644 ADMINISTRATION OF MEDICINES. 



means of warm water, or for destroying worms by, for instance, oil 

 of turpentine mixed with linseed oil. For this purpose, a Read's 

 enema pump (Fig. 160, p. 645) is frequently used. The value of 

 an injection of this kind in constipation is enhanced by the fluid 

 being sent a good distance into the bowel. 



There is no doubt that an enema given in the ordinary way is 

 almost useless; because the injected fluid does not penetrate more 

 than four or five feet into the bowel. Colonel Fred Smith has 

 devised a good form of enema tube, which is 6 ft. long, and may 

 be used with Read's enema pump. There is no diSiculty in passing 

 it ; having been oiled, with gentle pressure, it finds its way along 

 the course of the rectum, and when it refuses to go further no 

 force should be used ; all that is required, should it be necessary 

 to pass it further forward, is to pump in a gallon or two of water, 

 which dilates the bowel in front of it, and the passage is accom- 

 plished. A simpler and probably a better plan is that of having 

 the hind quarters raised while the enema is being given (p. 420). 



Water for enemas should be but little warmer than the tempera- 

 ture of the body, say, not more than 103° F. It should not be 

 mixed with soap or any other addition. 



An assistant holds up the near fore foot. The operator having 

 filled the clyster pipe and oiled its nozzle, inserts it very gently 

 into the anus. The fluid is then injected. 



The rectum has great power of absorbing water, as we may 

 learn from the fact, that it is the place in which the dung assumes 

 its normally dry condition. Hence, it is a valuable route for the 

 introduction into the system of medicines which are dissolved in 

 water. To facilitate absorption by this means, the dung in the 

 rectum should be cleared out by back-raking (p. 649), and the 

 solution should be of small bulk. Unlike the mucous membrane 

 of the mouth, the mucous membrane of the rectum does not 

 excrete sufficient fluid to dissolve ordinary dry medicines, which 

 consequently should not be given in this way. Also, its power 

 of absorbing oils is feeble. -When injecting a small quantity of 

 fluid, say, about 1 oz. into the rectum, it is well to use a narrow 

 tube with the syringe, or a catheter (p. 666) might be employed. 

 This method of injection is not suitable to cases in which the 

 mucous membrane of the intestine is in a state of irritation. 



By Subcutaneous (Hypodermic) Injection. 



In this way, exactness in the amount of the dose can be insured 

 better than by the mouth or rectum. With " difficult " horses, it 

 is often easier to make a subcutaneous injection, than to give a 

 ball or drench. This method is frequently indispensable for 



