168 THE HORSE IN HEALTH AND DISEASE 



Attention is called in this connection to the use of hydrogen 

 peroxid as a surgical antiseptic, for the reason that it is much less 

 valuable than is popularly believed. In the presence of organic 

 matter it rapidly reduces and loses its disinfectant property. It 

 is a powerful deodorant, but should not be relied upon as an anti- 

 septic. Compared with carbolic acid it is about -g-j^Tir ^^ efficient. 

 When applied to a wound with much pus accumulation it acts 

 mainly as a mechanical agent to bring the tissue debris from the 

 depths. 



Wound healing is the process by which the destroyed tissue is 

 replaced and the normal condition is restored. The rapidity and 

 completeness of recovery is determined by the form of wound 

 healing which takes place. The three following forms are easily 

 recognized : 



(1) Healing by primary intention consists of a direct and rapid 

 union of the margins of the wound without the formation of pus. 

 In order that a wound may heal in this manner it must be fresh and 

 non-infected, have even edges, and have lost but little substance. 

 Minor cuts and other wounds of man heal by this method if kept 

 free from organismal contamination. In our domestic animals 

 these conditions are found only in operation wounds, and then 

 only when protection is afforded by bandages. Within twenty- 

 four hours the edges of the wound adhere with blood, afterward a 

 fluid-like substance, wound cement, performs this function. The 

 surface of the wound remains dry. In four to eight days definite 

 union results, and a small scar is the only sign left of the injury. 



(2) Healing by secondary intention is characterized by the 

 production of granulation tissue, and is generally accompanied by 

 pus formation as a result of infection from pus-producing organ- 

 isms. Old wounds, infected wounds, and wounds with loss of 

 substance heal under this method. The granulation compensates 

 for the destroyed tissue, and also forms an important protection 

 against the entrance of any infectious material into the blood- 

 stream where it might be spread to all parts of the body. It is a 

 good sign to see granulations appear in a wound, for there is then 

 no further danger from absorption of poisons. This function of 

 granulation tissue has been demonstrated by placing pure cul- 

 tures of anthrax bacilli on a granulating wound of a sheep. The 

 disease did not develop, even though sheep are very susceptible to 

 anthrax. 



