6 BULLETIN 340, U. S. DEPARTMENT OE AGRICULTURE. 



The inoculations should be made subcutaneously. Intravenous 

 injections as first employed by Sclavo are less effective. The potency 

 of the anthrax serum is in no way increased by this method of 

 immunization. Besides there exists the danger of emboli when in the 

 later stages of the immunization process larger amounts of culture 

 material have to be administered. Animals which have been treated 

 with 'subcutaneous injections will produce finally an anthrax serum 

 of remarkably high potency. 



As a rule the animals which have received one to two agar cultures 

 show a specific protective action of their serum, but for practical 

 purposes it is not advisable to use such a serum. Generally only 

 when the animals stand one-half to one mass culture is the potency 

 of the serum sufficiently strong. A similar condition is manifested 

 in animals used for the production of immune serums for other 

 diseases, the individuals showing a varying response to the injection 

 for the production of immune bodies, i. e., an animal will at times 

 produce a potent serum relatively early, whereas another with the- 

 same method of treatment will develop a serum of the same potency 

 only after a considerably longer preparatory treatment. Accord- 

 ingly, from observation it has been noted that sheep produce the 

 most potent serum, and in this species of animals the individual 

 differences are of almost no consequence, so that almost every animal 

 produces a good anthrax serum. Horses also produce a potent serum, 

 although single individuals may show great variations. The anthrax 

 serum from cattle is quite potent, but in its protective value it does 

 not equal horse and sheep serum. 



It is best to draw the blood 14 to 16 days after the last injection; 

 an earlier bleeding should be avoided. Not infrequently it occurs 

 that animals after an apparent recovery following the inoculation 

 reaction and after a period in which they are free of fever on the 

 eighth or ninth day suddenly develop a rise in temperature. This 

 has been established by Sclavo and Burow. Then, again, repeated 

 regular blood examinations showed that at this time and even later, 

 up to the tenth and eleventh days following inoculation, occasional 

 anthrax bacilli may appear in the blood of the animals in greater 

 numbers. 



The bleeding is carried out in the ordinary way, and the blood is 

 collected in large sterilized glass cylinders or similar receptacles of 

 about 2 or 3 liters capacity. Seven or eight liters of blood may be 

 drawn from cattle, about the same quantity from horses, and about 

 1 to 1-| liters from sheep. After 2 or 3 days another bleeding is 

 made. In this instance, however, only a small quantity of blood 

 should be drawn. The animals resist these operations very readily, 

 and after a lapse of 14 days they are ready for another injection, 



