HYPEfLEMlA OF THE LUNG. 143 



iiac action threatening life. The result here is astonishing. As SOOD 

 as the volume of the blood has become lessened, the pressure diminishes 

 in the arteries (as it depends upon two forces : first, the energy of the 

 cardiac contractions; second, the fulness of the cavities of the heart). 

 The patients often become able to breathe more freely, even during the 

 operation, the bloody foam which they were expectorating vanishes, 

 and life may be rescued from the greatest danger by aid of the phy- 

 sician. In cases like these, however, which have been called pulmo- 

 nary apoplexy (Jjungenschlagfluss)^ the danger arises with such light- 

 ning rapidity, that the physician usually arrives too late. 



Collateral fluxion, also, when it threatens life, requires venesection. 

 If, thereby, the force of the heart be diminished, the pressure, too, in 

 the arteries of the hyperaemic parts of the lung is also reduced, the 

 capillaries are less full, the transudation of serum, which was threatening, 

 or had already set in, does not occur or ceases ; and here, too, we often 

 see the patient breathe more freely and more deeply, while the blood is 

 yet flowing from the open vein. Since, however, in by far the greater 

 number of cases, the venesection has an unfavorable effect upon the 

 main disease by increasing the danger from exhaustion and impoverish- 

 ment of the blood, let us not be led astray by these striking instantaneous 

 results, so as to let blood without necessity, that is to say, unless life 

 itself be threatened ; but if, in the course of pneumonia, or pleuritis, or 

 recent pneumothorax, with intense dyspnoea, a moist rdle become audi- 

 ble, if the sputa become serous, etc., the danger is imminent; then 

 pay no regard to the small pulse, or rather look upon it as a new reason 

 for bleeding. The more recent the case, so much is collateral fluxion 

 the more easy of recognition, and so much the more surely can we rely 

 upon success. 



Should symptoms of oedema threaten in the course of disease of the 

 heart, immediate danger to life may demand a diminution of the volume 

 of the blood, and the relief consequent upon venesection usually satisfies 

 the expectation which has been entertained. In these cases, too, how- 

 ever, it is of the utmost importance to restrict blood-letting to the cases 

 oi the most urgent necessity. Persons with disease of the heart do not 

 bear repeated venesection well ; their blood, like that of emphysematous 

 persons, and for the same reasons, after long duration of the disease, is 

 poor in fibrin and albumen, and has great tendency to form serous 

 transudations. Venesection, by diminishing the volume of the blood, 

 readers it thinner ; the original mass is soon reestablished by absorption 

 of liquid from the tissues and from the intestines ; but the tendency to 

 dropsical transudation and even to cedema of the lung is aggravated in 

 this way. 



In the other forms of hyperaemia of the lung which we have de- 





