40 PATHOLOGY. 



drawn and pressed together. Wlien a true venous pulse exists 

 independent of heart disease, it is due to the veins filling when 

 the ventricles of the heart contract, and the sudden closing of 

 the auriculo-ventricular valves. It is supposed that there is 

 no actual retlux of blood, but a sudden arrestment of its flow 

 into the right ventricle. 



In some forms of heart disease the jugular pulse becomes a 

 diagnostic symptom. — (See Diseases of the Heart) 



SYMPTOMS CONNECTED "WITH THE EESPIRATOKY FUNCTIONS. 



The respiratory movements may be quickened, difficult or 

 laborious, wheezing, roaring, stertorous, spasmodic or convulsive, 

 irregular, slow, thoracic or abdominal; and be attended with 

 such signs as sneezing, coughing, sighing, or yawning. The 

 breath may be hot, as in pneumonia, fever, &c., and cool or cold, 

 as in cases of great prostration; fcetid, as in gangrene and 

 abscesses of the lungs, or in nasal gleet arising from diseased 

 bones or teeth. The matters discharged from the air passages 

 are also signs of great value, as blood, pus, mucus, or a mixture 

 of all of them. 



(a.) Quichencd hreathing. — Eapidity of the respiratory move- 

 ments, although present in many diseases, is easily produced by 

 any cause which accelerates the circulation of the blood, and is 

 generally proportioned to the rapidity of the circulation, and 

 the corresponding need of change in the blood. Thus, exercise, 

 which accelerates the circulation and changes of the blood, also 

 augments the respiratory movements. 



(&.) Difficulty of respiration (dyspnoea) is a prominent symptom 

 of disease, and may depend upon various causes. In inflamma- 

 tion of the lungs, or pleurisy, there are many circumstances in 

 operation wliich impede the respiratory movements — as pain, or 

 exudation into the substance of the lungs or cavity of the chest, 

 which mechanically resists the entrance of air into the lungs. 

 Diseases of the larynx or trachea, by diminishing their calibre, 

 are generally associated with extreme dyspnoea, and with sounds, 

 such as roaring or whisthng, which furnish pathognomonic signs 

 of the seat of the disease. 



Difficulty of breathing, when not accompanied by certain 

 sounds detectable by auscultation, if not sufficiently loud to be 



