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by the name of mucus. Examine in a microscope a little of the mucus, and you will find it made up of minute balls of transparent jelly with a granular aspect, technically called "exudation globules," "mucous globules," and "pus globules," floating quite free, and rolling over and over without any tendency to adhere together. They are young cells, or rather nuclei. They are the forms assumed by all liquid living material which under the influence of life is being transformed into a solid; they are infant tissue strangled in its birth. Instead of uniting into a continuous web to clothe with epithelium the surface of the membrane, they float off helpless from deficient vitality. The business of mucous membranes is to be covered with epithelium, not to throw off mucus; and when they are doing the latter they are so far forth in a state of diminished life.'

Or there may be a pharyngeal abscess, or a quinsy.

Disorders of motility and sensation will be discussed in Chapter X.

Beyond what the eye sees the nose makes its note when the oral cavity is examined.

Smell. The breath may be offensive from articles of food, as the onion, or garlic. Or decomposing food may be lodged amidst the teeth, or the teeth may be carious. Or there may be foul ulcers causing a smell. Or the metallic smell and taste of spongy gums, especially if due to mercury, may be present. Or the breath may tell of alcoholics recently taken; or that stale offensive breath of the drinker may testify to excess, however voluble and solemn the protest that such is not the case. Then the breath is habitually tainted with some persons, while in others it is only offensive in times of mental worry, or from indigestion; or maybe both combined when the breath is very disagreeable. The offensive breath of ozona, of gangrene of the lung, and foetid bronchitis-due to changes in the fluid in bronchiectasis-is known to all.

Having made the scrutiny of the tongue, the next thing to be observed is the respiration.

CHAPTER IV.

THE RESPIRATION.

THE respiration is worthy of study, as from it much may be learned. For instance, a patient is found with a loud mitral murmur, maybe regurgitant, or more probably stenotic. The loudness of the murmur carries with it no measure of the extent of the mischief; for that we have to fall back upon the physiological factor. What is the effect upon the respiration? That is the test! Does the patient breathe calmly; is the breathing accelerated, or distinctly embarrassed by effort, or not? If the patient breathe calmly when at rest, and there is no unwonted effect produced upon the respiration by effort, then there is but a slight lesion; if, indeed, there be any at all. The murmur may be entirely free from any sinister indications. The respiration may be normal, or it may be rapid, or it may be laboured.

Rapid Respiration.-The thorax of an ordinary man contains 250 cubic inches of air, known as 'the residual air.' In the act of respiration so much air is expired, and so much external air is inspired. The expired air contains more carbonic acid and less oxygen than the outside air. About twenty-six cubic inches of air are taken in, and given out, at each respiratory act. The normal rate of inspiration is about eighteen times per minute. There is a reservoir of air in the lungs by which the chemical interchanges can be carried on while the breath is held, as in diving. To hold the breath for one minute is no pleasant feat, but the Indian

pearl-diver can keep under water for a much longer period. Four minutes' immersion, and the person is dead, as a rule. The breath can be held so long as such interchanges can be carried on as fairly depurate the blood of its carbonic-acid gas; when the carbonic acid in the blood reaches a certain point, the respiratory centre flashes out an efferent message to the muscles of inspiration, and they respond. Men under torture which they knew was meant to be continued to death, have tried to kill themselves by holding the breath; but they have never succeeded. In the drowning person this involuntary respiration draws a quantity of water into the air-passages; and probably repeated respiratory acts, under the imperious dictates of the respiratory centre, fill the thorax with water till the body loses its buoyancy and sinks.

When from any reason the chemical interchanges are insufficient to depurate the blood of its carbonic acid, then the accumulation of this carbonic acid excites the respiratory centre, and violent respiratory efforts are made; until, by increased respiration, the residual air is sufficiently purified, so that the normal interchanges are regained. Thus after holding the breath a few deep inspirations are necessitated, after which all is once more calm. If the respiration be excited by a more prolonged demand, as a sharp run, then a longer time of exalted respiration is required for the normal state to be regained. Consequently, when the thoracic space is impaired, as by pneumonia or congestion of the lung, the diminished residual air requires more frequently 'the tidal air' to maintain its purity; and so the breathing is accelerated, or rapid.

Consequently accelerated respiration tells of excess of (1) blood; (2) connective-tissue; (3) water, in oedema of the lung or pleuritic effusion; (4) pus in empyema; (5) a morbid growth; (6) air in pneumothorax ; or (7) mucus in bronchial catarrh. (Air in emphysema involves rather another modification to be discussed shortly.) Of course the mere increase

of rapidity cannot indicate the nature of the cause of it. Excess of blood may be due to inflammation of the lungs ; to congestion of the lungs (localized); or to fulness of the pulmonic circulation from a mitral lesion. Excess of connective-tissue may occur as fibrosis, or as pulmonary tuberculosis. Excess of water is found in edema of lungs, or effusion into the pleural cavities; or maybe into the pericardium. Excess of pus is usually found in empyema, but an abscess might cause it. A morbid growth, as a tumour, or a cancer, will accelerate the respiration in proportion as its size impinges upon the thoracic space. Air elsewhere than in the air-passages will produce the same result of diminution of the thoracic space. Catarrh of the bronchial lining membrane will also accelerate the respiration by diminishing the lumen of the air-tubes; also blocking some of them temporarily.

Careful estimation of the rate of respiration will often materially aid the observer to read the physical signs aright. Especially is this the case when the peccant matter is either disseminated over the lungs, as in general fibrosis, or the neoplasm is too deep-seated to affect the percussion-note; or there are internal cavities, or bronchial dilatations; or there is a large accumulation of mucus in the air-passages. Indeed, the rapidity of the respiration will tell him more exactly the amount of the disturbing cause than will percussion or auscultation at times. He must, however, compare the ratio of the respiration to the pulse, which is normally 1 to 4; the first being 18 and the latter 72. It is well, indeed, to do this habitually; and if such practice obtained many an error would be avoided. If the pulse and the respiration both be high, then there is either some febrile condition or nervous excitement; something which affects both alike, and probably the temperature too. (But of this last anon.) Such use of the watch will usually tell how a case is going on. If the breathing becomes accelerated out of proportion to the pulse rate, then it is high time to

look for something; and 'something' will usually be found. Say the patient is in bed with mitral disease, for instance, and the respiration rises: then there is some special cause of diminution of the thoracic space, which will probably be found to be congestion of the bases of the lung, mostly at the back-the dependent part. If there be dropsy present, it may be oedema. The use of the watch will often put the medical man on his guard, and make him examine the chest when otherwise there might appear to be no especial call to do so. Also it will often relieve him, and still more the patient, from examination which is superfluous, troublesome, and yet negative of result. It may happen that a fidgety patient (very likely a medical man, who makes a very trying patient as a rule) may like a physical examination, and be dissatisfied without it; but there are others who resent being disturbed without sufficient reason. To take the ratio of the respiration and the pulse will often, indeed commonly, tell whether a physical examination be required; or may safely be dispensed with. If the respiration has been accelerated and falls, then it is fairly clear the infringement upon the thoracic space is diminishing.

The rapid breathing may be shallow, with little respiratory movement; this is found with nervous states, and in some forms of phthisis. Usually in the latter case there is no great impairment of the thoracic space demanding accelerated breathing; it is rather nervous than of organic origin in many instances, even when some consolidation is present.

Deep Respiration. This is linked with other conditions within the thorax. In emphysema the patient will be seen fixing the shoulders, so as to enable the accessory muscles of inspiration to act more efficiently; and then the sternomastoid muscles will be seen to stand out like cords, rhythmically as each inspiration is accomplished. If the patient be lying in bed, the character of the respiration is very instructive. The muscles at the top of the thoracic case are seen to contract powerfully, while the abdomen rises.

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