( 1005 ) 
have directly opposite effects on trypsin and on trypsinogen, as [| 
gathered from a great many experiments. Whilst on the one hand 
trypsimogen can be activated *) by the action of bacteria, on the 
other hand the action of trypsin is greatly impeded by bacteria (or 
perhaps by the decomposition-products of albumen at the joint 
action of trypsin and bacteria. The pancreatic-juice experimented 
upon containing comparatively little trypsinogen and much trypsin, 
the antitryptic action of the bacteria prevailed in this ease upon its 
activating influence, which also appears from the fact that in 4) 
and 1) the albumen-digestion is still the same after 24 hours, whilst 
after 48 hours (when all the trypsinogen in 4) could be expected 
to have passed into trypsin) it is considerably less in 4) than in 1). 
Obviously this experiment gives support to the opinion that the 
influence of micro-organisms, in experiments relating to the activa- 
tion of trypsinogen (and [ may add by the way: likewise in expe- 
riments on antitryptic factors) should by no means be disregarded. 
The condition that the action of bacteria must be effectually 
obviated in such experiments, e.g. when studying the effect of 
calcium-salts on the activation of trypsinogen, forms one of the diffi- 
culties I alluded to just now. The more so, as it stands to reason 
that in experiments with Ca-salts no NaFl may be used, which we 
ean also gather for instance from 7) Table I. As we see the diges- 
tion in 7) is very inconsiderable. This must be attributed to the Fl. 
of the Nall having formed in this case insoluble CaFl, with the Ca 
of CaCl,. The precipitate CaFl, had sunk to the bottom of the test- 
bottle, carrying part of the albumen of the pancreatic juice with it. 
Hence the Mett-tubes had got enclosed in a thick precipitate of 
CaF], and pancreatic albumen, in consequence of which the trypsin- 
action on the Mett’s albumen-columns could of course not assert 
itself so well. 
Finally on comparing in Table I the numbers 5) and 6) with 1) 
and 2), we might at first sight be inclined to assume that under 
the influence of CaCl, trypsinogen had been activated, the digestion 
in 5) and 6) being considerably greater than in 1), and as great, nay 
even somewhat greater than in 2). On second thoughts I arrived at 
the conclusion that in this case not merely the actwating effect of 
CaCl, had to be considered, that at any rate there must also be 
other reasons for the greater digestion in 5) and 6). Indeed it appears 
from 2) that in this case the amount of trypsinogen could only be 
1) For further ‘particulars on this subject see an article of mine in the Archiv. 
fir Anat. und Physiologie 1904 p. 343. 
66 
Proceedings Royal Acad. Amsterdam. Vol. XIII. 
