EXPERIMENTS IN VACCINATION AGAINST ANTHRAX. 

 Hyperimmunization of horses Nos. J/8 and 96. 



Date. 



Amount of virus given each horse. 



Result. 



1914. 

 Sept. 29.... 



0.01 loopful. 



Oct. 24. 

 Nov. 15 

 Dec. 9.. 



Dec. 29. 

 Jan. 19. 

 Feb. G.. 



Mar. 5. 



Apr. 19. 

 Apr. 28. 

 May 11. 

 May 24. 

 June 12. 



1 loopful 



10 loopfuls 



5 c. c. of an emulsion, representing one- 

 half growth of agar culture. 



20 c. c. of emulsion, representing washing 



of growth from 2 agar cultures. 

 30 c. c. of emulsion, growth from 8 agar 



cultures. 

 40 c. c. of emulsion, growth from 2 mass 



cultures from flasks, surface area 6 by 



2-} inches. 



50 c. c. of emulsion, growth from 4 mass 



cultures from flasks, surface area 6 by 



2k inches. 

 50 c. c. of emulsion, growth from 8 mass 



cultures from flasks, surface area 6 by 



2£ inches. 



do 



do 



do 



do 



do 



No apparent reaction in horse 48. riorso 

 96 developed anthrax at point of inocula- 

 tion; large swelling; edema of neighbor- 

 ing tissue. Persisted about one week. 



No noticeable reaction in either animal. 

 Do. 



Horse 48 showed a temperature of 102.2° 

 the following day; horse 96, 101°. Both 

 animals developed a small, hard nodule 

 at point of inoculation. 



Both animals developed small abscess at 

 point of inoculation. 



No reaction. 



Slight reaction in horse 96. Horse 48 

 showed quite an intensive reaction, devel- 

 oping a large swelling at point of inocu- 

 lation; persisted several days. 



No apparent reaction. 



Slight local reaction in each case. 



Do. 



Slight rise in temperature in both eases. 

 Slight temperature and local reaction. 



Do. 

 Slight local reaction. 



In the above work four strains of anthrax bacilli were used, known 

 to us as "Davis," "6071," "Burt," and "Boener"— the first two 

 strains being highly virulent types and the latter two very much 

 weaker. In all cases where the larger amounts of the virus were 

 given the injections were made at 4 to 6 different points in order to 

 minimize abscess formation. 



. It might be well also to state here that the irregularity in the time 

 between injections was due to the fact that this work was interfered 

 with by the outbreak of foot-and-mouth disease in this country, and 

 for this reason it was also impossible to subject the blood to periodical 

 tests to ascertain its immunizing value at the different intervals 

 between injections. Experience proved that horses may produce 

 highly potent serum following the injection of the first or second 

 mass cultures. It is therefore advisable to subject the blood of the 

 animals to periodical tests for potency throughout the course of 

 immunization. 



On June 25, 1915, 6 liters of blood were drawn from each horse 

 into the glass bleeding cylinders previously described. Since this 

 date these animals have been bled regularly, 6 liters being taken 

 from each horse, and an injection of virus made in the intervals 

 between bleedings. 



SERUM TESTS. 



In standardizing our serum, that taken from each horse was tested 

 separately. The following procedure was carried out: Three series 



