62 THE APPLIED PHYSIOLOGY 



blood-pressure regains its normal standard. During an 

 operation such as a high amputation it will be found 

 that the fah 1 of blood-pressure is induced principally 

 by the division of the great nerves ; in abdominal 

 operations, by evisceration or by dragging on the 

 organs. 



According to Crile and Mummery, surgical shock 

 is due to exhaustion of the vasomotor centre in the 

 medulla of the brain. In consequence, the small 

 arteries are allowed to dilate, blood collects and 

 stagnates in them, especially in the capacious vessels 

 of the abdomen, and there is not enough circulating 

 blood to maintain the proper supply to the brain and 

 other important structures. Sherrington has shown 

 that there is in practice another factor, namely, a 

 concentration of the blood, owing to loss of water, 

 from the vessels to the tissues. 



It is possible only to summarize briefly the 

 practical deductions as to our best means of com- 

 bating surgical shock : the fascinating original 

 papers should be consulted by any who have not 

 read them. It is clear, in the first place, that when 

 dealing with a patient with a crushed limb, it is 

 futile to " wait for the shock to pass." It is the 

 crushed nerves which are maintaining the shock. 

 Injection of nerve trunks with cocaine or novocain 

 five minutes before dividing them prevents com- 

 pletely any fall of blood-pressure or other evidence 

 of shock during amputations. The writer has 

 successfully employed injections of 5 minims each of 

 2 per cent novocain into the anterior crural and 

 great sciatic nerves, in amputating through the 



