Cuar. VILJ DIGESTION. 91 
absorbed little of the liquefied tissue, or had been little 
affected by it. 
Phosphate of Lime.—As we have seen that the tentacles of 
the first set of leaves remained clasped for nine or ten days 
over minute fragments of bone, and the tentacles of the 
second set for six or seven days over the same fragments, I 
was led to suppose that it was the phosphate of lime, and 
not any included animal matter, which caused such long- 
continued inflection. It is at least certain from what has 
just been shown that this cannot have been due to the 
presence of the fibrous basis. With enamel and dentine (the 
former of which contains only 4 per cent. of organic matter) 
the tentacles of two successive sets of leaves remained inflected 
altogether for eleven days. In order to test my belief in the 
potency of phosphate of lime, I procured some from Prof. 
Frankland absolutely free of animal matter and of any 
acid. A small quantity moistened with water was placed on 
the discs of two leaves. One of these was only slightly 
affected ; the other remained closely inflected for ten days, 
when a few of the tentacles began to re-expand, the rest 
being much injured or killed. I repeated the experiment, 
but moistened the phosphate with saliva to insure prompt 
inflection ; one leaf remained inflected for six days (the little 
saliva used would not have acted for nearly so long a time) 
and then died; the other leaf tried to re-expand on the sixth 
day, but after nine days failed to do so, and likewise died. 
Although the quantity of phosphate given to the above four 
leaves was extremely small, much was left in every case 
undissolved. A larger quantity wetted with water was next 
placed on the disc of three leaves; and these became most 
strongly inflected in the course of 24 hrs. They never re- 
expanded ; on the fourth day they looked sickly, and on the 
sixth were almost dead. Large drops of not very viscid fluid 
hung from their edges during the six days. This fluid was 
tested each day with litmus paper, but never coloured it; 
and this circumstance I do not understand, as the super- 
phosphate of lime is acid. I suppose that some superphos- 
phate must have been formed by the acid of the secre- 
tion-acting on the phosphate, but that it was all absorbed 
and injured the leaves; the large drops which hung from 
their edges being an abnormal and dropsical secretion. 
Anyhow, it is manifest that the phosphate of lime is a most 
powerful stimulant. Even small doses are more or less 
