88 DROSERA ROTUNDIFOLIA. (Cuap. VI. 
Bone.—Small smooth bits of the dried hyoidal bone of a 
fowl moistened with saliva were placed on two leaves, and a 
similarly moistened splinter of an extremely hard, broiled 
mutton-chop bone on a third leaf. These leaves soon became 
strongly inflected, and remained so for an unusual length of 
time ; namely, one leaf for ten and the other two for nine 
days. The bits of bone were surrounded all the time by acid 
secretion. When examined under a weak power, they were 
found quite softened, so that they were readily penetrated by 
a blunt needle, torn into fibres, or compressed. Dr. Klein 
was so kind as to make sections of both bones and examine 
them.. He informs me that both presented the normal 
appearance of decalcified bone, with traces of the earthy 
salts occasionally left. The corpuscles with their processes 
were very distinct in most parts; but in some parts, 
especially near the periphery of the hyoidal bone, none could 
be seen. Other parts again appeared amorphous, with even 
the longitudinal striation of bone not distinguishable. This. 
amorphous structure, as Dr. Klein thinks, may be the result 
either of the incipient digestion of the fibrous basis or of all 
the earthy matter having been removed, the corpuscles being 
thus rendered invisible. A hard, brittle, yellowish substance 
oceupied the position of the medulla in the fragments of the 
hyoidal bone. 
As the angles and little projections of the fibrous basis 
were not in the least rounded or corroded, two of the bits 
were placed on fresh leaves. These by the next morning 
were closely inflected, and remained so,—the one for six and. 
the other for seven days,—therefore for not so long a time as 
on the first occasion, but for a much longer time than ever 
occurs with leaves inflected over inorganic or even over many 
organic bodies. The secretion during the whole time 
coloured litmus paper of a bright red; but this may have 
been due to the presence of the acid superphosphate of lime. 
When the leaves re-expanded, the angles and projections of 
the fibrous basis were as sharp as ever. I therefore con- 
cluded, falsely, as we shall presently see, that the secretion 
cannot touch the fibrous basis of bone. The more probable: 
explanation is that the acid was all consumed in decomposing 
the phosphate of lime which still remained ; so that none was 
left in a free state to act in conjunction with the ferment 
on the fibrous basis. 
Enamel and Dentine.—As the secretion decalcified ordinary 
