54 OPERATIVE TECHNIQUE. 



140 times per minute, or by the intra-venous injection of warm 

 normal salt solution. Hobday recommends small doses of prussic 

 acid. Rosenberger believes that in man heart failure is due to 

 stimulation of the vagus, owing to irritation of the respiratory mucous 

 membrane by the chloroform vapour ; he recommends previously 

 painting the membrane with cocaine solution. The precaution is 

 unnecessary in horses. In proof of the irritation produced, however, 

 one may often note in well-bred horses certain symptoms of sore 

 throat, such as coughing, etc., during the few days next succeeding 

 the operation. Recovery usually occurs without treatment. 



Morphine and Chloroform. — When morphine is previously adminis- 

 tered the animals sometimes show considerably more excitement than 

 when chloroform alone is employed ; and as, generally speaking, the pre- 

 liminary use of morphine neither lessens the pre-anaesthetic period nor 

 decreases the amount of chloroform required, it is rather a drawback 

 than a help. Chloroform and ether mixtures present no advantages 

 over chloroform alone, except in cases of heart affection. 



Ether was the first and, in man, remains the favourite anaesthetic 

 It is administered in progressive doses from a sponge, tampon of tow, 

 or linen compress, or by means of Cox's or Carlisle's inhaler. An 

 ordinary deep leather bucket muzzle is a very good substitute, pro- 

 vided care is taken to prevent the liquid coming in contact with the 

 mucous membrane of the nostril. If necessary, inhalation is occasion- 

 ally stopped, and when surgical anaesthesia is complete the dose is 

 considerably reduced. During the whole time respiration and the 

 reflexes must be closely observed. 



The horse having been cast, anything which might impede respira- 

 tion, or compress the larynx, the lower portion of the neck, or the 

 thorax, is removed. If Cox's muzzle be employed the procedure is 

 precisely similar to that in giving chloroform ; otherwise a linen pad 

 about eight to ten inches square is placed over the nostrils, and ether 

 dropped on it in small quantities. The distance from the nostrils 

 regulates the rapidity of administration and the amount given. 



The mucous membrane of the upper respiratory passages being 

 irritable^ considerable excitement is at first produced ; the animal 

 neighs, struggles, and is sometimes very violent ; respiration and 

 circulation are accelerated. This stage sometimes lasts for ten minutes, 

 and is succeeded by that of surgical anaesthesia. 



The quantity of ether used is often considerable, from ten to twenty 

 fluid ounces, sometimes even more. Recovery is slower than after 

 chloroform. 



Though less dangerous than chloroform, ether is not, as some 



