DISEASES OF THE BONES. 769 



fine pointed irons for pyro-puncturing should be used only when 

 at a white heat, and never when cooled to a red heat. The reason 

 for this is that there is much less pain felt when the iron is at a 

 white heat, as the sensibility is almost immediately destroyed. It 

 is desirable to have three or four irons heating at once, so as to 

 be sure of having one continually at white heat. 



The method of using it is to barely touch the skin at first to 

 mark the points to be punctured, which should be extended out 

 some little distance beyond the line of enlargement or immediate 

 seat of trouble (as shown in Fig. 666). Then repeat, burning 

 much deeper each time until the holes are made to a depth of 

 about three-eighths of an inch, more or less, according to the 

 severity of the case. Where there is much enlargement, penetrate 

 to the bone proper over that part. When the firing is complete, 

 rub on thoroughly a strong blister. The f ollowing simple Spanish 

 fly blister is good : 



1 ounce Spanish flies. 

 ^ ounce liquid tar. 



2 ounces lard. 



Mix, and rub on thoroughly from five to ten minutes, putting on a pretty 

 thick application, and leaving on about forty-eight hours, when wash off with 

 warm water and soap. When dry, rub on some grease or lard; and let the 

 animal rest three weeks. 



The principle is to keep the horse quiet long enough to give 

 time for exudate to be thrown out and unite the parts in- 

 volved, and this requires from three to five or eight weeks, and in 

 some obstinate cases possibly even longer, depending upon age; 

 the younger, the more easily and quickly this will be done, while 

 the older the horse, and the less constitution, the slower and more 

 difficult it will be to do. In any event, it must be continued 

 or repeated, until the lameness disappears, after which work mod- 

 erately for a while. 



If, after a couple of months or so, there is any perceptible 

 lameness or soreness, an ordinary biniodide of mercury blister may 

 be applied once or twice, as the case requires, or the firing may 

 be repeated, as before stated. The point is to keep up sufficient 

 counter irritation to make the cure complete. It will also aid in 

 removing any enlargement that may remain. 



49 



