Chat. XVI. 



MOVEMENTS OF THE LEAVES. 



373 



apart from one another. After 24 hrs. the margin was greatly 

 and equally incurved (see fig. 16) throughout this space, and for 

 a length of -12 or -13 of an inch (3"048 or 3"302 mm.) above and 

 below each bit; so that the margin had been affected over a 

 greater length between the two bits, owing to their conjoint 

 action, than beyond them. The bits of meat were too large to 

 be clasped by the margin, but they were tilted up, one of them so 

 as to stand almost vertically. After 48 hrs. 

 the margin was almost unfolded, and the 

 bits had sunk down. When again exa- 

 mined after two days, the margin was quite 

 unfolded, with the exception of the natu- 

 rally inflected edge; and one of the bits 

 of meat, the end of which had at first 

 touched the edge, was now '067 of an inch 

 (1*70 mm.) distant from it; so that this 

 bit had been pushed thus far across the 

 blade of the leaf. 



Experiment 7. — A bit of meat was placed 

 close to the incurved edge of a rather young 

 leaf, and after it had re-expanded, the bit 

 was left lying 'll of an inch (2*795 mm.) 

 from the edge. The distance from the edge 

 to the midrib of the fully expanded leaf 

 was "35 of an inch (8'89 mm.); so that the 

 bit had been pushed inwards and across 

 nearly one-third of its semi-diameter. 



Experiment 8. — Cubes of sponge, soaked in a strong infusion 

 of raw meat, were placed in close contact with the incurved 

 edges of two leaves, — an older and younger 'one. The distance 

 from the edges to the midribs was carefully measured. After 



1 hr. 17 m. there appeared to be a trace of incurvation. After 



2 hrs. 17 m. both leaves were plainly inflected; the distance 

 between the edges and midribs being now only half what it was 

 at first. The incurvation increased slightly during the next 

 4:2 hrs., but remained nearly the same for the next 17 hrs. 30 m. 

 In 35 hrs. from the time when the sponges were placed on the 

 leaves, the margins were a little unfolded — to a greater degree 

 in the younger than in the older leaf. The latter was not quite 

 unfolded until the third day, and now both bits of spoDge were 

 left at the distance of "1 of an inch (2-54 mm.) from the edges ; 

 or about a quarter of the distance between the edge and midrib. 

 A third bit of sponge adhered to the edge, and, as the margin 

 unfolded, was dragged backwards, into its original position. 



Fig 16. 

 {Pinguicula vulgaris.) 



Outline of leaf, with 

 right margin inflected 

 against two square bits 

 of meat. 



