HOESE SICKNESS. 483 



poisonous effect on the system, " Horse sickness appears to be a septicsemia 

 in the further sense that death is due to the toxic effects of substances manu- 

 factured by the bacteria multiplying in the blood. No doubt in those cases 

 in which there is very extensive pulmonary oedema, interference with the 

 airalion of th« blood will act as a contribiiiary cause of death, or it may be 

 the final cause ; but in a considerable number of the experiments recorded in 

 this article, the combined structural lesions, such as the oedema of the lungs 

 and the exudation into the pleural and pericardial sacs, were not sufficient 

 to account for the fatal issue. It ought also' be noticed that the microbe of 

 horse-sickness does not appear to attach itself to the red corpuscles of the 

 blood ; at least, that seems to be indicated by the fact that these corpuscles 

 appear quite normal in preparations made from the blood, and by the normal 

 tint of the serum furnished by horse-sickness blood" {McFadyean). This 

 eminent bacteriologist considers that it is highly probable that the agent of 

 infection of horse sickness is too small to be made visible to the human eye, 

 even when aided by the highest powers of the best modern microscopes. 

 He supports this opinion by the fact that " horse-sickness blood is not 

 deprived of its infective property by filtration through a Berkefeld or a Cham- 

 berland filter," either of which might arrest some of the cont-ained bacteria 

 (" Journal of Comp, Path.", June, 1901). 



POST-MORTEM EXAMINATION.—" Throughout the course of 

 numerous past-moj'teui examinations one negative feature stands 

 out in remarkable prominence, namely, the almost total absence 

 of any true inflammatory phenomena ; while the conditions obtain- 

 ing might be, for the most part, ascribed to acute venous con- 

 gestion with exudation of blood plasma" (Edington). This fluid, 

 which is either clear or more or less stained with blood, is found 

 in large quantities in the windpipe, pericardium, lungs, pleural 

 cavities, and other parts. Edington states that in one case he 

 removed seven pints of this fluid from the pericardium, but that 

 the amount as a rule is under five pints. Although the blood is 

 darker than usual, it does not in any way possess the tarry appear- 

 ance which is characteristic of anthrax. It coagulates with 

 extreme quickness. 



" Whichever variety of the sickness the animal may have suffered 

 from, it is usual, though not an invariable rule, to find a huge 

 cloud of white foam around the mouth and nostrils of the dead 

 animal. This usually remains unchanged to any gi'eat degree for 

 a long time, even during exposure to a hot sun. . . 



" On making an incision into the subcutaneous tissue of the 

 neck, along the line of the windpipe, it is common to find lying 

 along, and in many cases surrounding the windpipe and the larger 

 vessels, a quantity of clear yellow jelly, which consists of blood 

 serum that has been pressed out of the vessels in this situation, 

 and has subsequently undergone coagulation. If the windpipe is 

 opened, it will be found to contain yellow fluid in all stages of 

 conversion into the white froth that one may notice after death 

 around the nose and mouth. 



" On opening into the large blood vessels in this area, the blood 



31* 



