STREPTOCOCCUS INFECTIONS 249 



example, so as to have an approximative indicator at least for the 

 potency of the antiserum, this being then standardized against that 

 particular "animalized" strain. At the same institute that dose 

 of streptococci which will kill a white mouse at the expiration of or 

 just preceding the end of four days is designated as a single lethal 

 dose; but in testing an antiserum, ten times this amount is chosen 

 as the dose against which one unit of antiserum should afford pro- 

 tection. A simple normal serum is one of which 0.01 c.c. will afford 

 this degree of protection, and 1 c.c. of such a serum is said to con- 

 tain a single immunization unit, and 1 c.c. will accordingly protect 

 1000 mice against a single lethal dose each. The Vienna serum, as 

 it is now marketed, contains 20 to 40 units to the cubic centimeter. 



Dosage and Uses. Prophylactic Doses. For prophylactic pur- 

 poses, antistreptococcus serum has been recommended in connection 

 with scarlatina and the puerperal process, either by itself or in combi- 

 nation with the use of a vaccine. To prepare the latter, F. Meyer 

 suggests that a bouillon culture of a corresponding strain be obtained, 

 centrifugalized, the sediment washed repeatedly with saline, and 

 finally emulsified with a quantity of 0.5 per cent, carbolic acid in 

 saline, equal to the volume of the initial culture. The resultant 

 emulsion is killed off by heating for six hours at a temperature of 

 65 C., when it is tested bacteriologically and shaken overnight in a 

 shaking machine. This constitutes the finished vaccine, which does 

 not need to be counted out. The individual in question receives a 

 serum injection of 20 c.c., and at intervals of three days increasing 

 doses of the vaccine (0.1, 0.2, 0.4, 0.8, and 1.6 c.c.). 



Curative Dose. For curative purposes the serum has been used 

 in scarlatina, in severe streptococcus infections of the throat, in 

 erysipelas, in puerperal streptococcus infections, in chronic strepto- 

 coccus infections associated with tuberculosis and malignant growths, 

 in streptococcus endocarditis and arthritis, etc. In scarlatina the 

 treatment is indicated especially in those cases in which the throat 

 infection is at all severe, or in which the initial general symptoms 

 suggest the likelihood of a severe course. In cases of the first type 

 the injection of 50 to 100 c.c., given subcutaneously, and repeated 

 once or twice, if necessary, is usually sufficient, while in severe 

 systemic infections, when the blood examination frequently shows 

 the presence of large numbers of organisms, still larger doses, and 

 repeated even more frequently, are advocated. In cases of pro- 



