STREPTOCOCCUS INFECTIONS 257 



alent 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 matte* 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 w r ould 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 anti- 

 sera 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 organ- 

 isms is followed by a relatively insignificant hyperleukocytosis and 

 phagocytosis, while the organisms multiply without any very evident 

 restraint, the treated animals show exactly the opposite picture, 

 i. e., extensive hyperleukocytosis and phagocytosis without evidence 

 of multiplication. The same can be shown outside of the body, 

 directly under the microscope; for whereas in the presence of normal 

 serum, washed leukocytes will scarcely take up any virulent strepto- 

 cocci, they do so readily when in contact with immune serum. 



Whether or not bacteriolytic processes also play a role in the 

 protection of the animal with suitable immune sera is still a matter 

 of dispute. Antitoxins, on the other hand, certainly are not present. 



Preparation and Standardization. The preparation of the anti- 

 streptococcus sera is conducted essentially on the same lines as that 

 17 



