THE SERUM TREATMENT OF STREPTOCOCCUS INFECTIONS 763 



one time. Intravenous injections are not infrequently tolerated better than sub- 

 cutaneous injections. The horses may be bled several times during the course of 

 immunization and their serums tested. When the serum is to be used therapeutically, 

 the animals should not be bled in less than from ten to fourteen days after the last 

 injection was given. In view of the large doses required, a concentrated serum is 

 advisable (Heinemann and Gatewood 1 ) . Since trikresol has an inhibiting influence 

 on phagocytosis (Weaver and TunniclifT 2 ), the minimal quantity (0.2 per cent, or 

 less) should be used, or preferably no preservative at all. 



Second Method. Kolle prepares a polyvalent serum with cultures derived from 

 cases of erysipelas, puerperal sepsis, scarlet fever, etc. Their virulence is increased 

 from time to time by passage through rabbits. 



Horses are used for immunization purposes and all injections are given intra- 

 venously at intervals of a week. Cultures are grown on test-tubes containing a solid 

 medium, and immunization is started with half a culture, heated. The dose is 

 increased each week with an additional culture until it equals 16 cultures. Then 

 living and killed cultures are mixed, giving in one week 2 living and 14 killed cultures 

 and so on until 10 living and 6 killed cultures are given at a single dose. The horses 

 are bled two weeks after the last dose is administered. 



Standardization of Antistreptococcus Serum. There is at present no single 

 satisfactory method for standardizing these serums, although a satisfactory method 

 is a desideratum for testing serums placed on the market. In order to obtain an 

 approximate idea as to the value of a serum, the following tests may be employed: 



1. Protective Value. At the Serum Institute in Vienna a passed culture (one 

 used in the process of immunization) is selected, and that dose which will kill a mouse 

 at the expiration of or just preceding the end of four days is regarded as a single lethal 

 dose. In testing an antiserum 10 times this quantity of culture is used with decreasing 

 doses of immune serum injected twenty-four hours previously or simultaneously. 

 A normal serum is one of which 0.01 c.c. will afford protection, and 1 c.c. of such a 

 serum is said to be one immunity unit, i. e., it affords protection against 1000 lethal 

 doses of culture. 



2. Bacteriotropic Value. The technic of Wright or Neufeld may be employed 

 with a virulent culture and human leukocytes. Weaver and Tunnicliff have observed 

 better results when using one part of immune serum reactivated with nine parts of 

 fresh guinea-pig serum. 



3. Complement-fixation Tests. These tests may be employed with the bacterial 

 emulsion or autolysate used in immunization as the antigen. 



The serum should be kept in a cool, dark place. After a few months it loses 

 some of its protective value, and much of it on the market is worthless. 



Administration of Antistreptococcus Serum. It must be emphasized 

 here that } in order to obtain the best results, antistreptococcus serum must 

 be given intravenously. In an adult patient with a severe general infec- 

 tion from 30 to 100 c.c. of serum, diluted with an equal amount of sterile 

 normal salt solution, may be given in one dose. If improvement follows, 

 subsequent doses should be given subcutaneously or intramuscularly in 

 order to prolong the action of the serum. If no improvement follows in 

 from twelve to twenty-four hours, or if an acute exacerbation sets in, a 

 second dose should be given intravenously. Since the various manu- 

 1 Jour. Infect. Diseases, 1912, x, No. 3. 2 Jour. Infect. Diseases, 1911, ix, 130. 



