STREPTOCOCCUS INFECTIONS 239 



which the passage had been conducted, might still be inactive in 

 the human being. In such an event, animal passage would have to 

 be omitted, and a monovalent or polyvalent serum prepared by 

 immunizing directly with strains that had been obtained from human 

 beings (sc., with cultures made from human sources only). 



Both possibilities have indeed been considered and practically 

 tested. Denys and van der Velde thus prepared a polyvalent 

 serum from a number of different strains, whose virulence had been 

 further increased by animal passage, but this serum also has fallen 

 into oblivion, which suggests that subsequent investigations did not 

 support the favorable reports which first followed its introduction. 

 Tavel, Krumbein and Paltauf, on the other hand, prepared polyvalent 

 sera from different human strains without animal passage, and 

 Menzer and Moser monovalent strains which had likewise not 

 been passed through animals, while Aronson attempted a combined 

 procedure making use of passed and unpassed organisms conjointly, 

 both in the form of monovalent and polyvalent preparations. At 

 the present time practically all these products are in use, and while 

 they are unquestionably efficacious in the animal experiment, the 

 clinical evidence is still rather against than in favor of their real 

 value. This suggests the possibility, of course, that clinicians may 

 not apply the sera as promptly in streptococcus infections as is 

 done in diphtheria, and as a matter of fact there is a good deal of 

 truth in this criticism. That this factor may actually be one of 

 moment is suggested by the fact that the best results have thus far 

 been obtained in scarlatina, where the diagnosis is reached at an 

 early date, and where the serum can be conveniently and system- 

 atically tested. In the other streptococcus infections the bacterio- 

 logical diagnosis is frequently not made at all, or it is delayed 

 until it would seem unreasonable to expect any favorable result. 

 Here, as elsewhere, in serum therapy, the clinician should bear in 

 mind that the greatest good will only be accomplished, if the various 

 antisera are used early, in sufficient quantity, and usually in repeated 

 doses. 



Mode of Action. Regarding the mode of action of the various 

 antistreptococcus sera, it would seem that this is to a great 

 extent bacteriotropic in character, for whereas in unprotected 

 animals an intraperitoneal inoculation with an appropriate number 

 of organisms is followed by a relatively insignificant hyperleuko- 



