PRINCIPLES OF VETERINARY SURGERY 227 



is shown that while all protoplasm may be anaesthetized, 

 the brain cell is more sensible than the nerve, and the nerve 

 more sensible than the muscle, and the muscle more than 

 the tendon, etc., down the scale. In this same manner it is 

 found that man is more sensible than the horse, the horse 

 more sensible than the ox, the ox more sensible than birds, 

 birds more sensible than the frog, and finally the frog is 

 more sensible than the vegetable. These facts explain, 

 beyond reasonable doubt, the phenomena following the in- 

 halation of the highly volatile anaesthetic, that can be 

 rapidly introduced into the blood and finally as rapidly 

 eliminated or destroyed. The nerve cells of the brain and 

 spinal cord being very highly sensitive to its action are 

 promptly dehydrated (altered, disorganized, etc.) as the 

 molecules of inhaled vapor are carried to them, the result 

 being the state known as ansesthesia. Some authors have 

 insisted that these theories cannot be accepted entirely un- 

 challenged until an explanation is forthcoming as to why 

 the nerve cells governing the vital functions do not also 

 yield as promptly to this subtile action. These are certainly 

 highly sensitive elements. Why should not the cells gov- 

 erning the cardiac and respiratory functions become 

 promptly altered, modified or dehydrated and then sus- 

 pend their activity as readily as the others? A careful 

 study of the brain and spinal cord, together with the phe- 

 nomena observed in the subject sinking to the influence of 

 an inhaled anaesthetic, answers the question to a nicety. It 

 will be admitted that the cerebral hemispheres are the most 

 highly sensitive structures in the body, and that the very 

 first real narcosis from chloroform or ether, is hypnosis 

 and then total loss of consciousness, which of course is due 

 to their influence upon these organs, i. e., the cerebral hemis- 

 pheres. The loss of consciousness in anaesthesia always 

 precedes the loss of the reflexes. If an attempt is made to 



