Artificial immunity against toxins 389 



cerning the antihaemotoxins indicate also that these substances have 

 some other origin than the red blood corpuscles. 



This latter supposition appears to be in contradiction to Ransom's 1 

 very interesting researches on the haemolytic action of saponin, 

 carried out in Meyer's laboratory at Marburg. This glucoside, owing 

 to its property of fixing itself on the stroma of these corpuscles 

 dissolves the red corpuscles of many vertebrates. The cholesterin of 

 this stroma combines with the saponin, as the result of which the red 

 corpuscles become altered and allow the haemoglobin to diffuse. But 

 this same substance, cholesterin, which causes the poison to penetrate 

 into the red blood corpuscles, prevents the solution of these elements 

 when they are bathed in blood-serum. This fluid, in fact, acts as the 

 antitoxin to saponin and does so just because it contains cholesterin. 

 The cholesterin of the serum, fixing the saponin, prevents it from 

 affecting the red corpuscles, thus fulfilling the function of a well 

 fitted lightning conductor. On the other hand, when the cholesterin 

 of the stroma of these corpuscles is linked on to the saponin, it 

 renders them the disservice of a defective lightning conductor. The 

 accord between these facts and the postulates of Ehrlich's theory led 

 Ransom to suppose that in the haemolysins and antihaemolysins, [409] 

 cholesterin perhaps played a similar part. His experiments con- 

 vinced him that this was not the case. As it is generally accepted, 

 after Calmette's 2 experiments and according to Ehrlich's view, that 

 the alkaloids and the glucosides in general are incapable of setting up 

 the formation of antitoxins, we might regard the attempts to find an 

 antisaponin and to settle whether it is identical with cholesterin as 

 useless. But in regard to these delicate questions we must be careful 

 not to give too great weight to a priori arguments. It was believed 

 until quite recently that substances with very complex molecules, 

 such as the albuminoids, toxins and soluble ferments, must always 

 give rise to the production of antibodies in the animal ; whilst the 

 simpler substances whose chemical nature was better defined could 

 never lead to this. Facts acquired in recent years have led to a 

 modification of this view. In our fifth chapter we have already spoken 

 of the fruitless attempts of Ehrlich and Morgenroth to obtain certain 

 antifixatives. And yet the fixatives, as is shown by the results of 

 the researches of Bordet and myself, belong to the category of 

 substances which are quite capable of setting up the formation of 



1 Deutsche med. Wchnschr., Leipzig, 1901, S. 194. 



2 Ann. de VInst. Pasteur, Paris, 1895, t. ix, p, 244. 



