ALIMENTARY CANAL IN THE BEE 527 



Lactase. 

 Lactase is a ferment splitting the disaccharid — milk sugar — 

 into monosaccharids — glucose and galactose. There are no 

 data in literature concerning the production of lactase in the 

 intestine of the bee. In our experiments the presence of lactase 

 was not established. 



Invertase. 



The presence of invertase in the organism of the bee was 

 first discovered by Erlenmeyer and Planta in glycerine extracts 

 from the heads, thoraces, and abdomens of bees. The extracts 

 from the heads and abdomens prove to be more active than 

 those from the thoraces. 



Axenfeld divided the intestine of the bee into three parts — 

 crop, stomach, and hind-gut. On acting with the named 

 portion of the intestine on the solution of saccharase, the greatest 

 activity was exhibited by the stomach, whereas the crop and 

 hind-gut inverted sugar very weakly. The author named 

 supposes that invertase is produced only by the stomach, 

 but a small quantity of it is transferred mechanically to the 

 hind-gut. 



Li our experiments we added to 5 c.c. of 10 per cent, solution 

 of cane-sugar the tested extracts from the intestine of the 

 bee and drone in quantities shown in the table, the liquid 

 being placed — after addition of 1 c.c. of toluol as a conserving 

 medium — in the thermostat at 3G-40'' C. for twenty-four to 

 forty-eight hours ; then after cooling the liquid to the tempera- 

 ture of the room and adding 1 drop of ammonia, in order to 

 avoid birotation, the rotation of the plane of polarization was 

 determined in a tube of 200 mm. 



The results obtained are adduced in Table IV. 



On examining the data adduced in the table it is seen that 

 in regard to invertase the first two experiments differ essen- 

 tially from the remaining, notwithstanding the similar methods 

 employed in the analysis. Whereas in all the experiments, 

 except the first two, the extracts from the stomach show an 

 essential decrease of the right rotation of the polarization plane, 



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