Septiccemia Htsmorrhagica of the Sheep. 85 



Causes. The essential cause is manifestly the bacillus, which 

 I/ignieres has isolated, cultivated in vitro, and successfuly inocu- 

 lated intravenously in the sheep, which he also infected by feeding 

 the pure cultures. Intravenously it proved fatal to Guinea pig, 

 tabbit, pigeon, chicken, rat, mouse, horse, ass and ox. Yet 

 many other accessory causes must be admitted as operating in 

 different cases. 



Youth shows the greatest susceptibility whether the victim be 

 mammal or bird. So marked is this influence that the principle 

 sufferers are lambs just weaned, or yearlings. Yet mature ani- 

 mals, that are debilitated from any cause, also fall victims. The 

 measure of immunity usually noticed in mature sheep may well 

 be attributed to a previous mild and non-fatal attack of the 

 bacillus. 



Verminous affections are undoubtedly predisposing causes, 

 Tience the common practice of attributing the malady to the 

 worms alone. This again in part explains the susceptibility of 

 the young which so often harbor worms to a dangerous extent. 

 It seems to matter less what worms are present than, that they 

 are in sufficient numbers to greatly deteriorate the health. It is 

 noticeable, however, that those worms that make breaches in the 

 mucosae, have been noted as infesting the victims of this malady. 

 In the stomach worms sent from Argentina, Railliet identified 

 Strongylus Contortus, S. circumcentus, and S. instabilis, and in 

 the duodenum S. filicollis and S. Curticei. These, like the dis- 

 tomata often found in the liver, are blood suckers and not only 

 render the animal anaemic, but make numerous perforations to 

 act as infection-atria. The various lung worms, encysting them- 

 selves in the air sacs and determining local congestions may act 

 in the same way, opening channels for the entrance of the microbe. 



Low condition or a low tone of health from any cause predis- 

 poses. Old, worn out animals, ewes in lamb, or those just lambed, 

 sheep that have been shut up and denied proper exercise in winter, 

 those on poor feeding and perhaps nursing twins, those that have 

 suffered from any debilitating disease of any kind are especially 

 obnoxious to a dangerous attack. 



Microbiology. The microbe, which I^ignieres found in the 

 pulmonary lesions, is one of the colon group of pathogenic bac- 

 teria that have been classed together as pasteurella. It usually 

 a,ppears as a very minute ovoid bacillus which stains promptly 



