XLV. THE POWER OF NORMAL SERUM TO DEFLECT 



COMPLEMENT. 1 



By Dr. HANS SACHS, Member of the Institute. 



IN a previous paper 2 the writer discussed the action of certain 

 substances in normal serum which, according to Pfeiffer and Fried- 

 berger, 3 exerted antibacteriolytic effects. A recent study by Gay 4 

 leads me to take up the subject anew. Pfeiffer and Friedberger 

 had shown that normal sera which by themselves possessed no 

 antibacteriolytic properties, acquired such properties if they were 

 previously digested with bacteria. Moreover the sera obtained 

 by this treatment exert specific antilytic properties, that is to say, 

 a serum digested with cholera vibrios protects only chlorea vibrios 

 against bacteriolysis, etc. I thereupon studied the same condi- 

 tions by means of hcemolytic test-tube experiments, and was able 

 to confirm the author's findings. Rabbit serum digested with 

 sheep blood-cells exerts antihaemolytic effects directed practically 

 entirely against the haemolysis of sheep blood. My conception 

 of the mechanism of this action differs from that of Pfeiffer and 

 Friedberger only in that I do not regard the inhibiting substances 

 concerned as new, hitherto unknown bodies. I believe that this 

 inhibiting effect, at least in the case of hsemolysins, is due to ambo- 

 ceptors, acting, as they often do, like anticomplements. That 

 such amboceptors occur in normal serum is well known from nu- 

 merous observations. At any rate, the views of Pfeiffer and Fried- 

 berger and my own probably agree in regarding the inhibiting 

 substances in the serum as preformed, their action in native serum 



1 Reprinted from Centralblatt f. Bacteriologie, Vol. XL, 1906. 



2 Sachs. Deutsche med. Wochenschrift, No. 18, 1905. 



3 Pfeiffer and Freidberger, ibid. No. 1, and also No. 29, 1905. 



4 Gay, Centralblatt Bacteriologie, Orig. XXXIX, 1905. See also Bordet- 

 Gay, Collected Studies, Wiley & Sons, 1909. 



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