No. 4.] REPORT OF CATTLE BUREAU. 191 



tcctod iimuunily from the disease.^ This principle of coni- 

 biniiig an active virus and a serum at the same time was first 

 adoi)tcd by Koch in immunizing cattle from rinderpest in 

 South Africa. 



A recent adaptation of the same principle is one for pro- 

 tecting from rabies dogs that have been bitten by rabid dogs. 

 The material is obtained from the Pasteur Institute in New 

 York and costs $20 per dog. The dog is given the first in- 

 jection under the skin in the region of the flanks, as soon as 

 possible after being bitten, and in about two weeks the second 

 injection is given, a more powerful material being used the 

 second time. If the dog remains free from rabies for two or 

 three weeks after the second injection he will not develop the 

 disease, and also has an immunity from rabies conferred upon 

 him which, it is claimed, will last for a year and a half or 

 longer. This immunity is conferred in much the same way 

 as the immunity from hog cholera ; that is, serum from a 

 hyperimmunized sheep is mixed with a certain amount of 

 fresh brain from a rabid rabbit, and used first in a mild 

 streng-th and later in a much stronger mixture. This treat- 

 ment has not yet been tried on humans ; persons bitten still 

 have to take the usual Pasteur protective treatment. It has 

 not been used upon other animals than dogs, because horses 

 and cattle would take so much that the expense would be 

 almost prohibitive. 



Iowa, it is said, has about 7,000,000 swine and Illinois 

 about 5,000,000. In such States this method of immuniza- 

 tion would be most valuable, and ought to be taken up by the 

 State live stock sanitary boards. In Massachusetts there are 

 only about 85,000 swine and only a few large herds, most of 

 them being kept by persons who own but a few animals; and 

 considering the amount of hog cholera occurring in this State 

 it is a question whether or not it would be worth while for the 

 Commonwealth to establish a small farm and laboratory for 



' Anyone interested in a full and detailed account of the work done at the experiment 

 farm of the United States Department of Agriculture at Ames, la., is referred to Bulle- 

 tin 102 of the Bureau of Animal Industry. United States Department of Agriculture, 

 which may be obtained by writing to the Secretary of the United States Department of 

 Agriculture, Washington, D.C., or to his own congressman, 



