The Value of Virulent Salt Solution in the Production of Antihog-Cholera Serum by the Intravenous Method

Abstract

Craig1 first suggested the use of virulent salt solution in the manufacture of antihog-cholera serum. Its use also received attention from Robbins.2 Their work indicates clearly that salt solution made virulent by passing through the peritoneal cavity of virus pigs can be injected subcutaneously into immune hogs in sufficient quantities to produce a potent antiserum. The intravenous method of serum-production is more widely used, but up to this time no systematic attempt has been made to use virulent salt solution in the course of hyperimmunizing by this method. The necessity of employing large amounts of virus in the production of antihog-cholera serum of high potency by the subcutaneous method has prevented its general adoption. The cost of producing antihogcholera serum by the intravenous method of injection, aside from other desirable features, is much less. This is quite generally conceded inasmuch as it requires about one-half the volume of blood virus if an immune animal is to be rendered hyperimmune by an initial dose of virus. Since the cost of serum is dependent upon the cost of the virus, any method which will increase the quantity of virulent material to be obtained from a single virus pig is therefore a factor in reducing the cost of serum. No doubt large quantities of virus are retained in the bodies of virus-producing animals, which under the present method are cremated. Attempts to remove the virus from the musculature and organs in sufficient quantities to render an animal hyperimmune following injection have not been consistently successful thus far. There exist no means of determining the degree of virulence of a given virus other than that indicated by illness following its injection into susceptible shoats and by the potency of the antiserum produced by its use in hyperimmunization. If by the use of virulent salt solution