Sometimes the expectoration is offensive, and occasionally it is so to a very high degree. The cause of this is no doubt the admixture of disintegrated lung tissue ; but while occasionally the process is rapid and gangrenous, with black and gramous sputa. more frequently it is merely fetid pus, the result of rapid and unhealthy suppuration ; both are generally confounded together, as gangrene, but the condition of fetid abscess ought to be distinguished from it.
In the observation of many of these points it is often necessary to wait until anything like flurry or nervous excitement have passed, or at least to correct the observations made on first seeing the patient by others at the end of the visit. and not unfrequotly to abstract the patient's attention from the particular syinptom which is for the moment the subject of observation.
§ 2. Physical Signs.—It is not necessary in the present day to study much in detail those, the general symptoms of disease of the chest; but there was a time when, to the correct interpreta tion of such vague and uncertain signs, the attention of the phy sician was confined. In our own day diagnosis has made great advance in consequence of the light thrown upon this class of diseases by the practice of auscultation and percussion, and the error to which we are liable is that of overlooking the general symptoms, and being satisfied with the physical signs; and the deductions from these two sources of information, if considered apart, may be wholly at variance with each other. The student should therefore make careful note of all that he can acquire of the history and the general indications before he proceeds to the minute examination of the organs of circulation and respiration, in order that he may correct the inferences he may be disposed to draw from this source by observations made before his judg ment had received any bias from the indications it affords.
The facts which we have to study consist of the relative move ments of the different parts of the chest ; the proportion and position of solids or fluids and air as determined by percussion ; and the sounds produced, whether normally or abnormally, by the movement of air, or air and fluid together, in the lungs, and of blood and solid structures in the heart and great vessels • and in connection with these, the condition of parts as sound-conduct ing, or sound-generating media. To describe these sounds in
such a way as to be intelligible to one who has never heard them is impossible, and to describe them to one who has, is unnecessary. I would only remark that any student who will take the trouble of examining the chest of every patient, will learn to distinguish the sounds of health and disease in a very short time ; while those who merely listen to such' cases as are pointed out to them as instances of certain diseases, or of certain unusual sounds, will never have an adequate notion of the value of auscultation. It is absolutely necessary, in order to make any advance at all, that the natural respiratory sound, and the natural first and second sounds of the heart, be known and understood ; and the student who is anxious to learn them will never come away satisfied with having heard nothing. It too often happens with the learner, that when some peculiar circumstance is pointed out to him in the wards, he is too hurried or too nervous to catch the sound described : in all such cases, my advice to him would be to re move his ear to some other part of the chest where he knows the natural sounds are most easily to be heard, and gradually and patiently to approach the point to which his attention was first called ; a sound once heard becomes louder and more distinct, as it becomes more familiar to the ear by prolonged attention: if he then take the earliest opportunity of comparing what be has just beard with that which is to be found in the same spot in a patient not laboring under disease of the chest, he will best know whether he have learned anything that may be of value to him afterwards.
a. External Appearances.—If we were to follow strictly the order in which the various organs are placed in the Table of Diseases, we should commence with diseases of the heart and bloodvessels, which have been placed before those of the respira tory organs, because they have less of a local character ; the circulatory apparatus being distributed, like the nerves, to every part of the body. With reference to diagnosis, there seems an advantage in pursuing a different course ; because diseases of the heart are more readily understood when the phenomena connected with the lungs, which occupy so much more space in the thoracic cavity, have been previously explained.