lyi 



BOTANICAL GAZETTE. 



Experiment No. 8. —Placed a cube (edge ii6inch) of hardened 

 egg albumen upon the disk of a leaf, at 2.45 p. m., June 10, 

 1879. . 

 30 min. perhaps there had been a slight movement of the disk ten- 

 tacles, but none of the others showed any change, 

 evident movement of the disk tentacles, 

 the edge of the leaf and all of the disk, submarginal and 

 marginal tentacles were inflected and touched the speci- 

 men, except the tentacles and edge of the leaf on one side 

 for about one fourth of the circumference, 

 all the tentacles except five or six of the marginal, and the 

 entire edge of the blade, were inflected*; egg all softened, 

 opaque but not viscid, 

 entirely closed except two of the marginal tentacles. 

 47 hrs. several of the marginal tentacles were reflexed; a soft and 



viscid semi-fluid substance is all that remains of the egg. 

 67 hrs. the marginal tentacles, with the exception of two or three, 

 were standing at an angle of 90° with the blade, the sub- 



2 hrs. 

 17 •' 



24 



41 



*The margin of the blade of the leaf is often more or less incurved, accord, 

 ing to the substance undergoing absorption ; apparently if the matter is easily 

 absorbed the whole leaf seems to be excited and all parts are l)rought into 

 action. In this case, however, the method of incurving was somewhat pecu- 

 liar, and I am not aware that it has ever been recorded. When fnlly inflected 

 the blade was pentagcmal in outline. (Fig. 1.) 



To the intense exertion on the part of the 

 leaf to assimilate all the absorbable matter 

 contained in the substance placed upon the 

 disk; to the undue excitement caused by an 

 over-dose of an easily absorbed food, I am led 

 to ascribe, as tiie direct cause, the death of the 

 leaf, noted at tiie end of the experiment. 



Three other forms of marginal incurvation 

 are mentioned by Darwin. [Insectivorous 

 Plants, p. 12.] 



"For instance, I placed bits of hard-boil- 

 ed egg on three leaves ; one had the apex bent 

 towards the base; the second had both distal 

 margins much incurved, so that it became al- 

 most triangular in outline, and this jxTJiapsis 

 the conuiionest case; while the third blade 

 was not at all affected, though the tentacles 

 wei'c as closely intlected as in the two previous cases. The whole blade also 

 generally rises or bends upwards, -tuid thus forms a smaller angle with the foot- 

 stalk than it did before. This appears at fir.st sight a distinct kind of move- 

 ment, but it results from the incurvation of that part of tlie margin which is 

 attached to the foot-stalk, causing the blade, as a whole, to curve or move up- 

 wards." 



Fig. 1. (:1X) 



