Acute Lymphangitis of Plethora in the Horse. 387 



or three times its natural thickness, and the swelling has extended 

 well up on the thigh. The swelling has a soft cedematous feeling, 

 easilj' receiving and retaining the imprint of the finger and is not 

 only hot, but excessively tender. From the margin of the swell- 

 ing, firm, tender, rounded cords are found to emerge passing up- 

 ward along the line of the saphena vein and its branches toward the 

 inguinal glands. These represent the swollen and gorged 

 lymphatic trunks, and may often be traced for some distance into 

 the substance of the general engorgement. 



When the inflammation is violent, suppuration may ensue at one 

 or several centers, but more commonly the engorgement goes on 

 increasing and when the febrile attack has subsided the limb is 

 left permanently enlarged and correspondingly liable to a second 

 attack. 



Milder cases are met with which are perhaps even more mis- 

 leading. There may be little or no rise of temperature, loss of 

 appetite or general constitutional disturbance, but under some 

 change of regimen and particularly after one or two days of rest 

 the subject becomes lame in one hind limb, without any of the 

 usual injuries to account for it. Examination of the groin shows 

 swelling and tenderness of the external inguinal glands, with or 

 without, a tender cord-like swelling running down from them. 



Between these two types may be found all grades of lymphatic- 

 inflammation with a varied degree of attendant constitutional dis- 

 turbance. 



Lesions. The coats of the inflamed lymphatic vessels are 

 thickened by exudate and the Outer coat is the seat of ramified 

 redness with minute spots of blood extravasation. The inner 

 coat is dull, opaque, or even thickened. The vessel is dilated 

 and its walls friable. The contained lymph in the intervals be- 

 ttween the valves has coagulated into a very thin diffluent jelly- 

 like clot, which in old standing cases may have become granular. 

 The connective tissue from which these vessels lead is infiltrated 

 with liquid and the lacunar spaces distended. Red patches from 

 blood extravasations are numerous. The external inguinal 

 glands and often the internal and sublumbar are swollen, con- 

 gested, and the seat of active cell hyperplasia. Abscesses are ex- 

 ceptionally seen. 



In chronic cases the lymphatic vessels of the affected limb and 



