114 VACCINE AND SERUM THERAPY. 



doses of killed and later living bouillon cultures of numerous 

 strains of streptococci recently isolated from patients. Several 

 months are required to immunize horses from which the immune 

 serum is to be obtained. After testing the serum for sterility it 

 is usually tubed in suitable syringes. 



The method of action of anti-streptococcic serum is little 

 understood. The serum contains agglutinins but these have not 

 been regarded of value in immunization. With the discovery of 

 bacteriotropins by Neufeld and Rimpau and opsonins by Wright 

 and Douglas new light has been thrown on the action of these 

 sera, for it has been found that in anti-streptococcic serum there 

 is present a specific substance which makes streptococci vulnerable 

 to ingestion by leucocytes. 



Standardization and determination of the amount of pro- 

 tective substances in anti-streptococcic serum has not been suc- 

 cessful, because the susceptibility of animals to streptococci varies 

 and because the method of protective action of the serum is little 

 known. Usually the dose injected is regulated according to cubic 

 centimeters of polyvalent anti-streptococcic sera. The potency 

 of this serum decreases relatively rapidly so that it ought not to 

 be used later than six months after the bleeding of the immunized 

 horse. 



Anti-streptococcic serum has been used especially in septi- 

 caemia, local infections following traumatism, streptococcic pneu- 

 monia, meningitis, rheumatism, erysipelas, pueperal sepsis, scarlet 

 fever, secondary infection complicating tuberculosis, and in fact, 

 in all streptococcus infections. 



The therapeutic and prophylactic results obtained by the use 

 of anti-streptococcic serum vary considerably and are apparently 

 dependent on various conditions, such as grade and kind of im- 

 munizing serum, day of disease on which injections are made, 

 amount of serum injected, virulence of infecting organism, and 

 determination of the invading organism. From the various re- 

 ports which have been received from clinicians who have used 

 these sera, there can be no doubt as to the beneficial results which 

 may at times be obtained from its use. In order that good results 

 may be obtained, however, it is essential that it be definitely 

 determined that the streptococcus is responsible for the diseased 

 condition, that a high grade of polyvalent serum be given early 



