4G0 Observations on Inoculation loith the Virus of 



the prosecution of the investigation, even in permanently infected 

 districts. 



Sheep-pox, which stands next in order of severity, may be 

 artificially induced with certainty and comparative safety to the 

 inoculated animal. 



Foot-and-mouth disease can also be transmitted from a dis- 

 eased to a healthy animal with safety, although the artificial 

 disease is not much milder than the ordinarily benign form of 

 the natural affection. 



Pleuro-pneumonia stands alone among contagious diseases 

 of stock as an affection which cannot be transmitted from the 

 diseased to the healthy animal by the introduction of the exudate 

 from those parts of the body in which the characteristic pro- 

 ducts of the affection are deposited. I do not intend to insult 

 the common sense of owners of stock by the statement that 

 inoculation produces pleuro-pneumonia in the inoculated part, 

 but content myself with quoting the following sentence from 

 my Report of last year to the Veterinary Department : " Inocu- 

 lation with the matter of pleuro-pneumonia induces a disease in 

 the part resembling in its results the disease in the lungs." 



In no other contagious disease of the lower animals are the 

 effects of inoculation limited to the part where the virus is intro- 

 duced ; the poison of cattle-plague, even when used in minute 

 quantity, is multiplied, and rapidly passes from the point of 

 puncture over the whole system and produces all the morbid 

 changes which are characteristic of the disease. A slight scratch 

 with a needle which has been dipped in the virus of sheep-pox 

 is followed by the development of pimples (papulae), which pass 

 through the various stages exactly as they do in the natural dis- 

 ease. A little of the saliva from an animal affected with foot-and- 

 mouth complaint, if applied to the membrane of the mouth of a 

 healthy cow, causes the development of vesicles and the general 

 febrile symptoms which are distinctive of the affection. Inocu- 

 lation with the virus of glanders produces the identical disease 

 perfect in all its characters. 



Accurately stated, the question of the effects of inoculation 

 assumes this form : all contagious diseases of stock, with one 

 exception, can be artificially induced by introducing a minute 

 quantity of the virus of the disease into the system of a healthy 

 animal. This fact is so perfectly well known, that the operation 

 is commonly accepted as a test of the character of the disease. 

 If any doubt or dispute arise as to the existence of cattle-plague, 

 sheep-pox, foot-and-mouth disease, or glanders, the doubt can 

 be resolved and the dispute adjusted by the simple expedient of 

 inoculating a healthy animal with the products of the disease. 

 The results are palpable in each case. It is not necessary to 



