The coexistence of delirium is not to be regarded as a separate diaease, but as one of the phenomena attending on severe pneumonia. It is of much im portance in treatment, and when appearing early may lead to a suspicion that fever of the continued. type exists along with the pneumonia, but does not necessarily imply this condition, as the altered character of the blood is suffi cient to account for the cerebral disturbance.
§ 4. Pleurisy.—In its proper sense, one of the acute inflamma tions of the chest, it commonly seta in with pretty smart fever and stitch in the side. We find from the history, perhaps, that there has been some exposure to cold, and that the attack com menced with rigor. The ordinary symptoms of inflammatory fever are present, with considerable dyspncea, manifested in quick, shallow breathing, with little movement of the ribs ; the patient especially abstains from taking a deep breath, or making any attempt to cough, because the friction of the inflamed surfaces, caused by either act, excites or aggravates the sensation of pain • the character of the pain is sharp and darting, and it is referreci to a spot just below the nipple, on the affected side. The face is seldom flushed, and the color is not dusky, because there is no obstruction to the oxygenation of the blood as it passes through the lung. In the early stage the patient seldom lies on the af fected side, as he does at a more advanced period—probably he complains that such a posture increases his sufferings ; at this time, too, the physical signs are few and indistinct. They con sist simply of impaired movement of the ribs over the whole side, or more particularly over that part where the inflammation has commenced. The breath-sound is more or leas suppressed or jerking, in consequence of the pain attendant on full and perfect mspiration, while the expiration appears .prolonged- and this suppression as it partially extends to the healthy side, tends to diminish the contrast between the two. The voice-sound is ge nerally exaggerated at an early period over the seat of inflamma tory action. Friction is sometimes heard very soon aft.er the dia ease has commenced, and then there is always attendant dulness on percussion. Here the disease may stop, and no effusion of fluid occur. Occasionally in cachectic states the inflammatory fever proves fatal, with delirium and copious effusion of lymph, without any exudation of serum at all; in such cases the friction sound may be very persistent and very grating, and heard over a large surface, imitating closely the crepitation of extensive low pneumonia. These, however, are exceptional cases; the friction is generally transient, and the patient either recovers rapidly, or the inflammation goes on to the effusion of fluid.
The duration of the disease, however, may be very prolonged ; and when the case first comes under observation, this circumstance alone does not exclude the possibility of pleurisy. It may hap pen that the early stage is scarcely marked, that there has been no pain, no febrile disturbance, nothing to denote what is going on, till dyspncea appears as the result of the pleura having become full of serum. The patient may have had pain in the affected side for weeks or months from some other cause—dyspepsia for instance; and it then becomes quite impossible to fix the date of the commencement of pleurisy.
In the further progress of the case, dyspncea becomes a more constant feature, ordinary breathing is interfered with ; pain, if it have existed, subsides ; the face is apt to be dusky or discolored ; and the patient very often seeks an erect posture, inclining to the affected side. Dulness on percussion is very manifest; at the base the sound is especially dead, inelastic, and resistant : higher up, while it acquires some degree of elasticity the resonance nowhere presents the character of health. The breath-sound is absent at the base; above it is blowing, and the expiration prolonged. The only exception to this rule in simple pleurisy, arises from some part of the lung being tied down by old adhesion; but as it can not be so on all sides without its being so generally adherent that there is no room for fluid, the characters enumerated will be traceable somewhere or other on the affected side. Towards the middle part of the chest, generally about the lower angle or spine of the scapula, the quivering or shakiness of the voice-sound, called Legophony, is perceptible. When the pleura becomes quite fall, the intercostal spaces bulge ; the dulness passes the median line in consequence of the mediastinum being pushed over, and along with it the heart is displaced : this circumstance is to be observed earlier, and is always more palpable when the fluid is on the left side. The breath-sound is almost entirely suppressed : now and then the sound of friction may be caught, its position depending on the amount of fluid, the laws of gravitation, and the circumstance of air entering at all into the lung, and leading to relative position between it and the parietes. After pleurisy has some time, the recurrence of rigor, followed by copious sweating, generally indicates the conversion' of the serous effusion into pus; empyema as it is called.