CROUPOUS PNEUMONIA. 



191 



while after the patient has coughed, we ought at once to practise a 

 copious venesection, in order to reduce the mass of blood and to mod- 

 erate the collateral pressure. 



The third indication for bleeding arises upon the appearance of 

 symptoms of pressure upon the brain, not headache and delirium, but a 

 state of stupor or transient paralysis. 



Having determined, for one or other of the above reasons, to bleed, 

 the physician must not be misled by the fact that the pulse may be 

 small and feeble instead of full and vigorous. Among the practitioners 

 of the old school, " a small, repressed pulse " was always an indication 

 for blood-letting, and a great number of cases may be advanced to show 

 that the pulse often improves immediately after, or even during the 

 venesection, and indeed the rule obtained that when the physician was 

 in doubt as to whether the debility of the patient was genuine or false, 

 he must take notice whether the pulse became larger or smaller after 

 phlebotomy. The following is the reason why the pulse often grows 

 stronger and fuller during or immediately after a bleeding: Ceteris 

 paribus, the size and fulness of the pulse depend mainly upon the 

 ability of the heart to surmount the resistance opposed by the aorta. 

 If the functional vigor of the heart be reduced by the depressing influ- 

 ence which results from an immoderate increase of the animal heat, and 

 which, in some constitutions, is induced by a very moderate elevation of 

 the temperature of the body, the resistance opposed by the aorta remain- 

 ing unchanged meanwhile, the volume of blood propelled by the heart 

 is diminished and the pulse-wave is small. If, now, we reduce this 

 vascular tension by letting blood, we diminish the resistance of the aorta, 

 and enable the heart, although actually enfeebled, to propel an increased 

 volume of blood, and the pulse rises. True, we may fail in obtaining 

 this effect, when, as sometimes happens, the effect of venesection is 

 greatly to weaken the action of the heart, so that, although we diminish 

 the resistance, we also diminish the propulsive power. 



Digitalis has been extensively employed, and with great justice, in 

 the treatment of pneumonia. Like venesection, it is a febrifuge, lowers 

 the temperature, diminishes the frequence of the pulse, without exercis- 

 ing so weakening and depressing an effect upon the system as bleeding. 

 Its exhibition is indicated in pneumonia with a pulse of from one hun 

 dred to a hundred and twenty in frequence. With a less frequent pulse it 

 is not required. We usually combine an infusion of digitalis ( 3 j 3 ss. 

 to | vj) with the neutral salts of nitrate of potassa and soda. If the 

 latter have any influence upon the progress of the disease, it is only 

 apon the fever ; they have no antiphlogistic nor aplastic action. 



Next come the nauseants (antim. et pot. tart. gr. iv gr. vj to vj. 

 S. ^ ss every two hours) and ipecacuanha ; after these, quinine, veratrine. 



