Immunization. 4()5 



losses were observed (Xoeanl) . During 1902, out of 1,955 immunized animals nine died, 

 while 257 lost their tails (the inoculations were made in this instance during unfavor- 

 able weather). In 1903 and 1904 attenuated cultures were used for the immunization, 

 and on this occasion out of 5,554 animals only one clied, and only 88 cattle lost 

 their tails. 



According to Yohowskj-'s report immunization with pure cultures also gave 

 tatisfactory results in Eussia, only he emphasizes the fact that cattle which had not 

 reacted to the inoculation should be inoculated the second time after 20 to 25 days. 

 Very favorable results are likewise reported from Eussia and Siljeria by Dorofeew, 

 Mukarewsky and Stahl. 



Cattle may also be immunized effectively by intraocular injections of pure 

 cultures (Xocard & Eoux). 



III. Serum Inoculation. Altliou^li the serum of healthy 

 cattle and those which have recovered from the disease, pos- 

 sesses no immunizing properties, animals which become affected 

 as a result of subcutaneous injections of a small quantity of 

 pure culture and have again recovered, and which have sub- 

 sequently received during several months subcutaneous injec- 

 tions of up to over 6 liters of culture, produce a potent serum, 

 although it has no agglutinating or bactericidal properties. 

 A subcutaneous injection of 40 cc. of such serum produces an 

 immunity lasting from 8 to 10 days, while 40-60 cc. checks the 

 further development of an inoculation-swelling produced by 

 a virulent injection. After the appearance of the fever re- 

 peated injections of 100-200 cc. of serum are required to exert 

 a curative action; at still later stages it is not possible, even 

 by very large injections, to check the process in the lungs 

 (Nocard). 



Veterinary Police. As the treatment of affected animals 

 does not promise results, the complete eradication of the disease 

 by veterinary police measures is of special importance. As 

 the virus remains virulent in the body of affected animals for 

 a long time, even in cases showing improvement, it can onl}^ 

 be destroyed by the slaughter of all cattle which are supposed 

 to harbor it in their bodies. In this regard, besides the affected 

 and exposed animals even those should be considered which 

 are suspected of having been affected, as suspicious s^miptoms 

 of the disease appear only relatively long after the infection 

 in a perceptible manner. 



This attitude has been assumed by the legislative bodies 

 of those countries which earnestly desired the complete eradica- 

 tion of contagious pleuro-pneumonia, and by an energetic prac- 

 tical execution of this principle, and by satisfactory compensa- 

 tion of the owners, the desired end has been achieved. However 

 the killing of all the suspected animals in localities where the 

 disease is widely spread, especially in large dairy herds, fatten- 

 ing establishments, and pul)lic cattle herds, is hardly possible 

 of execution without great danger to the stock industry. There- 

 fore in such herds the isolation or quarantining of the suspected 

 animals for a period of at least six months should be considered, 

 and further, in order to reduce the individual susceptibility the 

 application of occasional immunization, particularly since by 



