DISEASES OF THE POLL. 783 



The establishment of the svippurative process, even before 

 any local symptoms have been manifested, is betrayed by the 

 changed appearance of the animal. As described in the previous 

 pages, he becomes listless and dull, standing quietly with the 

 neck extended and the head resting on the manger; refusing to 

 move, or if doing so, never raising his head, and by grunts and 

 moans betraying the great pain he is suffering. If his head be 

 raised by force he rebels against it, struggles, goes backward, 

 strikes with his fore feet, and perhaps rears. 



By bringing the animal under control and restraint, as by 

 throwing him, the abscess may be easily discovered, on one side 

 of the neck, as a diffused swelling, tense, warm, and so excessively 

 sensitive to the sHghtest contact, that it is with the greatest diffi- 

 culty that an obscure and deej) fluctuation can be detected. The 

 positive nature of this tumor must then be made out as early as 

 possible, by repeated capillary explorations, since if discovered to 

 be unmistakably of a suppurative nature, a free exit to the pus 

 must be at once established, to avoid its necrotic tendency ; while 

 if it be a cyst, there is danger in opening it, arising from its lia- 

 bility to be followed by necrosis of the cer\ical ligament. 



The prognosis of this abscess will vary according to the 

 length of time which may have elapsed between its incej^tion and 

 its detection. The serious nature of this prognosis is explained 

 by the fact of tho incomjjressibility of the pus and the inextensi- 

 biUty of the aponeurosis of the splenius and complexus muscles, 

 which resist the swelling of the inflamed tissues, and by their 

 compression and strangulation, become the cause of gangrene. If 

 a diagnosis of abscess is made, and it is immediately opened, the 

 cavity may assume the character of an ordinary abscess, and close 

 entirely ; but this is a rare termination. More ordinarily, the incar- 

 ceration of the infiltrated pus between the muscular layers is an 

 obstacle to its free and complete discharge, and it remains infil- 

 trated, gathering into cul-de-sacs, and migrating irregularly be- 

 tween the muscles. Hence the formation of so many fistulous 

 tracts, opening at diverse points on the skin, which are generally 

 the result of the necrosis of the ligamentum nuchse, or of the 

 fibrous tissue of the tendons, or even of that of the atlas, or 

 possibly of the occipital bone. 



All the dangers which are likely to follow the existence of an 

 abscess at the poll, demonstrate the necessity for prompt surgi- 



