DISEASES OF THE ARTERIES AND VEINS 477 



becomes poisoned. The septic particles are distributed over the body, and, 

 settling down in some of the more important organs, produce destructive 

 abscesses or a condition known as " pyaemia ". 



Treatment. — Any appearance of thickening in the course of the 

 jugular vein, such as we have described, should be met by prompt 

 measures of treatment. A dose of physic will first be called for, and 

 at the same time all hard corn is to be knocked off and replaced by sloppy 

 mashes of bran and scalded chaff. The wound should be repeatedly irri- 

 gated by carbolic solution and covered with antiseptic gauze. Hot 

 fomentations applied over the injured vein will aid in reducing inflam- 

 matory action and checking the progress of the disease when permissible. 

 Should abscesses form, they will require to be oiDened, and to be well 

 syringed out with antiseptic dressing from time to time and packed 

 with antiseptic wool. 



Some practitioners recommend a blister to the swollen vein, and place 

 complete reliance on this form of treatment. There can be no doubt 

 that in some subacute and slowly progressive cases such a course might 

 prove beneficial, but in the more active and severe attacks the course 

 recommended above would be more appropriate. 



ANEURISM 



Under certain conditions arteries are liable to undergo dilatation in 

 certain 'parts, so that the cavity of the vessel is more or less enlarged. 

 Such a state is known as an aneurism. This form of disease is more 

 especially seen in foals and young horses, as a result of the presence of 

 parasites in the large vessels which supply blood to the bowels. It may 

 also be brought about by sprain or any injury which may induce inflam- 

 mation and consequent softening of the vessel. Aneurism is sometimes 

 seen in the aorta, as it courses beneath the spine, and more rarely in some 

 other of the smaller vessels. In some instances the presence of the 

 tumour does not seem to give rise to any disturbance in the circulation 

 which can be recognized during life, and is therefore only discovered after 

 death. Where, however, the dilatation is considerable, it may very seri- 

 ously incommode the circulation, and by causing obstruction lead on to 

 hypertrophy, with dilatation of the walls of the heart and embarrassment 

 in the breathing. 



In the horse, aneurism most frequently occurs in the anterior mesenteric 

 artery as the result of injury done to the walls of the vessel by parasites 

 (Strongylus armatus). How these creatures gain access to the vessel is not 

 exactly decided, but most likely by boring their way through the tissues 



