402 Contagious Pleuro-pneumonia , 



the exudate in the following wav: The exudate from the lung is diluted with 

 Martin's bouillon 60-80 times and filtered through a Chamberland 's F-candle or 

 through a Berkefeld filter. The filtrate is collected in a sterilized flask, on the 

 bottom of which cattle blood serum has been placed in an amount corresponding 

 to 6-8% of exudate. Then the flask containing the filtrate is placed in a thermostat, 

 and should the fluid bei-ome opalescent in 3 to 4 days without the microscopical 

 examination demonstrating therein distinguishable bacteria, the diagnosis of pleuro- 

 pneumonia may be considered as established. 



Immunization. Immunization against pleuro-pneumonia 

 lias been employed to a considerable extent since the stand taken 

 by AVillems in 'l850, as a procedure by which healthy aniinals 

 niay be protected against natural infection. Since that time 

 it has been employe'd widely, especially in Holland, Belgium, 

 Great Britain, France, and Germany, in recent times also in 

 Africa and Australia, Avliile in England, Austria and Hungary 

 it has not met with favor. 



I. Immunization with Fluid from the Lungs. This method 

 of immunization, the principle of which consists in the injection 

 of the living virns into the stretched subcutaneous connective 

 tissue of the point of the tail, which has a low temperature, 

 affords, as proved convincingly by Willems and later also by 

 other ol3servers, the animals an immunity lasting over one year. 

 This can easily be proved by injections of virulent Mnph into 

 the loose connective tissue of the dewlap or rump,^ While it 

 produces an extensive inflammatory edema in non-immunized 

 cattle which sometimes results in the death of the animal, in 

 cattle which have been immunized a swelling not exceeding the 

 size of a nut results at the point of inoculation, and an injection 

 of virnlent hanph directly into the tissue of the lung does not in 

 any way affect their health. Practical experience coincides with 

 these results, it having been observed that immunized animals 

 become much more rarely affected through natural infection 

 than cattle which have not been immunized. 



In Willems' experiments 108 immunized cattle remained healthy after being 

 exposed to the natural infection, while out of 50 animals which were not immunized, 

 17 became affected under the same conditions. Thiernesse & Degive injected 96 

 immunized cattle with virulent lymph into the loose connective tissue of the rump, 

 whereupon they became affected only mildly or not at all, while of 33 animals 

 which were not immunized and subjected to the same infection, all contracted the 

 disease. Schiitz & Steffen inoculated 31 animals partly with warm, partly with 

 cooled IjTuph from the lungs; 12 were later placed among infected animals, but 

 remained healthy, while of four control animals three died. The remaining 19 head 

 received later virulent Ijonph injected either into the connective tissue of the 

 dewlap or into the lungs, whereupon they contracted the disease only in a mild 

 form or not at all, while all of the six control animals became severely affected 

 and three of them died. 



Under certain conditions the immunization may prove an 

 effective method of controlling the disease, especially when it 

 is very widely spread in a country, and the general obligatory 

 slaughter of the suspected animals cannot be carried out for 

 some reason, and where the danger of subsequent exposure 

 must continue to threaten the animals (in case of infection 

 involving large herds, public herds, valuable large dairy herds, 

 industrial fattening establishments). 



