VACCINE-THERAPY 149 



Antistreptococcic Serum. 



It has been proved that after injecting an emulsion of 

 devitalized streptococci into the circulation of a horse, and 

 following* this up by small and gradually increasing doses 

 of living bacteria, the time arrives when that animal's 

 serum has acquired high antimicrobic powers. Marmorek 

 was the first to demonstrate this fact ; and he also showed, if 

 the antistreptococcic serum thus obtained is injected into an 

 animal, and that animal is subjected to the action of viru- 

 lent streptococci, it will prove itself to be either completely 

 resistant, or, if the disease should develop, it will show itself 

 in an exceedingly mild form. 



It is most important to remember that there are many 

 strains of streptococci, and each may be equally virulent ; 

 and one can demonstrate this from their appearances easily 

 under the microscope. Take, for example, the plump, well- 

 nourished, globular-looking types one sees in a severe 

 attack of strangles, and compare them with the shrivelled- 

 up, small, almost oval-shaped, short, compressed chains as 

 seen in those cases of bovine endometritis. In making, 

 therefore, a satisfactory serum, a polyvalent serum is to be 

 preferred to a monovalent one. It is the experience of the 

 writer, in the cases where the virulence of the bacteria is 

 very great, that a combination of an autogenous vaccine 

 and a stock serum (polyvalent) gives much better results 

 than if either is used singly. 



In fact, so strongly do we hold this view now, that, given 

 a serious case with septicemic tendencies, we never think 

 of failing to combine the serum with the vaccine. 



In some strangles outbreaks the disease takes on a very 

 virulent form, and, in addition to manifesting local lesions, 

 extension takes place, probably through the lymphatic 

 system, to the mesenteric or mediastinal glands. 



Or some vital organ, such as the liver, kidneys, etc., 

 may become involved. When the blood-stream itself has 

 become invaded by the bacteria, a typical septicaemia has 



