Chap. XVI. SECRETION, ABSOEPTION, DIGESTION. 383 



of a leaf ; in 6 hrs. there was much secretion, which after 48 hrs. 

 accumulated in a little pool round the cube near the margin. 

 This cube was much more dissolved than that on the blade of 

 the leaf ; so that after three days it was greatly reduced in size, 

 with all the angles rounded, but it was too large to be wholly 

 dissolved. The secretion was partially absorbed after four days. 

 The cube on the blade was much less reduced, and the glands 

 on which it rested began to dry after only two days. 



(7) Fibrin excites less secretion than does meat or albumen. 

 Several trials were made, but I will give only three of them. 

 Two minute shreds were placed on some glands, and in 3 hrs. 

 45 m. their secretion was plainly increased. The smaller shred 

 of the two was completely liquefied in 6 hrs. 15 m., and the other 

 in 24 hrs. ; but even after 48 hrs. a few granules of fibrin could 

 still be seen through a lens floating in both drops of secretion. 

 After 56 hrs. 30 m. these granules were completely dissolved. 

 A third shred was placed in a little pool of secretion, within 

 the margin of a leaf where a seed had been lying, and this 

 was completely dissolved in the course of 15 hrs. 30 m. 



(8) Five very small bits of gluten were placed on a leaf, and 

 they excited so much secretion that one of the bits glided 

 down into the marginal furrow. After a day all five bits seemed 

 much reduced in size, but none were wholly dissolved. On the 

 third day I pushed two of them, which had begun to dry, on 

 to fresh glands. On the fourth day undissolved traces of three 

 out of the five bits could still be detected, the other two having 

 quite disappeared ; but I am doubtful whether they had really 

 been completely dissolved. Two fresh bits were now placed, 

 one near the middle and the other near the margin of another 

 leaf; both excited an extraordinary amount of secretion; that 

 near the margin had a little pool formed round it, and was 

 much more reduced in size than that on the blade, but after 

 four days was not completely dissolved. Gluten, therefore, 

 excites the glands greatly, but is dissolved with much diificulty, 

 exactly as in the case of Drosera. I regret that I did not try 

 this substance after having been immersed in weak hydrochloric 

 acid, as it v/ould then probably have been quickly dissolved. 



(9) A small square thin piece of pure gelatine, moistened 

 with water, was placed on a leaf, and excited very little secre- 

 tion in 5 hrs. 30 m., but later in the day a greater amount. 

 After 24 hrs. the whole square was completely liquefied; and 

 this would not have occurred had it been left in water. The 

 liquid was acid. 



(10; Small particles of chemically prepared casein excited 



