CHEMICAL BASIS OF THE ANIMAL BODY. 57 



The amylolytic enzyme of the pancreas. 



The secretion of the pancreas is even more active than saliva in 

 effecting the hydrolysis of starch l . This property is dependent upon 

 the presence in this secretion of an enzyme which in many ways 

 closely resembles ptyalin, but differs from it markedly in its greater 

 power of effecting a more complete decomposition of the starch than 

 can ptyalin. Under ordinary conditions the only sugar formed by the 

 action of ptyalin on starch is maltose; if however the action is pro- 

 longed small amounts of dextrose may, it is stated, also make their 

 appearance as the result of the further action of the enzyme on the 

 first-formed maltose 2 . But this is by no means quite certainly the 

 case, and without doubt no dextrose is obtained during a digestion of 

 moderate duration. The pancreatic enzyme on the other hand not 

 only rapidly converts starch into maltose, but further converts this 

 maltose into dextrose in considerable quantity during a digestion of 

 relatively short duration in comparison with that required for its 

 production, by the action of ptyalin 3 . The secretion of the pancreas 

 is of extremely complicated composition and contains in addition to the 

 amylolytic at least two other well characterised enzymes; from these 

 the former has as yet been only very imperfectly separated, so that 

 scarcely anything is known of its chemical nature as distinct from its 

 converting powers. According to von Wittich the amylolytic enzyme 

 is separable from the others by treating the gland with ether and 

 alcohol before its extraction with glycerine, to which reagent it then 

 yields only the amylolytic enzyme 4 ; Hufner however obtained a 

 mixture of enzymes by von Wittich's method 5 . Experiments on the 

 separation of the enzymes have also been made by Danilewsky 6 and 

 Paschutin 7 , but the most successful outcome of any method which may 

 be employed simply results in the production of an extract which 

 is preponderatingly amylolytic but is by no means free from the other 

 enzymes. An active amylolytic extract is best prepared by Roberts' 

 method 8 , in which the finely minced pancreas is extracted for five or 



1 Kiihne, Lehrb. d. physiol. Chem. 1868, S. 117. Maly in Hermann's Hdbch. d. 

 Physiol. Bd. v. 2, S. 194. 



2 Musculus und Gruber, Zt. f. physiol. Chem. Bd. n. (1878), S. 177. Musculus 

 und v. Mering, Ibid. S. 403. v. Mering, Ibid. Bd. v. (1881), S. 185. 



3 Brown and Heron, Liebig's Ann. Bd. cxcix. (1879), S. 165. Ibid. Bd. cciv. 

 (1880), S. 228. Proc. Roy. Soc. No. 204 (1880), p. 393. Confirmed also by the 

 author's own experiments. 



4 Pfliiger's Arch. Bd. n. (1869), S. 198. 



5 Hufner, Jn. f. prakt. Chem. N. F. Bd. v. (1872), S. 372. 



6 Virchow's Arch. Bd. xxv. (1862), S. 279. But see Lossnitzer, Diss. Leipzig, 

 1864. 



7 Arch. f. Anat. u. Physiol. Jahrg. 1873, S. 382. 



8 Proc. Roy. Soc. Vol. xxxn. (1881), p. 145. See also Digestion and Diet, 1891, 

 pp. 16, 69. 



