VETERINARY MEDICINE. 585 



Undfer the last head, which includes a consideration of the several metliods 

 and vaccines thus far proposed for producing immunity, the author summarizes 

 particularly his experience with the Pasteur method, the principal drawback 

 to which seems to be the length of time required, which in the event of an 

 outbi'eak is a serious disadvantage. AVith the idea of finding a method whereby 

 an immediate imnuniity could be established in existing outbreaks, or whereby 

 imnuuiity could be produced under ordinary conditions in a shorter time than 

 with the Pasteur treatment, the author conducted some experiments as a result 

 of which he announces that he has produced an antibacterial serum by highly 

 immunizing sheep by repeated inoculations, first of attenuated anthrax bacilli, 

 and following these by inoculations of the most virulent races of the bacilli in 

 increasing doses until the animal would withstand fifty thousand times the 

 minimal lethal dose, with impunity. Such a serum will protect a sheej) against 

 an otherwise mortal dose of bacilli and produce an immediate immunity. . . . 

 The serum will confer a passive immunity inmiediately, and thus protect the 

 animal against fatal infection over the i)oriod which is necessary for the 

 vaccine to confer an active immunity. AA'here an animal which has been pro- 

 tected by the serum becomes infected with an otherwise fatal bacillus, the 

 results of this infection will be the production of a much stronger immunity 

 than the vaccine and serum would confer. 



Pyocyanase made after the method of Emmerich and Loew gave some good 

 results when tested upon rabbits, but failed upon sheep. Anthraxin, which 

 is made in a manner similar to mallein and tuberculin, was tested in regard 

 to its eflScacy with the result that it was not found to possess any immunizing 

 properties. Some tests were also made with a commercial vaccine in pill 

 form, but immunity could not be obtained with it. 



"Anthraxase, prepared by the writer after the same general method used in 

 producing pyocyanase, was without protective or curative properties, although 

 it produced high fever when injected into rabbits and sheep subcutaneously." 



Anthraxoin, consisting of a turbid suspension in carbolized normal salt solu- 

 tion of dead sporeless anthrax bacilli, was apparently useless in protecting 

 sheep against anthrax when used similarly to the Pasteur vaccine. 



A single vaccine, which had for its object the production of immunity in 2 

 weeks and thus cutting down the necessary period by 2 weeks, was made by 

 the author by incubating a virulent bacillus for about 18 days at 42 to 43° 

 C. " Such a culture, which will kill guinea pigs in about a week, thus holds a 

 position between the two vaccines of Pasteur in strength. With it sheep were 

 vaccinated and after 12 days withstood an otherwise fatal infection with 

 virulent bacilli. That the immunity was not in all cases sufficiently strong 

 was evidenced by the death now and then of a sheep when tested with virulent 

 bacilli." 



Along with the above investigations for studying the biology of the causative 

 organism and the general sanitary aspects of the subject, it was decided to 

 test the efficacy of freshly-prepared Pasteur vaccines, as it was believed that 

 some of the bad results that have been reported as following the use of Pasteur 

 vaccine were due to carelessness on the part of those preparing and using it. 

 Vaccines 1 and 2, prepared by the author, were therefore submitted to prac- 

 ticing veterinarians of the State of Delaware to be used on receipt, the vaccine 

 No. 2, however, not being shipped until 12 days after vaccine No. 1. The results 

 of observations for 2 years indicated that the use of fresh vaccines from bac- 

 teria which had been incubated for from 4 to 5 days or until the bacteria 

 sporulated is a good procedure to follow. The author believes that vaccine so 

 prepared will remain active for several months. 



