Acute Croupous Pneumonia. Pneumonitis in the Horse. 229 



of cases treated by excessive bleeding, and the lower fatality in 

 pneumonias treated without phlebotomy on the expectant (let 

 alone) plan of Dietl or the stimulating method of Todd, Bennett 

 and others, served to hasten its abandonment. Yet in bloodletting 

 we have an instrument for good or evil which is not to be judged 

 on slight evidence. The mere lessening of the blood pressure is 

 to be little considered, as it requires the abstraction of nearly one- 

 third of the entire mass of blood to visibly affect this. The vas- 

 cular walls at once adapt themselves to the lessened amount. Nor 

 is the mere lessening of the volume a vital point. After moderate 

 bleeding this is made up in a few hours : after severe bleeding in 

 24 to /l8 hours. The loss of adult red globules is more lasting. 

 Bleeding to the extent of one per cent, of the body weight may 

 have the number restored in seven days. The young red globules 

 though rapidly produced have individually less haemoglobin, and 

 they can convey less oxygen to the tissues. This should mean 

 less oxidation, less heat, less waste, less urea, uric acid, hippuric 

 acid and other poisonous products in the tissues. Yet Baur says 

 that in anaemia there is a greater metabolism of proteids and more 

 excretion of urea. How easy it is to blunder in looking from one 

 single point of view. Again after bleeding there is a great relative 

 increase of the various forms of white blood globules, most of 

 them young and therefore with somewhat altered functions. The 

 paucity of red globules and excess of white are brought about by 

 the pneumonia and independently of bleeding, so that it is difficult 

 to say whether the phlebotomist is enhancing an evil, or helping 

 a natural therapeusis. It seems hopeless to estimate the effects 

 of these and other changes in the blood after bleeding, upon th© 

 metabolic processes of nutrition, secretion and sanguification, 

 This digression has not been made to ellucidate the results or the- 

 modus operandi of bleeding, but rather to illustrate the complexity- 

 of the problem involved and to warn against broad ^nd unwar- 

 ranted generalizations from insufficient premises. 



Even to-day practitioners of the soundest judgment meet with a 

 limited number of cases in which they resort to bleeding with ad- 

 vantage. These occur mainly in strong, robus^ constitutions, in 

 individuals accustomed to an invigorating, open air life, liberal^ 

 diet and abundant exercise. Ev^en in these this measure is chiefly - 

 resorted to, to relieve an acute pulmouar-y cppgestipn with ^, 



