BIOLOGICAL PRODUCTS (VETERINARY). 
G71 
Vaccines. 
Anthrax Vaccine. Probably the first biological product used 
to any extent in veterinary medicine was Pasteur’s Anthrax Vac¬ 
cine. Pasteur in 1880-82 elaborated a method by which a mild 
form of anthrax could be given to an animal, which rendered 
them resistant to a subsequent inoculation with the specific viru¬ 
lent bacteria. He found that the continued growth of the anthrax 
organism at 42-43 degrees caused them to lose their ability to 
produce spores and also gradually to lose their virulence. This 
method, but slightly modified, is probably the most important at 
present. It is a double vaccine, that is, it consists of two strengths 
of virus, No. 1 being weaker than No. 2. In the preparation of 
the product the anthrax organisms are grown on agar or in 
bouillon at a temperature of 42 degrees for a period ranging from 
10 to 20 days. In the case of vaccine No. 1, it is usually incu¬ 
bated about 20 days. The resultant growth of the organism is 
then suspended in normal salt solution, or other liquid and tested 
for activity and safety. Mice, guinea pigs and rabbits are used 
in these tests. A satisfactory test should show that vaccine No. 
1 in small doses should kill mice, but not guinea pigs or rabbits. 
Vaccine No. 2 in the same dose should kill mice and guinea pigs, 
but not rabbits. 
In administering the vaccine, about 1 c.c. of vaccine No. 
1 is injected subcutaneously. Ten or fifteen days later the 
same amount of vaccine No: 2 is given. The vaccine should be 
used only on healthy animals, for if an animal is infected at the 
time of treatment, the vaccine being a virus, will tend to aggra¬ 
vate the condition and result fatally. Not infrequently the vac¬ 
cine will producer severe or fatal reaction in a normal animal. 
The results from the use of this vaccine indicate that it is of great 
value in dealing with anthrax, if properly prepared and admin¬ 
istered. The fact, however, that it is an attenuated but living 
virus, should always be kept in mind, for by its promiscuous and 
reckless use it may be the means of spreading the disease instead 
of curbing it. 
