a harsh, creaking sound is heard, the vibration occasioning which may sometimes also be appreciable on palpation-the so-called friction-sound or rub. The breathing is shallow, feeble and rapid; the movements of the affected side being restrained in the greater degree in order to mitigate the pain.

In the second stage, or stage of effusion, serum in variable quantity, possibly mixed with blood, is poured out into the pleural cavity. The corresponding lung is pushed upward and backward, and the heart, liver, spleen and diaphragm may be displaced. One side of the chest appears larger than the other, and the interspaces corresponding to the situation of the effusion are abnormally prominent. The cardiac impulse is visibly displaced. The respiratory excursion is limited. Below the upper level of the fluid the percussion-note is flat; above, it is subtympanitic. Through the effusion the breath-sounds are heard feebly and indistinctly; the voice-vibrations are not transmitted to the palpating hand; nor, as a rule, to the auscultating ear, though exceptionally bronchophony may exist. To the ear applied to the chest above the level of the fluid the voice may be transmitted with a peculiar bleating quality-constituting egophony.

In the third stage, the effusion has been absorbed and the apposed layers of pleura again come in contact. The frictionsound of the first stage returns. Ultimately the pleura may be restored to its original condition or its apposed surfaces may become adherent and thickened, giving rise to retraction of the chest and percussion-dulness.

How does acute pleurisy differ from croupous pneumonia?

Pleurisy usually accompanies pneumonia. The signs of the former, however, should not be permitted to obscure the existence of the latter. Neither the local nor the general symptoms of pleurisy are so profound as those of pneumonia. While pneumonia may then present the symptoms of pleurisy, pleurisy does not present the blood-streaked expectoration, the crepitant râle, the blowing breathing, the deficiency of the chlorides in the urine, or the critical termination of pneumonia.

The percussion-note of pneumonia is dull; that of pleurisy, when an effusion exists, is flat. The dulness of pneumonia is

usually over a lower lobe; that of pleurisy is universally at the base. In pleurisy, the breath-sounds are heard feebly, or not at all, through the effusion; in pneumonia the breathing is bronchial. Vocal resonance and fremitus are increased in pneumonia; they are diminished or absent in pleural effusion ; above the fluid, however, a bleating sound is transmitted to the auscultating ear. Simple, uncomplicated pneumonia is unattended with friction-sounds and occasions no displacement of adjacent viscera.

How are intercostal neuralgia and acute pleurisy to be differentiated?

The pain of intercostal neuralgia may simulate that of acute pleurisy, and give rise to rapid, shallow, feeble respiratory movements. Intercostal neuralgia is paroxysmal and unattended with friction-sound, dulness on percussion or fever; it occurs in anemic individuals with neurotic tendencies, and may be attended with a unilateral herpetic eruption in the course of the nerve affected. In addition there are a number of tender points.

How are a pleuritic effusion and an hydatid cyst of the liver to be differentiated?

When an hydatid cyst of the liver attains proportions sufficient to give rise to definite physical phenomena, these will appear in a region beyond that in which the signs of a pleuritic effusion on the right side are found. The history of an acute attack is wanting, while it is present in pleuritic effusion. Neither in case of pleuritic effusion, nor in case of hydatid of the liver, is the percussion-dulness confined to the right hypochondrium; in the one it extends rather upwards, in the other downwards; in the latter it is associated with fluctuation. In a case of hydatid cyst it may by percussion be possible to elicit the characteristic thrill or fremitus. In a case of pleuritic effusion the breath-sounds and the vibrations of the voice are feebly transmitted; breath-sounds, vocal resonance, and fremitus are unaltered in hydatid cyst of the liver. Egophony is characteristic of the presence of fluid in the pleura; it is thus not present in case of hydatid cyst of the liver. Exploratory

puncture may determine the presence of hydatid hooklets, the detection of which places the diagnosis beyond doubt.

How are a pleuritic effusion and abscess of the liver to be differentiated?

Symptoms of respiratory interference are naturally less conspicuous in case of abscess of the liver than in case of pleuritic effusion. Hepatic abscess may occasion tumefaction in the right hypochondrium; pleural effusion renders the chest asymmetrical from unilateral bulging. Pleuritic effusion impairs the transmission of the breath-sounds and of the vibrations of the voice, which is unaltered by an hepatic abscess. Egophony may be elicited in case of pleuritic effusion, but not in case of hepatic abscess. Rigors commonly attend an abscess of the liver; they only take place in cases of pleuritic effusion when suppuration has occurred. In case of hepatic abscess, there is usually a history of gallstone, of ulceration of the bowel or of pyemia ; in case of pleuritic effusion, there is a history of an acute attack of pleurisy. Hepatic abscess and perihepatitis may, however, give rise to pleural effusion by extension.

How are pleuritic effusion and abscess of the spleen to be differentiated?

Abscess of the spleen is most common as a manifestation of pyemia; pleuritic effusion is a sequel of an acute pleurisy. The symptoms of respiratory derangement, a necessary part of pleuritic effusion, are subordinate in case of splenic abscess. Repeated rigors occur in abscess of the spleen; rigors occur in case of empyema, but not when the effusion is not purulent. Egophony may be developed when fluid is present in the pleural cavity, but not in case of splenic abscess.

How is an intra-thoracic tumor to be distinguished from chronic pleurisy?

Tumors in the chest may arise from the pleura or from the lung; they may develop in the mediastinum ; or they may be aneurismal. Malignant tumors are secondary to growths elsewhere-an element in diagnosis. They give rise to circumscribed areas of dulness on percussion, not necessarily limited to one side; to enfeebled breathing and perhaps friction-sounds;

in their physical signs, they more closely resemble encysted pleurisy than ordinary chronic pleurisy. When actually complicated by pleurisy, the diagnosis may not be possible. Aneurisms occur in the course of the aorta and large vessels, and, in addition to the evidences of tumor, are accompanied by thrill, bruit and pulsation.

How are a pleuritic effusion and hydrothorax to be differentiated?

Hydrothorax occurs as a result of cardiac insufficiency or as a part of a general dropsy, from nephritis for instance.

In contradistinction from pleuritic effusion, the effusion of hydrothorax is bilateral. In the former there has been an antecedent pleurisy; in the latter there are other evidences of cardiac failure or of a general dropsy.

How is a pericardial effusion to be distinguished from a pleural effusion?

A pericardial effusion occurs under circumstances similar to those that give rise to a pleural effusion-as a result of inflammation or as a part of a general dropsy. The position and outline of the percussion-dulness to which a pericardial effusion gives rise, however, are entirely different from what is found in a case of pleural effusion; nor are the breath-sounds notably interfered with, while the circulation is embarrassed and the heart-sounds are almost obliterated at the cardiac apex.

Acute Bronchitis.

What are the symptoms of acute bronchitis?

Acute bronchitis results from exposure to cold, the inhalation of irritating fumes, or as a secondary disorder in the course of fevers, rheumatism or heart-disease. There is irritative cough, and, at first, scanty mucous expectoration, which subsequently becomes more copious and muco-purulent; slight elevation of temperature; increased frequency of respiration; some dyspnea; retro-sternal pain, and mild constitutional symptoms.

What are the physical signs of acute bronchitis?

The chest is not deformed and expands well. The percussionresonance is vesicular. The breathing is harsh at first; dry râles,

sonorous and sibilant, are heard; subsequently large and small moist râles. Vocal resonance and fremitus are not perceptibly

altered.

How does acute bronchitis differ from acute miliary tuberculosis?

In acute miliary tuberculosis the dyspnea is greater, the temperature is higher, with greater oscillations, the breathing is more rapid, and the symptoms are more profound than in acute bronchitis. The further progress of the case clears up any possible doubt. Recovery from acute bronchitis is the invariable rule. Pulmonary consolidation and softening, percussion-dulness and fine moist râles, emaciation, hectic fever, gradual failure of the vital powers and ultimately death mark the usuał course of acute miliary tuberculosis.

Chronic Bronchitis.

What are the symptoms of chronic bronchitis?

Chronic bronchitis is usually a result of repeated attacks of acute bronchitis; it may manifest itself as a special susceptibility to acute bronchitis; at first it appears as a winter cough, subsequently becoming continuous. It may obstinately resist treatment; it is attended with a good deal of cough, copious muco-purulent expectoration, marked shortness of breath, and may in time give rise to emphysema, or to bronchiectasis. It is often attended with loss of flesh and strength.

What are the physical signs of chronic bronchitis?

If emphysema coexists the chest may be enlarged; otherwise it is not abnormal in size or form; the respiratory excursion is somewhat diminished; the percussion-resonance is little or not at all impaired; the breathing is harsh and may be feeble, the bronchial element preponderating. Coarse râles, moist and dry, are heard at all parts of the chest. Vocal fremitus and resonance are rather increased.