BACTERICIDAL PROPERTIES OF BLOOD SERUM 167 



bovine serum. This second sensitizer is, however, superfluous. Its 

 presence is by no means necessary for the experiment. When this 

 sensitization is effected the corpuscles are then in condition to fix 

 the horse alexin. This alexin, however, has only slight hemolytic? 

 power. But once the corpuscles have become sensitized and laden 

 with alexin they are modified in their properties of molecular ad- 

 hesion to such an extent that they become able to attract a colloidal 

 substance of bovine serum, which unites with them. The adhesion 

 of this new substance produces two results : it causes the blood 

 corpuscles to be more easily destroyed by alexin and also agglutinates 

 them energetically. Consequently, a powerful clumping, followed 

 by hemolysis, is observed." 



Bordet and Gay, therefore, assume that the action of the bovine 

 serum is due to a new substance which they speak of as "bovine 

 colloid." This substance resists heating to 56 C., is probably al- 

 buminous, and has the property of uniting with cells that are laden 

 with sensitizer and alexin, but remains free in the presence of nor- 

 mal or merely sensitized cells. 



They fortify this opinion by showing experimentally that the 

 "colloid" is removed from bovine serum by absorption with sensi- 

 tized bovine corpuscles which have been treated with horse alexin. 60 



Bordet and Streng 61 later studied this "colloid" more thor- 

 oughly and have suggested for it the name "conglutinin." Streng 62 

 later showed that the agglutinating action of this substance could be 

 shown not only for sensitized and "alexinized" red blood cells, but 

 also for similarly treated bacteria, and that conglutinins were pres- 

 ent not only in bovine serum, but in that of goats, sheep, antelopes, 

 and a number of other herbivores, but apparently absent in cats, 

 dogs, guinea pigs, and birds. 



The body described by these workers as conglutinin is probably 

 identical with a similar heat-stable serum component reported by 

 Manwaring 68 and called by him "auxilysin." 



60 Browning (Wien kl. Wochenschr., 1906) had shown that horse alexin 

 may be absorbed by sensitized beef cells without causing hemolysis. 



61 Bordet and Streng. Centralbl. f. Bakt., Orig. Vol. 49, 1909. 



62 Streng. Zeitschr. /. Immunitatsforsch., Orig. Vol. 2, 1909, p. 415. 



63 Manwaring. Centralbl. f. Bakt., 1906 ; Orig. Vol. 42. 



