the whole species is greatly increased. The instruction of the deaf and dumb, like the early structure of medicine, arose from the energies of individual genius; and by the like efforts of extraordinary intellects, it has been extended, and brought to its present degree of perfection. With respect to the methods of conveying instruction, in awakening the mind, in reading, writing, and arithmetic, it is impossible to describe them. They are admirably calculated to fulfil the intentions of their benevolent contrivers; and it would be to commit the same injustice towards the teachers, if any attempt were made to explain particular parts of their process, as towards an ingenious mechanic, by exhibiting detached parts of a complicated machine. The whole must be seen, in order to be thoroughly understood; we must go and live like the deaf and dumb, in order to learn how the deaf and dumb can be taught to live like men.

Deafness from birth, and consequently dumbness, is more frequent than is commonly imagined. In Eastern courts, it has been usual from time immemorial to retain a number of mutes. These are not only employed to amuse the monarch, but also to instruct his pages in an art, to us little known, of communicating every thing by signs, lest the sounds of their voices should disturb the sovereign. The mutes are also the secret instruments of his private vengeance.

In England the number of deaf and dumb children among the poor is considerable; for at the last election, in July 1810, at the asylum in London, there were seventy-eight candidates and only fifteen vacancies. There are now eighty children under tuition in the asylum. According to the reports of a similar institution at Vienna, which was established in 1779, there are always many candidates whenever a vacancy occurs. That institution is supported by an annual pension from the government; and forty-five boys are admitted on the foundation, besides day-scholars and boarders, whose circumstances enable them to pay for their instruction. It has been calculated, that in every million of souls in the German empire, (taking the estimate at twenty-five millions, which it was usually called before the French fraternization), one hundred are deaf and dumb: of these, only thirty in every hundred are supposed to be capable of being taught; the rest being too young, too cld, or too much diseased in other