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S. SAAVAMUR A. 



salivary glands ; and that in the middle intestine (now generally 

 called the stomach) the fluid being neutral or alkaline, had 

 the power of decomposing albumen and saponifying fat (with 

 Hydrophilinen and Scarbaeiden diastatic enzyme was also 

 present) ; and finally that in the end-intestine (now generally 

 called the intestine) there existed no digestive ferment. The 

 conclusion obtained by jousset, who studied Blatta orientalis, 

 was nearly the same as that of Plateau, the only difference 

 being that in Blatta orientalis, the fluid in the middle intestine 

 was acid, and contained no diastatic enzyme. 



The investigations made by Krukenberg 1 were much more 

 extensive than those above mentioned, but as unfortunately 

 the author of this paper has had no opportunity of reading his 

 original reports, the details of his investigations can not here be 

 mentioned. The chief points of the summary of his experiments 

 are, however, as follows : — 



I. In Insecta and in other Arthropoda trypsin predominates 

 over pepsin. 



II. The property of the tryptic enzyme of insects is differ- 

 ent from that of Vertebrata, other Arthropoda, and 

 Mollusca. 



III. In Invertebrata there being no division of the intestines 

 which is specialized as stomach, corresponding to the 

 stomach of Vertebrata, a certain part of the intestines 

 is commonly regarded as a stomach. 

 Krukenberg called the tryptic enzyme of insects "Isotrypsin" 

 but in what respect it differs from the known trypsin is not ex- 

 plained. 



Biedermann- studied the digestion of Tenebrio molitor 

 i Coleoptera). and found that the secretion in the upper part of 

 the middle intestine had an acid reaction, while in the lower 

 part it was always alkaline ; and further that it acted upon 

 starch, disaccharides, fat, and albumen, but not upon cellulose ; 

 and finally that the albumen was split up into amido-compounds 

 as in the case of tryptic digestion. Besides these investigations, 

 the discovery of invertin in the head of honey-bees by Erlen- 

 meyer and Planta 3 may be mentioned. 



1 Fortschritte der Tierchemie. iSSo. 



2 Arendt. Chemisches Central-Blatt. 1S9S. 



3 Biedtrmanns Central-Blatt fur Agrikulturchemie. 1879, 



