16 BULLETIN 340, U. S. DEPARTMENT OF AGRICULTURE. 



manner. This procedure would greatly simplify the administration 

 of the serum and vaccine and, besides, the products would be in a 

 form least likely to deteriorate or become contaminated. 



The proteids containing the protective bodies of the serum have 

 also been successfully precipitated through fractional saturation of 

 the serum with ammonium sulphate, and further work along this 

 line is now being conducted. However, this work and the work on 

 the drying and concentration of the products are still in the experi- 

 mental stage, and it is our aim to properly work out a method most 

 suitable for immunization of animals in the field. 



CONCLUSION. 



1. Horses are suitable for the production of highly potent anthrax 

 serum. Serum of such horses should protect large animals in 10 c. c. 

 doses. 



2. The use of the serum-alone treatment is indicated in cases where 

 the infection has already occurred in a herd. Since the serum con- 

 fers only a passive immunity, it is advisable to revaccinate the herd 

 in from three to five weeks by the simultaneous method. 



3. The serum possesses great curative value. Depending on the 

 severity of the infection, the curative dose is from 30 to 100 c. c. ; the 

 injection to be repeated if necessary. 



4. For the simultaneous treatment a spore vaccine, carefully stand- 

 ardized, is preferable to the ordinary Pasteur vaccine. 



5. Spore vaccine should be employed also in preference to the 

 Pasteur vaccines for immunization with vaccine alone. This vaccine 

 has a decided advantage over the Pasteur, because of the possibility 

 of more accurate dosing and because of its better keeping qualities. 



6. Experiments with concentrated serum and dry spore vaccine 

 are very promising. This method would greatly simplify the vac- 

 cination process and also insure the product against subsequent con- 

 tamination and deterioration. 



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