moval of the affection, under favourable circumstances the patient will be thoroughly restored to health. But if, as too often happens, valuable time is lost, and the condition of the patient is overlooked; or, if he is looked upon and treated as a nervous dyspeptic or hypochondriac, the disease will most assuredly advance. The expectoration, instead of being white and transparent, will become mixed with white curdy matter. It will assume a pale yellow colour, and occasionally appear streaked with blood. The cough will become more severe and troublesome, and the night sweats will be constant and profuse.

At this stage of the disease, the breathing is more hurried; the nervous excitement more constant, and the pulse more frequent; the strength fails; the muscles become flabby and lax, and considerable emaciation ensues. The patient is little disposed to any exertion or exercise, and feels exhausted by the slightest effort. Nervous pains, as they are called, are felt in different parts of the chest; or sudden and violent pains which instantly stop the breath, known by the name of "stitch in the side" frequently attack and greatly distress the sufferer. This is often produced by tubercles situated in the substance of the lung. Such persons become highly sensitive and nervous; the least disturbance or excitement, especially if sudden and unexpected, produces the greatest agitation. Under such circumstances there is frequently copious expectoration mixed with blood; and large quantities of blood are often coughed up. If one lung only be affected, or one much more severely than the other, the movements of the chest, if exposed to view, will at once disclose to the experienced eye the lung which is most diseased, and the side of the chest on which there is the greatest amount of mischief. On the

healthy side the ribs will rise and fall regularly during respiration; whereas on the more diseased side, they will be comparatively motionless.

But if the attention of the practitioner is directed to the removal of the effects, instead of the causes; if he looks merely to allaying the cough, and combating secondary affections, the opportunity of re-establishing the health will be absolutely lost. When what is termed the third stage of pulmonary consumption is once fully established-indicated by the night sweats becoming profuse; the bodily strength fast declining; continued and exhausting purging; copious perspiration; incessant hacking cough; constant pain or tightness of the chest, attended with shortness of breath-all hope of recovery is at an end. No one possessed of even the most limited experience, could hold out the slightest expectation of a cure. All that can be done is to alleviate the pain, and soften down, as far as practicable, the patient's suffering. The lungs in this stage frequently contain cavities, and pectoriloquy is audible in them both; and they are studded with tubercles, as shewn in fig. 6.

In the treatment of this class of nervous disorders, in which a principal feature is the implication of the lungs, it is absolutely necessary to search out the cause and remove it. When they arise-as too often hap

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pens in a dense metropolis like London-from an impure and vitiated atmosphere, we may as well expect, as Combe very appropriately remarks, a fire to burn without air, or a fish to live out of water,' as a patient, under such circumstances, to recover, while the cause remains in uncontrolled and active operation. Yet seldom do we observe these points attended to in practice.

When it was the custom to bring up pauper infants in the London Workhouses, where the air was contaminated and extremely impure; of two thousand eight hundred of the children annually received into these establishments, two thousand six hundred and ninety died within the year;-a fatality almost incredible. This great and

extraordinary mortality at last attracted the notice of parliament, and an act was passed, making it compulsory upon the parochial authorities to bring up the children in the country; and in consequence of this salutary enactment and its provisions, the mortality fell from 2600 to only 450 in the year.* Facts like these ought to be sufficient to impress the mind with the absolute necessity of securing a regular and sufficient supply of pure fresh air, as one of the principal and most powerful agents in the treatment of these affections; and that we should not, in spite of such evidence, trust to the influence of medicine alon

Let it ever be remembered, that from twenty to thirty cubic inches of air enter the lungs at each inspiration, and that the average number of respirations in health may be considered as varying between fourteen and twenty in the minute. With this large consumption, there is effected at the same time a considerable vitiation of the contiguous or surrounding air; which takes place to a greater degree *Combe's Physiology p. 67.

when the lungs are diseased, and the number of inspirations in a given time are increased.

The unprofessional reader will be surprised to learn that a single individual in health requires from sixty to one hundred cubic inches of oxygen per minute, to effect the decarbonization of the blood and fit it for the purposes of life. It must therefore be of the greatest importance, more especially during disease, that the atmosphere, so essential not only to health, but even to life, be pure and unadulterated.

Pure atmospheric air, consists of a mixture of oxygen and nitrogen, in the proportions by measure of twentyone parts of the former to seventy-nine of the latter; to which may be added a mere trace of carbonic acid gas. But in ill-ventilated apartments, or crowded rooms, the relative amount of carbonic acid gas is greatly increased. Animal respiration, is itself a fruitful cause of the deterioration of the air. The inspired air, when emitted from the lungs, is found to be altered in composition and properties. The bulk of the air, emitted during expiration, very nearly equals that of the air taken into the lungs during inspiration; but on comparing the analysis of the air before inspiration with that of the air when expired, we find a marked and important alteration.

It has been already stated that pure atmospheric air consists of twenty-one parts by measure of oxygen, and seventy-nine of nitrogen. When emitted from the lungs after expiration, it is found to have a very considerable portion of its oxygen converted into, and replaced by an equal volume of carbonic acid gas; nearly ths of the oxygen disappear and are replaced by their equivalent of carbonic acid gas. This is the effect or change wrought in the air by one single respiration. If the same air continues to be breathed again and again, the

quantity of oxygen is still farther reduced, and the amount of carbonic acid is increased at each succeeding expiration. If the amount of this gas be permitted to reach to from eight to ten per cent, the air, so contaminated, will be no longer fit for the support of animal life; and persons breathing it will die with all the symptoms of narcotic poisoning. This is what actually occurred in the black hole at Calcutta. Too many persons were crowded and huddled together in a small close ill-ventilated apartment, and the following morning told the melancholy tale. On the guard's opening the doors, it was found that by far the greater number had perished during the night.

The lungs, in health, take in nearly eighteen pints of air each minute, and in the same space eight pints of blood are oxygenated, purified and fitted for the purposes of circulation and the support of animal life. In cases of disease of the lungs, we cannot too strongly enforce the necessity of taking especial care that the atmosphere which is breathed be as pure as possible, both night and day. If it is deteriorated, the lungs will be irritated. The apartment should be well ventilated, and the bed should be without curtains.

It is quite impossible to cure a patient suffering from disease of the lungs by any treatment whatever, if he be permitted to continue breathing an impure and vitiated atmosphere. We may as well expect to draw blood from marble, or sustenance from stones, as to eradicate consumption, while these principles of physiology and pathology are disregarded.

We learn from the researches of Farre, that in the year eighteen hundred and thirty-eight, fifty-nine thousand and twenty-five persons died of consumption in Great Britain alone; and it has been inferred that ninety thousand persons annually fall victims to this scourge, throughout the United Kingdom.