MULTIPLICITY OF ANTIBODIES IN NORMAL SERUM. 591 



binations, so that even when two species of blood-cells were 

 added at once, the agglutinating power for these could be reduced 

 to nil while the power for the remaining species of blood was unim- 

 paired. We see, therefore, that the results are entirely similar to 

 those obtained with the haemolysins and bacteriolysins; the 

 agglutinating power of normal serum on different species of cells is 

 due to separate and distinct substances contained in the serum. 



In addition to the foregoing we may also consider for a moment 

 those antibodies which act, not on bacteria or blood-cells, but 

 on ferments and toxins, in other words, the antitoxins and anti- 

 ferments. These bodies are not known directly, but only indi- 

 rectly by their neutralizing effect; we know little about their occur- 

 rence in normal serum. Landsteiner us), citing also the older 

 literature, found antitryptic substances in normal rabbit, guinea- 

 pig, and ox serum. Morgenroth do) found antibodies against 

 rennin and against cynarase in the serum of normal goats and 

 horses. By specific immunization this investigator was able to 

 show that rennin and cynarase were two distinct ferments, and 

 that the antirennin of normal serum was distinct from the normal 

 anticynarase. Morgenroth found that the relative amounts of the 

 two antibodies differed in two horse sera which he investigated. 



The existence of normal antitoxins has also been reported. 

 Meade Bolton, and later Cobbett (6) found that a considerable 

 proportion of normal horses had diphtheria antitoxin in their 

 serum, and that the amount of this was very variable. Wasser- 

 mann d8) found that not a few normal human individuals had 

 diphtheria antitoxin in their blood. Ehrlich (7) encountered a 

 normal horse serum which contained an antibody against teta- 

 nolysin, and Krauss (12) found normal horse serum effective against 

 a number of hsemolysins. In a paper which Dr. Wechsberg and 

 I hope soon to publish, it will be shown that we have constantly 

 found, in normal human serum, an antibody against staphylotoxin. 



In view of the fact that horse serum protects rabbit erythro- 

 cytes against tetanolysin, staphylolysin, and other hsemolysins, 

 Krauss concludes that the protective action is due to a single 

 substance in horse serum, and then concludes further that these 

 hsemolysins differ only quantitatively and not qualitatively. A few 

 exact quantitative experiments would have convinced Krauss that 

 this assumption of the non-specificity of haemolysins is absolutely 

 incorrect. It can be shown that an antistaphylolysin, artificially 



