IAP. III.] THE DI ASTATIC ENZYME OF THE PANCREAS. 203 



I. THE DI ASTATIC ENZYME. 



The saliva, we have seen, is a liquid which only possesses an 

 amylolytic action in a few animals, the great majority of animals hav- 

 ing a saliva which possesses no diastatic ferment. 



History of Bouchardat and Sandras 1 , in 1845, first discovered 



discovery. anc j established with precision by means of observations 

 carried on with the aid of pancreatic infusions, as well as of small 

 quantities of pancreatic juice obtained from hens and geese, that this 

 secretion possesses powerful diastatic properties, starch being rapidly 

 converted into glucose. They extended their observations to rabbits. 



It has been erroneously stated by many writers possessing high 

 authority that this discovery was first of all made by Professor 

 Valentin of Bern. The statement, so far as the author can make 

 out, first appeared in Frerichs' article 'Verdauung/ in Wagner's 

 Handworterbuch der Physiologic, Vol. ill. part 1, p. 847, and has been 

 repeated by subsequent authors (Bonders, Colin and Maly). Thus 

 Bonders says (Physiologie des Menschen, Vol. I. p. 264), "Valentin 

 scheint zuerst gefunden zu haben, dass der Bauchspeichel die Eigen- 

 schaft besitzt Starkemehl schnell in Zucker umzuwandeln, und alle 

 spateren Untersuchungen haben dies bestatigt." 



The observations of the distinguished Bernese physiologist Valen- 

 tin are recorded in his Lehrbuch der Physiologie (Braunschweig, 

 1844), Vol. I. p. 340 and 341. They were experiments in which a 

 complex mixture of alimentary substances and of digestive juices 

 were observed, and so far from proving the conversion of starch into 

 sugar, scarcely warranted even the modest and cautious conclusion 

 which Valentin expressed as follows : " Wie man sieht, erlauben 

 diese Erfahrungen noch keine irgend bestimmenden Schliisse. 

 Hochstens deuten sie darauf hin, dass vielleicht die Pancreasfliissig- 

 keit die Fahigkeit habe, die Starke loslich zu machen und bisweilen 

 eine Umsetzung derselben einzuleiten." No better example could 

 be given of the way in which errors in scientific history have been 

 propagated by the habit of quoting opinions at second hand without 

 taking the trouble to examine the evidence on which the opinions 

 were based ! 



The action of pancreatic juice on raw starch is generally stated to 

 be but slight 2 ; on starch mucilage it is surprisingly great. At 35 the 

 action is intensely energetic. 



The diastatic action of the diffluent, abnormal, secretion from per- 

 manent fistulse is said (Kuhne) to be as powerful as that of the 

 coherent concentrated liquid of permanent fistulse. 



1 Bouchardat et Sandras, 'Des fonctions du pancreas.' Comptes Rendus, de 

 V Academic des Sciences, Vol. xx. 14 Avril, 1845. 



2 Kiihne is not of this opinion. 'Aus roher Starke, wie aus gekochter bildet 

 ein einziger Tropfen des Secrets mit rapider Geschwindigkeit Zucker.' Lehrbuch. 

 p. 117. 



