INTRAPERITONEAL INJECTIONS 713 



solution, barium chloride, silver colloid chloral hydrate, 

 and a few other remedies may be injected into the jugular 

 vein of the horse and ox ; in the saphena vein of the dog. 

 The injection should be diluted, non-irritant, and introduced 

 slowly with strict attention to asepsis. The introduction 

 of air, the formation of clots, and septic contamination must 

 be avoided. 



Intraperitoneal injections are serviceable for the adminis- 

 tration of physiological salt-solution and other artificial 

 sera, and chloral as a general anaesthetic. The injection is 

 made at the upper region of the left flank, which is punctured 

 with a fine trocar and canula ; the trocar having been 

 withdrawn, the nozzle of the syringe is inserted in the 

 canula. The usual aseptic precautions should be observed. 



On the skin many medicinal agents are applied, most 

 of them such as counter-irritants, caustics, and poultices 

 for the production of local effects, or of reflex actions exerted 

 on adjacent or distant parts. The skin, protected by 

 epidermis, although it absorbs oxygen and other gases, 

 excretes carbonic acid, and takes up water from baths or 

 from wet clothing, especially if there is a deficiency of fluid 

 in the body, does not absorb drugs unless they are dissolved 

 in chloroform or other agent which promotes penetration. 

 Drugs, whether in alcoholic or watery solution, are absorbed 

 through the unbroken skin only in very small amount and 

 tardily ; but when the epidermis is removed by a blister, 

 the true skin readily absorbs drugs placed on it. By this 

 endermic method, morphine was formerly used for the pro- 

 duction of its general anodyne effects, but the hypodermic 

 method is more convenient, and is now generally preferred. 



The hypodermic administration of drugs, and mallein, 

 tuberculin, the various sera and vaccines, consists in their 

 injection in solution into the subcutaneous cellular tissue. 

 They thus enter the blood-stream unaltered by contact with 

 the contents or secretions of the digestive canal. They 

 escape the changes which many substances undergo in the 

 liver, and hence act more certainly and rapidly. Hypo- 

 dermic injection is specially indicated 



(1) Where rapid energetic effects are required, as 

 in poisoning, internal haemorrhage, threatening 



