440 THE HORSE. 



aS possible. The various formulas for blisters will be given in the 

 list of materia medica. 



CASTEATION. 



For removing the testicles several methods of operation 

 have been proposed ; but hitherto none has been tried which is so 

 Buccessful as the old plan, in which the division of the cord is per- 

 formed by a heated iron with a sharp edge. In human surgery 

 the spermatic artery is tied, and all danger of hemorrhage is over, 

 because the small amount of bleeding which takes place from the 

 artery of the cord is of no consequence, as it cannot enter the cavity 

 of the peritoneum. In the horse, on the other hand, the inguinal 

 canal communicates with that cavity, and if the ligature is used, 

 there is a double danger of inflammation — first, from efi"ased blood, 

 and secondly, from the irritation of the ends of the ligature. This 

 plan, therefore, is now generally abandoned, though some few prac- 

 titioners still adhere to it, and the choice rests between two methods 

 of removal by cautery, namely, the actual and potential, — the 

 former giving more pain at the moment when the heated iron is 

 applied, but the latter being really far more severe, as the caustic 

 is a long time in effecting a complete death of the nerve and other 

 sensitive parts. Torsion of the vessels has been also tried, but it 

 is often followed by haemorrhage, and, moreover, the pain which 

 is caused during the twisting of the artery is apparently quite as 

 great as is given by the heated iron. We are all inclined to fancy 

 that fire occasions more agony than it really does, but those who 

 have in their own persons been unfortunately able to compare the 

 effects of the two kinds of cautery, have uniformly admitted that 

 the actual is less severe than the potential, if the two are used so 

 as to produce the same amount of cauterization. 



The best period for performing the operation on the 

 foal is just before weaning, provided the weather is mild. If, how- 

 ever, his neck is very light, and the withers low, its postponement 

 till the following spring will give a better chance for the develop- 

 ment of these parts. The cold of winter and heat of summer are 

 both prejudicial, and the months of April, May, September, or 

 October should always be selected. 



No preparation is required in the "sucker," but after wean- 

 ing the system always requires cooling by a dose of physic and 

 light food before castration can safely be performed. Horses which 

 have been in training, or other kind of work attended with high 

 feeding, require at least three weeks' or a month's rest and lower- 

 ing, by removing corn, mashing, &c., together with a couple of 

 doses of physic, before they arc fit to be castrated. 



For the ordinary method op operating, a pair of clams 

 should be provided, lined at the surfaces where the compression 



