258 REPORT OF THE COMMISSIONER 01' AGRICULTURE. 



we can scarcely hope that the winters in any considerable part of the 

 stock-raising section of the country will be sufficiently severe to prove 

 a permanent check to the extension of this contagion. 



It is proposed to continue the examination of this district across Arkan- 

 sas, Indian Territory, and Texas, to the Rio Grande Kiver, and it is believed 

 that a definite location of this line will be of great assistance to those en- 

 gaged in the live-stock industry in the whole southwestern part of the coun- 

 try. The mortality among thoroughbred cattle taken south of the border 

 line of the permanently infected district is so great that it has become a 

 matter of importance to buy animals which have acquired a certain 

 amount of immunity from this disease. It is believed by many breed- 

 ers that by establishing breeding farms just within the line of infection 

 that there will be a smaller mortality from the disease, and that the 

 animals raised under these conditions will still be able to resist its ef- 

 fects in a very perfect manner. Already such farms have been estab- 

 lished in Southeast Kansas and Southern Missouri, under the belief that 

 animals raised in this locality will prove insusceptible to the disease 

 when carried further south, but the great uncertainty which at present 

 exists with regard to the exact location of this line makes it extremely 

 doubtful if these farms have been correctly located. A number of ex- 

 tensive breeders who have a very intelligent idea of the nature and 

 effects of this disease have recently expressed to me their high appre- 

 ciation of the work now being done by the Department of Agriculture 

 toward establishing the boundary of this infected district. It is be- 

 lieved that definite knowledge in regard to this will relieve them from 

 many of the causes of embarrassment connected with the shipment of 

 thoroughbred cattle to the South. 



INVESTIGATIONS OF SWINE PLAGUE. 



In a communication of M. Pasteur to the Paris Academy of Sciences 

 (Comptes Piendus, 1883, p, 1163) it was asserted: 



1. That the microbe of swine plague is a dumb-bell micrococcus. 



2. That pigeons are very susceptible to the virus, and passing this 

 through a succession of these birds increases its activity. 



3. That rabbits are also susceptible, and passing the virus through 

 a succession of these animals attenuates it to such an extent that if pigs 

 are inoculated with it they only contract a slight illness which grants 

 them immunity from subsequent attacks. 



To these assertions Dr. Klein (Vet. Jr., 1884, July, p. 39) replies : 



1. That M. Pasteur has overlooked the true microbe, and that this is 

 a bacillus and not a micrococcus. 



2. That all of his (Klein's) inoculations of pigeons with virus taken 

 directly from diseased swine — virus which invariably produces the dis- 

 ease in swine and other susceptible animals — and with his artificial cul- 

 tures of the organism of swine fever, produced absolutely no effect, 

 either general or local. 



3. That it is impossible to say whether M. Pasteur's rabbits died of 

 swine fever or of septicemia, though he (Klein) had shown in 1877 that 

 rabbits are susceptible to swine fever when inoculated from material 

 directly derived from the pig. 



4. He adds in an addendum that he has recently satisfied himselt 

 that the artificial cultivation of the virus in the organs of mice or rab- 

 bits by inoculating these from diseased swine will produce a mild form 



