44 WOUND TREATMENT 



tissues during an operation, such as rough manipulation 

 or bruising or tearing of tlie structures. By these means 

 the vitality of the tissues is lowered and their resistance 

 so impaired that the development of micro-organisms 

 which may have gained entrance is thereby favored. The 

 number and virulence of the infecting organisms, the 

 state of health of the animal, and the environment are 

 also important in connection with this subject. 



Wound Healing 



Time will not permit me to enter into the question of 

 the repair of wounds. As you are well aware, the modes 

 of healing are as follows: 



1. Primary Union or "Union by First Inten- 

 tion." — This takes place in simple incised wounds under 

 favorable conditions — that is, when there is a practical 

 freedom from infection, when hemorrhage has been 

 arrested, and the surfaces are brought into apposition 

 and kept at rest. It is the mode of healing we will strive 

 to bring about but so seldom succeed in attaining when 

 the horse is concerned. 



2. Union by Granulation and Cicatrization. — This 

 is by far the more common method of healing in horses. 

 Formerly there was an idea that the suppuration accom- 

 panying the process originated from the superficial layer 

 of cells on the recent granulations, which were arrested 

 in their development and converted into pus cells, being 

 cast off in the discharge. We know now that the cause 

 of the suppuration is the presence of micro-organisms, 

 and that union by granulation can occur without sup- 

 puration, although admitting that such is not common 

 in the horse. 



3. Union Under a Scab.— In this, repair takes place 

 beneath a scab formed by the drying of the discharges. 

 This is cast off spontaneously as soon as cicatrization 



