266 DADDS VETERINARY MEDICINE AND SURGERY. 



wash off the blistering matter, thereby saving loss of hair; but 

 there is more of apparent than real good in this plan. If a blis- 

 ter be necessary, it requires all its activity. 



Ammoniacal blister. — Spanish flies are only efficacious when the 

 animal can afford to wait their action, which is rather slow. In 

 most of the acute diseases, the horse would perish before the blis- 

 ter began to rise, wherefore resort has been had to boiling water 

 and red-hot iron. The action of these last coarse and brutal 

 measures was alone controlled by the violence of the internal in- 

 flammation, and, if the practitioner was mistaken in his estimate 

 of the immediate danger, extensive and lasting blemish was the 

 consequence. We have in the liquor ammonia an agent quite as 

 formidable as boiling water or heated iron, but it is rather longer 

 in displaying its force ; wherefore, it allows time for watching its 

 action, and of checking it the instant it has sufficiently blistered 

 the skin. It is true the liquor ammonia upon the skin can not be 

 removed, neither need it be counteracted. Ammonia is like steam, 

 only powerful when confined. The ordinary soap liniment, if 

 covered over, would, because of the ammonia it contains, produce 

 a lasting blemish ; but every veterinary surgeon knows how very 

 harmless a preparation that is when simply rubbed upon the sur- 

 face. So, when we desire the active effects of liquor ammonia, we 

 double a blanket or rug four or five times and hold it over the 

 liquid. It takes from ten to twenty minutes to raise a blister, and 

 it consequently can, from time to time, be observed; and when its 

 action has reached the wished-for point, all we have to do, effectu- 

 ally to stop it, is to take away the rug or blanket. That removed, 

 the free surface and the heat of the body occasions the ammoniac d 

 vapor to be dispersed, and the animal is safe. 



RO WELLING. 



Kowels acts as foreign substances within the body. They cause 

 irritation and suppuration, whereby more deep-seated inflamma- 

 tions are supposed to be removed. They are, however, often very 

 convenient, because they stand as sign-boards to show the proprie- 

 tor that something has been done. The common mode of making 

 a rowel is after the following manner: A slit is first made by 

 means of the rowel scissors, on any part of the integuments, held 

 between the fiucrer and thumb. With the handle of the scissors 



