ANTIBODY OF INTESTINAL WORMS. 483 



activation of the pancreatic juice. It is well known that enterokinase in 

 alkaline solution is rapidly destroyed at 37 C. ; Dastre and Stassano 

 guarded against this source of error by omitting the usual '5/ sodium 

 carbonate when mixing the enterokinase and worm extract. But their 

 worm extract contained 2/o sodium fluoride. Sodium fluoride is dis- 

 tinctly alkaline, and is itself sufficient to destroy enterokinase as the 

 following experiments show. 



Enterokinase solution was prepared in the way already described. Some was kept 

 just as prepared (Ek.). To the rest was added sodium fluoride up to 2/ (Ek Na ) . The 

 worm extract used was neutral. The following mixtures were then made : 



Gel. digested in mm. 

 after 16 hours. 



/ ( -3 c.c. Ek Na + 1 c.c. W) + 1 c. c. P J = 3 -0 

 ( -3 c.c. Ek Na + 1 c.c. H 2 0) + 1 c.c. PJ = 5-0 



A 



at 15 C. 

 for 2 hrs. 



(3 c.c. Ek Na ) + l c.c. PJ + 1 c.c. W = 3-0 



B 



at 37 C. 

 for 2 hrs. 



(3 c.c. Ek + 1 c.c. W) + l c.c. PJ = 3-0 



(3 c.c. Ek + 1 c.c. H 2 0) + l c.c. PJ = 5"5 



\(-3c.o. Ek) + l c.c. PJ + 1 c.c. W = 3-0 



( -3 c.c. Ek Na + 1 c.c. W) + 1 c.c. PJ = 



( -3 c.c. Ek Xa + 1 c.c. H 2 0) + 1 c.c. PJ = 



(3 c.c. Ek Na ) + l c.c. PJ + 1 c.c. W = 



(-3 c.c. Ek + 1 c.c. W) + l c.c. PJ = 3-5 



(3 c.c. Ek + 1 c.c. H 2 O) + 1 c.c. PJ = 5'0 

 (3 c.c. Ek) + l c.c. PJ + 1 c.c. W = 3-0 



The brackets indicate that their contents have been kept together for 2 hours and then 

 the substances outside the brackets added. In series A the substances in brackets were 

 kept at 15 C. for 2 hours. In series B the substances in brackets were kept at 37 C. for 

 2 hours. Gelatine tubes and toluol were added to all and the amount of digestion 

 measured at the end of 16 hours. 



From this we see that activation occurs in all the tubes except 

 those in which the sodium fluoride enterokinase had been kept for 

 2 hours at 37 C. Dastre and Stassano's fundamental experiment 

 is thus inconclusive ; enterokinase exposed to the action of worm extract 

 for some time, even at 37 C., will activate pancreatic juice unless 

 destroyed by substances like sodium fluoride before the pancreatic 

 juice has been added. It is not permissible, therefore, to interpret the 

 experiments which follow this one in their paper arid which are in- 

 tended to confirm it, by assuming, as these observers have done, the 

 existence of antikinase in the worm extract; nor, indeed, is it necessary, 

 since all the phenomena recorded can be accounted for quite satis- 



