INFECTIOUS PLEURO-PNEUMONIA. 243 



Nocard does not accept Arloing's conclusions, and expresses the 

 opinion that the virus is particulate, but is not due to any micro- 

 organism which can , be detected or cultivated by the methods 

 at present adopted. In the opinion of the author, who has 

 also examined the micro-organisms in pleuro-pneumonia, it is 

 fuUy justifiable to regard the nature of the contagium as 

 unknown. 



Preventive Inoculation. — In 1852 Willems introduced inocula- 

 tion. The liquid from the lungs of an animal with pleuro-pneumonia, 

 which had recently died, was inoculated in the extremity of the tail 

 by a puncture with a lancet. Swelling occurred at the seat of inocu- 

 lation, and on recovery the animals were believed to be protected. 

 A Dutch Commission reported that the inoculation gave a temporary 

 protection. A Belgian Commission in the following year reported 

 that the phenomena of inoculation could be produced several times 

 in succession in the same animal, and that it was not a certain 

 preventive. A French Commission in 1854 concluded that a power 

 of resisting infection was given, but the period was undetermined. • 

 Protective inoculation continued to be employed, and, various modi- 

 fications of the method were introduced. Threads soaked in lymph 

 were inoculated, or the lymph subcutaneously or intravenously 

 injected. 



The usual result of the inoculation is swelling and, in about ten 

 or fourteen days, effusion of straw-coloured fluid, which is occasion- 

 ally blood-stained. Gangrene may follow, involving amputation of 

 the tail. Germont and Loire in Queensland adopted the method — 

 which was suggested by Pasteur — of inoculating calves ,in the loose 

 cellular tissue behind the shoulder. This produces intense oedema 

 and a quantity of lymph. There has been much controversy with 

 regard to the value of protective inoculation. 



Stamping-out System. — Brown maintains" that pleuro- 

 pneumonia can be exterminated only by slaughter of the diseased 

 animals, and quotes the results experienced in the Netherlands in 

 support of his views. 



In 1871 slaughter for pleuro-pneumonia was commenced in the 

 Netherlands. There were 6,000 cattle attacked by the disease. In 

 1872 owners were compelled to slaughter not only diseased cattle, 

 but those which had been in contact with them, unless inoculated, 

 and the attacks were, in consequence, reduced to 4,000. In 1873 it 

 was forbidden to move cattle out of infected districts, and the attacks 

 were reduced to 2,479. In 1876 slaughter of the whole herd was 

 decreed, and during the first year of this heroic system the cases fell 



