240 Veterinary Medicine. 



from reddish brown to black, the darkest shades corresponding to 

 circumscribed areas of actual haemorrhage. In the worst cases 

 the whole mass may appear like black currant jelly. The lungs 

 do not collapse when the chest is opened, they are more or less 

 friable at various points, and different portions will sink or float 

 in (not on) water, according as it may be more or less airless. A 

 dark liquid blood exudes freely from the torn or cut surface. 

 Sections of the lung tissue hardened and examined under the mi- 

 croscope show the alveoli and bronchioles devoid of exudate, but 

 having their cavities compressed and obliterated by the pressure 

 of the swollen mucosa, and its investing blood clot. The heart 

 is over-distended with fluid blood. In asphyxiated cases the gen- 

 eral venous system is filled with black, liquid blood, and the se- 

 rosae spotted with petechise. 



Nature. The nature of this disease is variously understood. 

 It differs from inflammation in the absence of active cell prolifera- 

 tion, and migrations of inflammatory exudation, and of fever at 

 all proportionate to the extent of the lesions. All these may and 

 do supervene if the patient survives but they are practically ab- 

 sent for a length of time at the outset. Some attribute it to pare- 

 sis of the vaso-motor centres for the lungs, as the result of their 

 over-stimulation and of the retrocession of blood from the chilled 

 surface to the internal organs. But congestions caused by cut- 

 ting the cervical branch of the sympathetic nerve or the sciatic 

 plexus are not marked by a similar blood extravasation and de- 

 struction of tissue. The delicate structure of the lung tissue and 

 the comparative absence of mechanical support will account for 

 this in part, the great force of the circulation overloading the cap- 

 illaries, under the impulse of the heart so closely adjacent, has 

 doubtless a certain effect, and the venous nature of the blood thus 

 forced into the lungs and calculated to arrest all normal function 

 has a potent influence. If we add to this, for the over-exertion 

 cases, the sudden advent into the circulatory stream of unchanged 

 peptones and other ingredients of the portal blood of highly fed 

 and plethoric animals we find a sufficiently pathogenic combina- 

 tion. In all acute cases, however, the adiposity, poor condition 

 and susceptibility to speedy exhaustion must be given their full 

 share of responsibility. 



Treatment. Girths, saddles and anything else that may hamper 



