90 DROSERA ROTUNDIFOLIA. [Cuar. VI. 
first set of leaves acted much less quickly and energetically. 
The angles or projections of the fibrous basis of the enamel 
and dentine (except, perhaps, in No. 4, which could not be 
well observed) were not in the least rounded; and Dr. Klein 
remarks that their microscopical structure was not altered. 
But this could not have been expected, as the decalcification 
was not complete in the three specimens which were carefully 
examined. 
Fibrous Basis of Bone.—I at first concluded, as already 
stated, that the secretion could not digest this substance. I 
therefore asked Dr. Burdon Sanderson to try bone, enamel, 
and dentine, in artificial gastric juice, and he found that they 
were after a considerable time completely dissolved. Dr. 
Klein examined some of the small lamelle, into which part of 
the skull of a cat became broken up after about a week’s im- 
mersion in the fluid, and he found that towards the edges the 
“ matrix appeared rarified, thus producing the appearance as 
if the canaliculi of the bone-corpuscles had become larger. 
Otherwise the corpuscles and their canaliculi were very 
distinct.” So that with bone subjected to artificial gastric 
juice complete decalcification precedes the dissolution of the 
fibrous basis. Dr. Burdon Sanderson suggested to me that 
the failure of Drosera to digest the fibrous basis of bone, 
enamel, and dentine, might be due to the acid being con- 
sumed in the decomposition of the earthy salts, so that there 
was none left for the work of digestion. Accordingly, my 
son thoroughly decalcified the bone of a sheep with weak 
hydrochloric acid; and seven minute fragments of the fibrous 
basis were placed on so many leaves, four of the fragments 
being first damped with saliva to aid prompt inflection. All 
seven leaves became inflected, but only very moderately, in 
the course of a day. They quickly began to re-expand; five 
of them on the second day, and the other two on the third 
day. On all seven leaves the fibrous tissue was converted 
into perfectly transparent, viscid, more or less liquefied little 
masses. In the middle, however, of one, my son saw under 
a high power a few corpuscles, with traces of fibrillation in 
the surrounding transparent matter. From these facts it is 
clear that the leaves are very little excited by the fibrous 
basis of bone, but that the secretion easily and quickly 
liquefies it, if thoroughly decalcified. The glands which 
had remained in contact for two or three days with the 
viscid masses were not discoloured, and apparently had 
