ADAPTATION OF PANCREAS 103 



15*64 per cent, of nitrogen and lactosazone 10'41 per cent. The value 

 13'93 which was obtained in Exp. IX points to the presence of a 

 mixture of glucosazone and lactosazone. (It may be here stated 

 that Kjeldahl's method of estimating nitrogen is not applicable to 

 osazones. Glucosazone prepared from glucose gave 10'7 per cent, nitrogen, 

 and lactosazone from lactose gave 77 per cent.) 



One must therefore conclude with Bierry that the statements of 

 Weinland and Bainbridge were founded on fallacious methods of 

 experiments, and that under no circumstances is there any adaptation 

 of the activity of the pancreas to the presence of lactose in the food. 

 The general importance of such a conclusion I have already indicated. 

 The ideas of Pawlow with regard to the power of adaptation possessed 

 by this gland are founded on the results of Vasilieff and of Walther 

 which, however, as Bainbridge showed, do not prove his point as 

 regards lipase, and must be unreliable as regards the trypsin from the 

 fact that at the time the experiments were made the importance of 

 enterokinase for the activation of the juice was yet unknown. Popielski, 

 a former pupil of Pawlow, has himself concluded that there is no quali- 

 tative adaptation in the pancreas, but that the composition and 

 amount of this secretion is determined solely by the intensity and 

 duration of the stimulus (or as we should now express it, the amount of 

 secretin produced in a unit of time and the duration of its in-flow into 

 the blood). My experiments therefore would incline us to accept 

 Popielski's view, or at least to require further evidence for the qualita- 

 tive adaptation of the pancreas to the food-stuffs. 



BEFERENCES. 



1. E. Fischer and W. Niebel. Sitzber. Akad. Wiss. Berlin, 1896, p. 73. 



2. P. Portier. Compt. rend. Soc. Biol. 1898, v. p. 387. 



3. E. Weinland. Zeit. f. Biologie, xxxvm. p. 607. 1899. 



4. F. A. Bainbridge. This Journal, xxxi. p. 98. 1904. 



5. H. Bierry et Gmo. -Salazar. Compt. rend, cxxxix. p. 381. 1904. 



H. Bierry. Compt. rend. Soc. Biol. LVIII. pp. 700, 701. 1905. Compt. rend. 

 CXL. p. 1122. 1905. 



6. E. Weinland. Zeit. f. Biologie, XL. p. 386. 1900. 



7. G. Patein et E. Dufau. J. Pharm. Chim. xv. p. 221. 1902. 



8. E. H. A. Plimmer and W. M. Bayliss. This Journal, xxxni. p. 439. 1906. 



The expenses of this Besearch were defrayed by a Grant from the Government Grant 

 Committee of the Koyal Society. 



