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, [page 106] as Dr. Klein
thinks, may be the result either of the incipient digestion of the
fibrous basis or of all the animal matter having been removed, the
corpuscles being thus rendered invisible. A hard, brittle, yellowish
substance occupied 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 super-phosphate of lime. When the leaves re-expanded, the
angles and projections of the fibrous basis were as sharp as ever. I
therefore concluded, 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 bone, I
93