FORMATION OF DEFENSIVE FERMENTS 



of a 10 per cent, gelatine-peptone solution, and 2-5 c.c, 

 of normal salt solution (see fig. 2). 



0,30 



Hou 



>-.i 



(3) The dog in this experiment was given on 

 October 18, 3 c.c. of a 10 per cent, silk-peptone 

 solution by subcutaneous injection. On October 21 

 blood was taken. The serum split up both silk- 

 peptone (curve a in fig. 3), and gelatine (curve c in 

 fig. 3). At a temperature of 60 C. the serum became 

 inactive (curve b in fig. 3). 



\Ve may point out here that we thought it possible, 

 at first, that the phenomena observed by us might 

 have some connection with what is called anaphy- 

 laxy, or supersensibility. 7 By this we understand the 



7 Hermann Pfeiffer, of Graz, at about the same time as, and 

 independently of, ourselves, has demonstrated the existence 

 of proteolytic ferments in the blood plasma of sensitized 

 animals, after we had already established the fact of the 

 appearance of peptolytic ferments subsequent to the intro- 

 duction into the blood of disharmonious derivatives of 

 albumen, and had in this way systematically treated the 

 whole problem. The first experiments were made with 

 albumen. They have since been abandoned, because the 

 results of an alteration in rotation seemed particularly 

 ambiguous in cases where the serum of animals, treated pre- 

 viously with albumen, was brought into contact with albumen 

 or peptone. For this reason polypeptides are preferable for 

 reactions on ferments, as being compounds whose exact struc- 

 ture is known to us. 



