246 PRINCIPLES OF VETERINARY SURGERY 



prior to the operation, is to be avoided. Debilitated sub- 

 jects, either from over-work^ bad hygiene or from disease, 

 are never vi^elcome surgical cases. Structural alterations 

 of the heart, — although these can seldom be diagnosed, — 

 are generally considered as contra-indications. It is, how- 

 ever, doubtful whether there is more danger with than 

 without, the anaesthetic in these cases. The writer has had 

 a death from rupture of the coronary artery caused by se- 

 vere straining during a quittor operation, that would cer- 

 tainly have been avoided had an anaesthetic been admin- 

 istered. Operations on the upper air passages should 

 generally be performed without general anaesthesia, on ac- 

 count of the greater danger of aspirating blood, saliva and 

 putrid matter into the lungs. Among these are trephining 

 the skull for nasal catarrh, ablation of nasal tumors, opera- 

 tions on the guttural pouches and the reposition of com- 

 minuted fractures of the facial bones. 



General anaesthesia is contra-indicated, also, when the 

 alimentary canal is overloaded, or even normally full of 

 aliment. In this instance the respirations are mechanically 

 obstructed, and hence rather susceptible to arrest from the 

 depressing influence of the anaesthetic. 



Disease of the lungs (heaves), diseases of the pleura 

 (pleural adhesions) and diseases of the large blood-vessels 

 (aneurism) are ever prone to prove the undoing of an 

 anaesthetized patient. Like the disease of the heart the 

 latter are found at the post-mortem only. 



PARTIAL GENERAL ANAESTHESIA.— There are 

 certain conditions encountered in veterinary surgery in 

 which complete general anaesthesia is neither advisable nor 

 practical, and which can be coped with by blunting the sen- 

 sibility with narcotics. In the dog, the hypodermic injec- 

 tions of morphia, already referred to, produce a state of 

 partial anaesthesia which renders possible many of the sur- 



