20 ANAPHYLAXIS AND ANTI-ANAPHYLAXIS 



other words, the more the serum is diluted the more 

 thermostable does the sensibiligen appear to be. 



If Rosenau and Anderson, and Doerr and Russ as 

 well, had carried out their sensitisation experiments 

 under the conditions we have indicated, they would 

 have seen that sensibiligen is in reality thermostable ; 

 that is to say, that sera adequately diluted, although 

 heated to ioo° C. for twenty minutes, preserve their 

 sensitising power in its integrity. 



If we have dwelt upon these experiments in some 

 little detail, it is because they shew how far the 

 physical state of the substance is important in ana- 

 phylaxis; we shall, moreover, see other examples of 

 it in the course of this account. 



Certain authors have sought to isolate in the pure 

 or almost pure state the sensibiligen contained in the 

 serum. For example. Gay and Adler^ believed that 

 it was possible to obtain it by fractional precipita- 

 tion of the serum with ammonium sulphate. In the 

 opinion of these workers sensibiligen would be found 

 in the pure state in the euglobulin. This latter sub- 

 stance would also be capable of sensitising the 

 animal in the space of four to five days, instead of 

 taking eight to twelve days. The euglobuhn, in its 

 quality of pure sensibiligen, would be deprived of its 

 vaccine and toxic properties peculiar to the whole 

 serum, as we shall see farther on. 



Numerous attempts have been made to deprive 

 serum of its sensitising function. In order to effect 

 this experimenters have tried the action of various 

 chemical products such as formaldehyde, hydro- 

 chloric acid, etc., upon sera. Without going into 

 detail on this point, we may say at once that every 

 one of these experiments has missed its aim; either 

 the reagents employed failed to destroy anything at 

 all, or else they made such profound alterations in 

 * Journal of Medical Research, xiii., 1908, p, 433. 



