l6 QUATERCENTENARY STUDIES IN PATHOLOGY 



undoubted reaction, while, in culture, the same organism is completely 

 decolorized. This I do not regard as a true reaction in any respect. 

 If the organism be one which gives a true reaction, this should be forth- 

 coming, both when it is growing in the native liquid, and when it has 

 been cultivated on an artificial medium. 



Inoculability. — When a small quantity, say half a cubic centimetre or 

 less, of the peritoneal liquid containing spores is injected subcutaneously, 

 and more surely if a few cubic centimetres of dilute acetic acid be injected 

 side by side with it, the animal dies usually in from twenty to thirty-six 

 hours afterwards. Some sheep are more resistant than others, but the 

 experiment seldom fails to bring about a fatal issue, provided the animal 

 be a one-year-old, and the experiment made during the months of 

 prevalence of the disease. 



I inject the liquid on the inner aspect of the thigh, as here the skin 

 is free from wool and is cleaner than elsewhere. In a few hours after 

 performing the operation the animal exhibits signs of distress. It has a 

 dull expression, remains apart from its mates, ceases to feed or 

 ruminate, and the inoculated limb is lame and has begun to swell. 

 By a matter of from sixteen to twenty hours, these phenomena have 

 become aggravated, the sheep has probably fallen over in a helpless 

 state, may be delirious, and finally passes into a comatose condition for 

 an hour or so before death. 



At the autopsy the injected limb, sometimes indeed both limbs, and 

 the front of the abdomen, are found intensely oedematous, so much so 

 that occasionally the skin has ruptured and the liquid is escaping. The 

 muscles for some distance round the point of inoculation are infiltrated 

 with blood, and the areolar tissue is blown up with gas. The peritoneal 

 liquid, as a rule, is abundant, opaque, and blood-stained, and, on micro- 

 scopic examination, is seen to be literally swarming with the characteristic 

 rod, which is sporing on all hands. The oedematous liquid of the 

 inoculated limb also contains it, but not so abundantly as the liquid 

 of the peritoneal cavity. It is usually absent from the heart's blood. 



The organism is thus one of extreme virulence for the sheep, causing 

 the death of the animal in a few hours after its introduction subcu- 

 taneously. It can also be inoculated upon the guinea-pig or rabbit, 

 although apparently they are naturally immune to the disease. 



Portal of Entrance. — The question of how, in the natural disease, 



(.6) 



