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MESSRS. J. TOMES AND C. DE MORGAN ON THE 
nishes with the increasing age of the individual. It may however be observed in the 
bones of those who have passed the sixtieth year. The more recently formed systems 
differ from those of older date in the somewhat larger size of their lacunae and cana- 
liculi, and in the greater abundance of the latter, as shown in fig. 6, Plate ^ I. 
Laminoe of ^owe.— Lamination is a tolerably constant character of mammalian 
bone, although the degree of its distinctness is subject to considerable variation. In 
the bones of young subjects it is less pronounced than in those of mature animals 
(fig. 4, Plate VI.); it is also much less observable in the cancellous than in the com- 
pact tissue. When lamination reaches its highest degree of development, each 
lamina is seen to be made up of two parts, an outer, which is highly granular, com- 
posed oftentimes of a single line of large granules or cells*, as shown in Plate VI. 
fig. 8 ; and an inner portion, which is singularly clear and transparent, and to all 
appearance without granulation or any recognizable structure. 
Kolliker has described and figured a somewhat similar appearance from a specimen 
treated with turpentine, but he does not seem to regard it as very readily discoverable 
in ordinary preparations f-; there is, however, no difficulty in exhibiting this arrange- 
ment of structure in well-made sections, either simply polished or (which is better) 
put up in hard Canada balsam. 
Very favourable views of lamination may be seen in transverse sections from the 
shafts of long bones ; some of the most striking illustrations in the possession of the 
authors were obtained from the tibia of a subject the whole of whose bones were 
slightly hypertrophied, and from the femur of a limb which had from infancy been 
atrophied and useless. 
Strongly marked laminae, with their transparent and granular portions, are how- 
ever not always met with ; yet in their absence the observer will seldom fail to find 
laminae of more uniform granularity surrounding the Haversian canals in well- 
marked concentric rings. 
On examining the Haversian systems, it will be seen that the peripheral lamina 
has its internal surface marked by an even line, while the external is subject to slight 
bulgings, which correspond with and accurately fit into the indentations that form the 
margin of a pre-existing Haversian space (Plate VI. fig. 1). Hence the outer lamina of a 
system will present on its external surface a certain number of alternating dilatations 
and contractions ; a peculiarity possessed by none of the more internal of the series. 
We may, however, find the whole of the laminse of a system presenting different 
degrees of thickness on the opposite sides of a canal, from the latter being a little 
eccentric in its position. But when the eccentricity is considerable, as in the case 
illustrated in Plate VI. fig. 7, the laminae are not all continued round the canal Hence, 
* The nature of these bodies will be more fully considered under the head of development and growth of bone. 
t Kollikee, oper. cit. page 284. In ‘ The Microscopic Anatomy of the Human Body,’ by A. H. Hassall, 
this appearance is indistinctly figured, but no description of it can be found in the letterpress. 
t Kollikee, oper. cit. at page 283, states that in the eccentric systems the whole of the laminse generally 
