There are two periods in the course of a croupous pneumonia in which blood-letting may be of service; first, in the early stage for the relief of pain and dyspnea, and second, in an advanced stage where there is engorgement of the right heart, also associated with intense dyspnea and general venous stasis.
No remedy is so efficient for the first object as blood-letting by the application of cut cups. Poultices, counter-irritation by the various measures commonly employed and even full doses of morphin hypodermically, are comparatively valueless as compared with wet cupping. Full doses of morphin produce temporary relief, but it passes away as soon as the effect of the drug wears off. No one who has not seen the happy result of such a bleeding can realize it. Venesection at the arm is less efficient, although it, too, relieves engorgement and diminishes pain and dyspnea. By no means
TYSON J. BLOOD-LETTING AND BLISTERING IN THE TREATMENT OF PNEUMONIA.. JAMA. 1902;XXXIX(20):1240–1241. doi:10.1001/jama.1902.52480460018001d