58 DEOSERA ROTUNDIFOLI4. [( UAP. IV. 



nearly as possible at the same temperature; but I will here and 

 elsewhere give only a few of the many trials made. A leaf was 

 left for 10 m. in water at 100 (37.7 Cent.), but no inflection oc- 

 curred. A second leaf, however, treated in the same manner, had 

 a few of its e.xterior tentacles very slightly inflected in G m., anl 

 several irregularly but not closely inflected in 10 m. A third leaf, 

 kept in water at 105" to 106 (40.5 to 40.l Cent.), was very 

 moderately inflected in -C m. A fourth leaf, in water at 110 

 (43.3 Cent.), was somewhat inflected in 4 m., and considerably so 

 in from 6 m. to 7 m. 



Three leaves were placed in water which was heated rather 

 quickly, and by the time the temperature rose to 115 116 

 (46.l to 46.06 Cent.), all three were inflected. I then removed 

 the lamp, and in a few minutes every single tentacle was closely 

 inflected. The protoplasm within the cells was not killed, for it 

 was seen to be in distinct movement; and the leaves, having been 

 left in cold water for 20 hrs., re-expanded. Another leaf was im- 

 mersed in water at 100 (37.7 Cent.), which was raised to 120 

 (48.8 Cent.) ; and all the tentacles, except the extreme marginal 

 ones, soon become closely inflected. The leaf was now placed in 

 cold water, and in 7 hrs. 30 m. it had partly, and in 10 hrs. fully, 

 re-expanded. On the following morning it was immersed in a weak 

 solution of carbonate of ammonia, and the glands quickly became 

 black, with strongly marke<l aggregation in the tentacles, showing 

 that the protoplasm was alive, and that the glands had not lost 

 their power of absorption. Another leaf was placed in water at 110 

 (43.3 Cent.) which was raised to 120 (48.8 Cent.) ; and every 

 tentacle, excepting one, was quickly and closely inflected. This leaf 

 was now immersed in a few drops of a strong solution of carbonate 

 of ammonia (one part to 109 of water) ; in 10 m. all the glands be- 

 came intensely black, and in 2 hrs. the protoplasm in the cells of the 

 pedicels was well aggregate<l. Another leaf was suddenly plunged, 

 and as usual waved about, in water at 120, and the tentacles be- 

 came inflected in from 2 m. to 3 m., but only so as to stand at right 

 angles to the disc. The leaf was now placed in the same solution 

 (viz. one part of carbonate of ammonia to 109 of water, or 4 grs. to 

 1 oz., which I will for the future designate as the strong solution), 

 and when I looked at it again after the interval of an hour, the 

 glands were blackened, and there was well-marked aggregation. 

 After an additional interval of 4 hrs, the tentacles had become much 

 more inflected. It deserves notice that a solution as strong as this 

 never causes inflection in ordinary cases. Lastly, a leaf was sudden- 

 ly placed in water at 125 (51.0 Cent.), and was left in it until the 

 water coole<l ; the tentacles were rendennl of a bright red and soon 

 became inflected. The contents of the ceils underwent some degree 

 of aggregation, which in the course of three hours increased ; but the 

 masses of protoplasm did not become spherical, as almost always 

 occurs with leaves immersed in a solution of carbonate of ammonia. 



We leam from these cases that a temperature of from 

 120 to 125* (48**.8 to 51*.6 Cent.) excites the tentacles 



