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person may have a violent inflammation of the lungs, and yet 

 be entirely without pain, have no difficulty of breathing, 

 and only a slight cough. And, under these circumstances, 

 the pulse, the skin, and the tongue, are the only remaining 

 fallacious signs to indicate not only the seat, but the nature 

 of the complaint ; and it may be truly said, that a physician 

 who has a knowledge of these signs only, is as much liable to 

 be in error respecting diseases of the chest, as a person who 

 examines in a soil only the colour, consistence, and the 

 vegetation, for indications of its fertility. 



Laennec, however, by the discovery of other physical signs, 

 has done for medicine, what Chemistry has for Agriculture, 

 added greater precision to our knowledge. He found by the 

 aid of percussion and auscultation, that five cases out of seven, 

 present in pneumonia in the first stage of invasion : 1 . A re- 

 markable feebleness of breathing. 2. That in nearly all cases 

 under fifty years of age, during the second or inflammatory 

 stage, there is a remarkable crackling in the lung, (a crepitant 

 rhonchus,) resembling salt thrown into the fire, and perfectly 

 diagnostic of the complaint. 3. That in the third stage, the 

 respiration is bronchial throughout the lung, accompanied by 

 dulness upon percussing the walls of the chest. Then the 

 labours of pathologists were brought to bear upon this subject, 

 and just as geology is able to explain why variations in the 

 colour, consistence, and vegetation of soils do take place, 

 as well as most of the chemical and mechanical differences ; 

 so the anatomy of diseased parts (pathological anatomy) has 

 been made subservient to the explanation of all the symptoms 

 attending disease, and has become the very basis of an en- 

 lightened view of therapeutics. It informs us in the case 

 before us, that in the first stage of inflammation, the blood 

 vessels are loaded with an inordinate quantity of blood, the 

 lung consequently congested and tumefied, and consequently 

 the first physical sign of feebleness of respiration is explained; 



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