8 4 



LECTURES ON IMMUNITY 



portional to its mass. This has been confirmed by Euler, 1 

 who digested glycyl-glycin by means of trypsin. 



Henri and Lalou 2 have also carried out some measure- 

 ments on the decomposition of amygdalin and salicin by 

 means of emulsin at 26 C. The readings were deter- 

 mined by means of a polarimeter. An example may be 

 given : 



The decomposition of the mixture is much slower than 

 the sum of the decompositions of the constituents. For 

 comparison the rates of decomposition of 4 per cent salicin 

 and of 1.25 per cent amygdalin under similar conditions 

 are given in parallel. The explanation of the difference 

 is evidently the same as that of the non-proportionality of 

 reaction and concentration, but it offers no more stringent 

 conclusions, regarding the combination of enzyme and sub- 

 strate, than does this latter circumstance. 



Weis 3 has carried out a great number of experiments on 

 the digestion of the protein from wheat by means of tryp- 

 sin or pepsin (extract of malt). A great interest is attached 

 to those experiments in which the quantity of protein was 

 varied. In the experiments on digestion cited above, the 



3 Euler: Arkiv fur Kemi, 2. No. 31, p. 8, Stockholm, 1907. 

 2 Henri and Lalou : C. R. de la Soc. de Biol. 55. 868 (1903). 

 8 Fr. Weis : Meddelelser fra Carhbtrg-Laboratorict, 5. 127 (1903)- 



