OSSEOUS TISSUE. 
fused state of the specimen, a little dilute 
muriatic acid should be placed upon the glass 
in contact with the specimen. Solution of the 
powdered mass will instantly commence, but 
the broken granules will have disappeared be- 
fore the entire ones are appreciably affected. If 
at this point of the experiment the acid be re- 
moved and replaced by pure water, a perfect 
specimen will be gained. In examining the 
tissue under consideration it is most satisfactory 
to watch the action of the acid upon the cal- 
cined or steamed bone, and especially its action 
upon the small masses, for in these, when un- 
dergoing the action of dilute acid, the granules 
composing them become particularly distinct, 
so that their individual character may be stu- 
’ died ; and if the solvent be not removed, their 
Separate disappearance may be watched as the 
superficial ones are exposed and acted upon by 
the solvent fluid. Ifthe acid be left with the 
so treated bone for a sufficient length of time, 
all the earthy matter will be dissolved and there 
will remain a transparent indistinctly cellular 
mass, which may be supposed to be an inter- 
granular substance, the purpose of which was 
_ to unite the granules into a compact whole. 
Bone which has been treated with dilute 
acid without the previous removal of the ani- 
mal matter, soon loses the earthy component, 
leaving only the animal. This, however, does 
not tend to develope the granularity; indeed 
_ it seems, in most cases, to render it less dis- 
_ tinct than in either the unaltered or the calcined 
bone. The granules themselves are subject to 
some variety in size, commonly varying from 
the one-sixth to one-third the size of a human 
blood globule. 
Of the lamine—The form taken by the 
bone substance is that of lamine, and these 
_ Jaminz have a definite arrangement, so much 
_ so that three distinct systems may be recognised, 
' namely, lamine of the Haversian canals; 
_ secondly, the lamine which connect the 
' Haversian systems; and thirdly, the lamine 
_ which form the surface of the bone and enclose 
_ the two previous orders, 
The lamine of the Haversian canals have a 
concentric arrangement, and present, when 
_ divided transversely, a series of more or less 
aim and perfect rings : see figs. 448 and 450. 
ey are subject to considerable variety in 
_ number, but the more common amount is ten or 
' twelve. Of these, the internal lamina, that which 
forms the parietes of the Haversian canal,is most 
distinctly marked, while each succeeding one as 
‘ou proceed outwards becomes less distinct. The 
ncentric lamine with bone cells and central 
nal have received the name of Haversian 
stem from Dr. Todd and Mr. Bowman in 
eir work on Physiology. 
Connecting these Haversian systems is a 
nd series of lamine, without which the 
former would exist but as a bundle of loose 
tubes. (See fig. 448, c). 
In this substance we find the laminated 
‘arrangement less distinct, far less regular, and 
the lamine individually subject to great 
larity of thickness. “It is often also more 
‘fansparent than either the Haversian or exter- 
VOL. III. 
849 
nal system. Bone cells contained in it are 
also more irregular in shape than those found 
in other situations. The last division consists 
of those lamin which surround the exterior of 
thes bone. These have greater individual 
extent, but are the least numerous. They are 
continuous with the lamine of the Haversian 
system whenever the latter arrive at the surface 
of the bone; the external lamine in this case 
being continuous with the inner laminz of the 
Haversian system. 
Some authors have doubted the existence of 
a laminated arrangement in bone. If, however, 
young bone be examined, all doubt upon the 
subject will be dispelled, and especially if it 
be first macerated in weak muriatic acid, when 
the appearance represented in fig. 450 will be 
seen. In bone so treated the lamin may with 
Fig. 450. 
The lamine as they appear after the removal of the 
animal matter by the action of acid. 
the assistance of two needles be separated. In 
the bones of old animals the lamine are much 
less distinct ; in these, however, they may be de- 
monstrated if acid be used. Though the external 
lamina is very distinct, and therefore the boun- 
dary of each Haversian system, yet in bone of 
advanced age the distinctness is lost in com- 
mon with the definite outlines of the three 
orders of lamine. The cancelli of the can- 
cellous portion of bones are but enlarged 
Haversian canals, which in addition to vessels 
contain fat; the lamine therefore which form 
the walls are those of the Haversian system. 
In connection with this division of the sub- 
ject, the effect of madder. given to an animal 
with its food upon the osseous system may be 
noticed, since the colour is imparted to the 
lamine. By the taking of madder into the 
stomach the effect of giving a deep red tinge is 
very soon observable. Ina pigeon the bones 
were rendered brilliantly red in twenty-four 
hours. In a young pig a similar effect was 
produced in three weeks. 
On making sections of bone so affected the 
colour is found to be present in the external 
laminz of the bone, and in the inner lamine of 
the Haversian system, thereby proving that the 
action of colouring takes place upon those sur- 
faces which lie in contact with vessels. This 
fact, with many others in this article, was men- 
tioned in a paper by the author read before 
the Royal Society in June of 1838. 
Of the Haversian sassateain canals 
I 
