WOUNDS 407 



In addition to the poison they form in the wound, some micro- 

 organisms are themselves capable of entering the blood and tissues of 

 the body. Here they grow and multiply, and add to the store of poison 

 entering from without, and by their presence produce that condition of 

 the body known as septiccBrtiia. 



When the invading organisms enter the blood in large numbers, they 

 may provoke it to coagulate around them, and the small clots so formed, 

 by jalugging the capillary vessels, form scattered centres of inflammatory 

 action and pus formation in different organs and parts of the body, con- 

 stituting another variety of blood-poisoning — pycemia. 



The more seriously the tissues are damaged at the time when the 

 wound is inflicted, the more vio;orous is the o-rowth and action of the 

 invading organisms. The diminished vitality of the one having reduced 

 their powers of resistance, renders them more amenable to the action of the 

 other. It is for this reason that torn and contused wounds heal so much 

 more slowly than others inflicted with a sharp instrument. 



Although, as we have seen, the evil consequences resulting from bacteria 

 and their products may be serious, and even fatal, their occurrence in the 

 horse is, comparatively speaking, rare. Every day horses with deep, 

 gaping wounds may be seen, having no protection of any kind, and little or 

 no medical care, yet they pass through their trouble with little or no more 

 discomfort or suff"ering than is occasioned by the jjrolonged period of 

 healing resulting from the local inflammation which the micro-organisms 

 and their products excite. 



Still, notwithstanding the natural resistance which wounded flesh offers 

 to the entrance of bacteria and their products into the system, it happens 

 from time to time that the one proves too feeble to exclude the other, 

 hence it has been found necessary in the treatment of wounds to resort to 

 special methods by which to destroy and exclude from them all offending 

 organisms. This mode of treatment, first devised and practised by Lord 

 Lister, is known as the antiseptic system. It is based on the fact that 

 such bacteria as prove inimical to wounds, and endanger life by poisoning 

 the blood, are capable of being destroyed or inhibited in their action by 

 the application of various dressings composed of certain chemical substances 

 in the form of powder or solution. The more common agents employed 

 for this purpose are carbolic acid, perchloride of mercury (corrosive subli- 

 mate), iodoform, boric acid, &c. See pp. 420, 421. 



Healing under a Scab. — This is nature's method of repairing 

 wounded parts, and in suitable circumstances the best that can be de- 

 vised. It is well illustrated when, after the surface of the skin has been 

 broken, the blood and other exuded matters are allowed to dry upon it. 



