STETHOSCOPY. 189 



STETHOSCOPT. 



Bt SAMUEL HAET, M. D. 



ONE fifth of the adult population of Christendom is suffering from 

 chest or thoracic diseases of a degree varying from the insig- 

 nificant to the most grave ; while another fifth is living in constant 

 fear of being or becoming their victims. 



In fact, diseases of the lungs and heart far exceed those of any- 

 other class in prevalence and fatality — consumption, so called, causing 

 one fourth of the mortality between the ages of seventeen and thirty- 

 five years — while diseases of the heart are of well-known formidable 

 eharacter, and raise the proportion of thoracic or pectoral diseases to 

 a surprising ratio. 



The study of this subject, as regards the causes and preventives, 

 the symptoms and cure, has received the diligent attention of scientists 

 and sanitarians as well as of physicians. 



Leaving to the physician his subject in its multiple and exhaustless 

 forms, I propose in this paper to give some account of the practical 

 diagnosis, or methods of determining the nature, exact locality, and 

 extent of thoracic disease, by means of stethoscopy, or the jihysical 

 exploration of the chest. 



The thorax incloses the essentially vital organs — the lungs with 

 their pleurae, or delicate membranous coverings, and the heart with 

 its pericardium and great blood-vessels. These, actuated through their 

 system of nerve-filaments, give the rhythmic heavings of respiration 

 and the throb and pulses of the blood-circulation. 



Although so admirably guarded against harm by the strong and 

 elastic chest-walls, and against all inimical approach by that ever-vigi- 

 lant sentinel, the epiglottis, they are, from the very nature of their 

 functions, pre-eminently subject to danger from without as well as 

 from within. The delicate mechanism of living lung-tissue can not be 

 subjected to direct observation ; the minute cells for containing air 

 would be crushed by air admitted from without, and the heart ar- 

 rested for a moment for inspection would never beat again ; yet the 

 vital operations of these organs are well understood and their morbid 

 conditions can be read almost as if exposed to view. 



On firmly applying the ear to the walls of the chest of a person in 

 health, certain sounds can be heard, varying in loudness and clearness 

 with the quarter of the chest at which the ear is applied, and with the 

 age or individual peculiarity of the person examined, or his state of 

 action or repose. The double sound of the heart, embracing what are 

 known as the first and second sounds, is heard distinctly : the former 

 caused by the strong muscular contractions of the ventricles, mainly 

 the left, whose function it is to distribute the blood to the system. 



