572 ABSTRACTS 



also to the fact that the organisms so grown are phagocyted in normal 

 serum. It is interesting to note that the variations in pneumococci 

 produced by treatment with immune serum do not persist after animal 

 passage. Reversion to the normal type takes place readily. — B. W. 



Further Observations on the Agglutination of Bacteria in Vivo. C. G. 



Bull. (Jour. Exp. Med., 1916, 24, 25-34.) 



Pneumococci, dysentery bacilU of the Shiga type, and Bacillus muco- 

 sus-capsulatus are agglutinated immediately when injected into the 

 circulation of actively immunized rabbits. Staphylococcus aureus and 

 albus, colon bacilli, meningococci, gonococci, and non-virulent pneumo- 

 cocci agglutinate in the circulation of normal rabbits. Bouillon cul- 

 tures of Bacillus avisepticus are highly toxic for both rabbits and dogs. 

 The fresh sera of these animals have no bactericidal action upon the 

 bacteria. Dog serum opsonizes the bacilli in vitro, and they are agglu- 

 tinated and opsonized in the circulation and organs of normal dogs. On 

 the other hand, this does not occur in connection with normal rabbits. 

 A very small quantity of culture produces a fatal septicemia in rabbits 

 but a subtoxic dose is without effect in dogs. The degree of aggluti- 

 nation and opsonization of bacteria within the animal body is inversely 

 parallel to the infectiousness of the bacteria for the host. — B. W. 



A Simple Method of Quantitative Determination of Complement Fixa- 

 tion. J. 0. HiRscHFELDER. (Jour. A. M. A., 1916, 66, 1386-1387.) 

 The author gives his technic for performing complement fixation 

 tests.— G. H. W. 



The "Delayed Negative" Wassermann Reaction. 0. M. Olson. (Jour. 



Lab. and CKn. Ned., 1916, 1, 704-705.) 



The "delayed negative" reaction differs from the original Wasser- 

 mann only in the method of reading the test. Instead of one reading 

 at the end of two hours, readings are taken at twenty minute intervals 

 while the tubes are in the incubator. 



By this method the progress of hemolysis may be observed, and the 

 relation of the time of reaction between the positive and negative con- 

 trols and the serum under test may be noted. 



Whenever hemolysis begins later and is slower in producing com- 

 plete lysis than the negative control, the serum under test is called a 

 "delayed negative" and is considered indicative of syphilis. — M. W. C. 



The Antagonistic Action of Negative Sera upon the Wasserman Reaction. 



A. W. Sellards and G. R. Minot. (Jour. Med. Res., 1916, 34, 131- 



147.) 



The authors report observations on the ability of normal negative 

 sera to antagonize the reaction between a positive syphilitic serum and 

 antigen. Working on the theory that, with a non-specific antigen such 

 as is now commonly used for the Wassermann, binding may result from 

 either an increase of specific complement-fixing antibodies, or a de- 



