90 DROSERA ROTUNDIFOLIA. [Chap VI. 



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. 



Fibroiis 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 lamellae, into which 

 part of the skull of a cat became broken up after about a 

 week's immersion in the fluid, and he found that towards 

 the edges the " matrix appeared rarefied, thus producing the 

 appearance as if the canaliculi of the bone-corpuscles had 

 become larger. Otherwise the corpuscles and their canali- 

 culi were very distinct." So that with bone subjected to 

 artificial gastric juice complete decalcification precedes the 

 dissolution of the fibrous basis. Dr. Burdon Sanderson sug- 

 gested to me that the failure of Drosera to digest the fibrous 

 basis of bone, enamel, and dentine, might be due to the acid 

 being consumed in the decomposition of the earthy salts, so 

 that there was none left for the work of digestion. Accord- 

 ingly, 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 frag- 

 ments being first damped with saliva to aid prompt inflec- 

 tion. All seven leaves became inflected, but only very mod- 

 erately, 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 tis- 

 sue 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 



