BIOLOGICAL THERAPEUTICS 549 



A tetanus antitoxic unit is ten times the least amount of serum 

 which saves the life of a 350-gram guinea pig for 96 hours against the 

 official test dose of a standard toxin. If the serum is found of desired 

 potency the animal is bled from the jugular vein. The blood is allowed 

 to clotj the clear serum which separates is tested for sterility and after 

 the addition of a preservative it is filled into containers ready for use. 



The preventive treatment with antitoxin has proved effective beyond 

 any doubt and is always successful, provided it is undertaken early in 

 the period of incubation. This treatment consists of the injection of 

 tetanus antitoxin under the skin after an injury of any kind or after 

 operations. It is advisable to inject animals with antitoxin in all cases 

 when there is the slightest danger of tetanus developing. When the 

 antitoxin is not administered for four days or more after inoculation, the 

 result is uncertain. The prophylactic dose is 500 units during the first 

 seventy-two hours after inoculation; after that it should be increased 500 

 units for each twenty-four hours that have elapsed since 'probable inocu- 

 lation. 



Unlike many other biologic products, in tetanus antitoxin it is pos- 

 sible to establish accurately the number of units contained per mil of the 

 antitoxin and thereby we can always safely establish a uniform dose for 

 the protection of animals. The curative action of tetanus antitoxin is 

 very problematic, even excessively large doses at times failing to relieve 

 the affection in the slightest degree. This, however, can be readily ex- 

 plained by the pathogenicity of the tetanus toxin which, when once the 

 disease is establised and is progressing, becomes anchored in the nerve 

 cells, producing there morbid changes that can not be remedied. 



White Scours in Calves. 



White scours is an acute infectious disease of new-born calves which 

 in the majority of cases develops as a persistent diarrhea and loss of 

 strength, finally resulting in death. 



In every country in which stock breeding has been highly developed 

 the mortality in young animals from white scours is very large. Calves 

 in the first few days of their lives are especially threatened, but even 

 later fatal cases may occur. 



White scours is caused by specific pathogenic germs. The infection 

 as a rule is taken up by the mouth. In some cases, however, the germs 

 may enter the body through the navel. Investigations have conclusively 

 established that the great majority of outbreaks are due to an infection 

 with virulent strains of colon and para-colon bacilli; also that the newly 

 born calves are susceptible to infections through the digestive tract with 

 other .germs. The germs, which are persistent and diflScult to eradicate 

 from infected premises, are responsible for the losses of the calves. 

 Fortunately, investigators in Denmark succeeded in producing a highly 

 potent serum from horses which when injected into exposed calves will 

 prevent the disease, or in case the infection is already established, it 

 exerts a very favorable action upon the course of the disease. That is, 

 the serum has proved to possess, aside from its preventive action, also 

 great curative value. 



Anti-white scours serum is prepared by consecutive intravenous in- 

 jections of horses witlrn«B9«ETOjS,^tc«{OS,fif/«|^on and other germs which 



