682 OPEEATIONS. 



sun for a few hours may cause a rise of as much as 3.5° F., and 

 the effects of cold and rain may equally lower it. I have often 

 seen horses in India and South Africa have a temperature of 105° 

 F., without any derangement to their health, when they were 

 picketed in the open during hot weather. 



The average internal temperature of a healthy horse is about 

 100° F., varying, say, from 99° to 101° F. Cadeac puts it at 

 from 99.5° to 100.4° F. Professor Hobday finds that the average 

 temperature is 100.3° W. As an approximation, we may say 

 that a rise or fall of more than 2° F. is not compatible with 

 health, unless there have been specially exciting causes. Re- 

 ferring to India, Haslam states that among healthy horses at rest, 

 the range of temperature is from 98.5° to 100.5° F. ; and among 

 apparently healthy, though poorly-fed '^grass-cutters'" ponies, 

 from 97.4° to 101.4° F. 



Tourniquet and Esmarch Bandage. 



A tourniquet is an instrument which is used to stop the circula- 

 tion of blood in a part, by pressure on the local blood-vessels. 

 Usually, it consists of an india-rubber tube, which is about f 

 inch in diameter, and is very rarely applied to any part, except 

 the limbs. Its chief value is in the prevention of bleeding during 

 surgical operations, such as those of neurotomy (p. 668) and re- 

 moval of splints (p. 242), in which cases, the tourniquet is best 

 applied two or three times round the leg above the knee ; because, 

 if it is put on below the knee, its pressure will be unequally dis- 

 tributed, owing to the almost total absence of muscles in that 

 part. The most generally useful form of tourniquet is Arnold's 

 Reliance Tourniquet, which is an india-rubber tube about 2J feet 

 long, and provided with a flat hook, through which the other end, 

 after compression by the finger and thumb, can be passed (Fig. 

 174). If this flat ring is of the proper size, the end of the tube 

 cannot be pulled through it, and it can be released only by 

 taking it out of the ring. We can improvise a good tourniquet, 

 by wrapping round the leg an ordinary rubber tube, which can 

 be obtained from any ironmonger, and securing it by a reef knot 

 (Fig. 175). This tube will have to be about 4 feet long, because 

 it is not so elastic as specially made tubes. Tourniquets are 

 sometimes provided with a pad to be placed over the principal 

 artery or arteries of the part, so as to increase the effect of the 

 pressure; but this arrangement is seldom necessary in horse 

 practice. 



As a tight tourniquet more or less stops the passage of blood 

 underneath it, there will be comparatively little bleeding from a 



