OSSEOUS TISSUE. 
lation, even though the contents of the cells 
remain unaltered, which is not probable. 
Cells of smaller form and having branching 
tubes are to be found in the vegetable world. 
The shells of various fruits, as the cocoa-nut, 
peach, common nut, &c. present cells so like 
those of bone that a section of shell has often 
been mistaken for one of bone. In this instance 
they also answer the purposes of circulation. . 
Lhe growth of bones.—Many experiments 
have been made to ascertain the mode of 
growth in bones, but they have given as their 
results the direction of increase rather than the 
process of interstitial growth. The experiments 
alluded to are commonly spoken of as the 
madder experiments, and were instituted by 
Du Hamel, Detlif, Hunter, Stanley, Paget, 
and others. 
It was discovered that phosphate of lime 
acts upon the colouring matter of madder as a 
mordant. Thus, if phosphate of lime be pre- 
cipitated from a state of chemical combination 
in a solution of madder, the colouring matter 
of the madder is carried down with the phos- 
phate in a state of chemical combination, im- 
parting to the phosphate a red colour, which is 
not diminished by repeated washing, but gra- 
dually fades by exposure to light. But, before 
this discovery was made, it was found that the 
bones of some pigs that had been accidentally 
fed upon madder were rendered red. Atten- 
tion having been drawn to this curious fact that 
madder given in the food reddens the bones 
of the animal, the madder experiments were 
undertaken, and !ed to the following results. 
If madder be given to a growing animal, 
and the bones be examined by making a sec- 
tion of a cylindrical bone, a ring of reddened 
bone will be seen to form the circumference of 
‘the bone, and a similar reddened ring to form 
the parietes of the medullary cavity. If in this 
‘experiment the animal had been old, these 
rings of red would not have been seen, or, if 
‘Seen, only very faintly. From these two ex- 
periments it has been deduced that the bone, 
or rather the phosphate of lime, which has 
been deposited during the exhibition of the 
-madder, has alone been reddened. 
_ ff, however, after giving madder to a grow- 
ing animal for a time, its use be discontinued 
for awhile and then be again given, several 
Tings of reddened bone will be observed on 
Making a section of a cylindrical bone, that is, 
reddened bone will be deposited during the use 
of the madder, and white bone at the interval 
f its discontinuance. So that, by the alter- 
mate use and disuse of madder, rings of red 
and of white bone will be formed to a consi- 
erable number. From these experiments it 
has been deduced that bones increase in their 
jameter by the development of the bone on 
surface somewhat in the same manner that 
crystal increases in size by additions to its 
ce. 
_Mr. Gibson, however, for a while threw some 
bts on the value of the madder experiments 
the deductions from them, by stating that 
serum of the blood had an affinity for the 
853 
colouring matter of madder superior to that of 
the phosphate of lime, and that the bone became 
stained only after the serum had been tho- 
roughly saturated with madder, and more, that 
the serum, from the discontinuance of madder 
in the food, or losing the colouring matter, 
absorbed that existing in the bones. 
Mr. Paget has, however, proved that the 
affinity is far stronger between phosphate of 
lime and the colouring matter of madder than 
between serum and the latter. These experi- 
ments seem at first sight far more valuable than 
a closer investigation will prove them to be, as 
will be seen on considering the following fact, 
namely, that not only is the surface of the bone 
with the walls of the medullary cavity tinged red 
by the exhibition of madder, but also the cir- 
cumference of every Haversian canal through- 
out the bone, in fact every surface that lies in 
contact with a vessel or vessels. The fact that 
every Haversian canal has its coloured ring had 
escaped observation, as these experimenters 
had been limited to the use of the naked eye, 
whereas the Haversian canals, with their co- 
loured rings, are only seen by the use of the 
microscope. 
It therefore remains for observation to be 
made upon the effects of consecutive feeding 
with and without madder, upon the Haversian 
canals, before any very accurate deductions 
can be made. 
Other experiments have been tried in inves- 
tigating the growth of bones. 
Rings of metal have been lightly fixed round 
a long bone, which after a while has been found 
to contain the rings in its medullary cavity, 
from which it has been inferred that the bone 
has grown by additions to its circumference, 
while the medullary cavity has been enlarged by 
the absorption of the bone forming its parietes. 
These experiments, which were made by Du 
Hamel, have been confirmed by Hunter and 
Stanley. 
Experiments of a similar nature have been 
made to determine the manner of growth in 
the length of bones. Thus holes have been 
bored in the tibia of a dog at definite intervals, 
which intervals, after the lapse of some days, 
have been found altered in the relative lengths. 
The intervals near the ends of the bone have in- 
creased considerably, while those situated near 
the centre of the bone have scarcely changed. 
Mr. Stanley has shown that in some animals 
the growth is greatest at the distal end, while in 
other animals it is greater toward the proximal 
end of a long bone. ; ; 
In the two experiments which I have related 
in a previous part of this article the walls of the 
medullary cavity were as distinctly reddened as 
the circumference of the bone, and the cir- 
cumference of each Haversian canal as either. 
These would therefore prove too much for the 
theory which supposes that a long bone in- 
creases its diameter by the depositions upon its 
surface and under its medullary cavity by the 
absorption of the walls. Supposing the idea 
that phosphate of lime, which is deposited 
during the exhibition of madder, is alone red- 
