108 DROSERA ROTUNDIFOLIA. CHAP. VI 



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 lamellre, 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 rarified, thus producing the appear- 

 ance as if the canaliculi of the bone-corpuscles had 

 become larger. Otherwise the corpuscles and theiv 

 canaliculi were very distinct." So that with bone 

 subjected to artificial gastric juice complete de- 

 calcification 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 consumed in the decomposition of the earthy 

 salts, so that there was none left for the work of 

 digestion. Accordingly, my son thoroughly decal- 

 cified 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. 



