CHAP. VII. PHOSPHATE OF AMMONIA. 155 



with the point of a needle on the secretion surrounding several 

 glands. These poured forth much secretion, were blackened, 

 and ultimately died; but the tentacles moved only slightly. 

 The dose, small as it was, evidently was too great, and the 

 result was the same as with particles of the carbonate of 

 ammonia. 



Half-minims of a sohition of one part to 437 of water were 

 placed on the discs of three leaves and acted most energetically, 

 causing the tentacles of one to be inflected in 15 m., and 

 the blades of all three to be much curved inwards in 2 hrs. 

 15 m. Similar drops of a solution of one part to 1312 of water, 

 (1 gr. to 3 oz.) were then placed on the discs of five leaves, 

 so that each received the ^Vo f a grain ('0225 rag.). After 

 8 hrs. the tentacles of four of them were considerably inflected, 

 and after 24 hrs. the blades of three. After 48 hrs. all five 

 were almost fully re-expanded. I may mention with respect 

 to one of these leaves, that a drop of water had been left 

 during the previous 24 hrs. on its disc, but produced no effect ; 

 and that this was hardly dry when the solution was added. 



Similar drops of a solution of one part to 1750 of water (1 gr. 

 to 4 oz.) were next placed on the discs of six leaves ; so that 

 each received g-gVo f a grain ('0169 mg.) ; after 8 hrs. three of 

 them had many tentacles and their blades inflected ; two others 

 had only a few tentacles slightly inflected, and the sixth was 

 not at all affected. After 24 hrs. most of the leaves had a few 

 more tentacles inflected, but one had begun to re-expand. We 

 thus see that with the more sensitive leaves the g-gVo f a grain, 

 absorbed by the central glands, is enough to make many of the 

 exterior tentacles and the blades bend, whereas the j-gVo f a 

 grain of the carbonate similarly given produced no effect ; and 

 ^Vo of a grain of the nitrate was only just sufficient to produce 

 a well-marked effect. 



A minute drop, about equal to -^ of a minim, of a solution of 

 one part of the phosphate to 875 of water, was applied to the 

 secretion on three glands, each of which thus received onlj 

 57 1 00 of a grain ('00112 mg.), and all three tentacles became 

 inflected. Similar drops of a solution of one part to 1312 of 

 water (1 gr. to 3 oz.) were now tried on three leaves; a drop 

 being applied to four glands on the same leaf. On the first 

 leaf, three of the tentacles became slightly inflected in 6 m., and 

 re-expanded after 8 hrs. 45 m. On the second, two tentacles 

 became sub-inflected in 12 m. And on the third all four ten- 

 tacles were decidedly inflected in 12 m. ; they remained so for 

 8 hrs. 30 m., but by the next morning were fully re-expanded. 



