Chap. XV. ABSORPTION. 337 



have been slightly acted on and rendered soluble 

 within the above stated short periods. 



The glands have not only the power of rapid absorp- 

 tion, but likewise of secreting again quickly ; and this 

 latter habit has perhaps been gained, inasmuch as 

 insects, if they touch the glands, generally withdraw the 

 drops of secretion, which have to be restored. The exact 

 period of re-secretion was recorded in only a few cases. 

 The glands on which bits of meat were placed, and which 

 were nearly dry after about 1 hr. 30 m., when looked 

 at after 22 additional hours, were found secreting ; so 

 it was after 24 hrs. with one gland on which a bit 

 of albumen had been placed. The three glands to 

 which a minute drojD of a solution of nitrate of 

 ammonia was distributed, and which became dry after 

 2 hrs., were beginning to re-secrete after only 12 addi- 

 tional hours. 



Tentacles Licapahle of Movement. — Many of the tall 

 tentacles, with insects adhering to them, were care- 

 fully observed ; and fragments of insects, bits of raw 

 meat, albumen, &c., drops of a solution of two salts 

 of ammonia and of saliva, were placed on the glands 

 of many tentacles ; but not a trace of movement could 

 ever be detected. I also repeatedly irritated the 

 glands with a needle, and scratched and pricked the 

 blades, but neither the blade nor the tentac'les became 

 at all inflected. We may therefore conclude that 

 they are incapable of movement. 



On. the Poiuer of Absorption i^ossessed hj the Glands. — 

 It has already been indirectly shown that the glands 

 on pedicels absorb animal matter ; and this is further 

 shown by their changed colour, and by the aggregation 

 of their contents, after they have been left in contact 

 with nitrogenous substances or liquids. The following 

 observations apply both to the glands supported on 



