110 VASODILATORS 



3. To remove poisons, carbon monoxide, toxins, etc. It is of 

 very doubtful value in removing poisons since Levin, experimenting 

 with artificially introduced toxins, met with negative results. In 

 carbon monoxide poisoning,- blood-letting is a good procedure, pro- 

 vided it is followed by transfusion of blood, because the poison is in 

 the circulating blood. 



4. It has also been recommended as a curative measure in azo- 

 turia and as a prophylactic agent against parturient apoplexy of cat- 

 tle. It is also used in some sections in the beginning of fattening 

 animals. 



Venesection for the relief of marked local congestions was at one 

 time a favorite practice in human medicine, but not in veterinary 

 medicine. It was carried out by wet and dry cupping and leeches. 



In wet cupping a few small incisions were made close together in 

 the skin and a cup was applied over them. The suction was obtained 

 either by exhausting the air in the cup with a pump or by burning a 

 small amount of alcohol in it before it was applied. Only a small 

 amount of blood was obtained by this method. 



In dry cupping the same method was ptirsued, with the excep- 

 tion that no incisions were made and consequently only edema or 

 local congestion resulted. 



Leeches are small animals (Hirudo). They were placed upon 

 the desired part of the skin and allowed to remove a small amount 

 of blood. 



