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cartilage cells, and thinks the appearance of spaces is produced 
by the fact that the cartilage substance in the neighbourhood 
of the cells has a refractive index equal to that of watery 
fluids, and thus contrasts with the surrounding more highly 
refractive substance, and especially with the capsular layer. 
Between the cell and the wall of tne cavity there is accordingly 
not a space filled with fluid, but a solid substance continuous 
with the rest of the solid cartilage, but differing from it in its 
optical properties. ‘To this he gives the name of pericellular 
substance. The shrinking of cartilage cells (in various re- 
agents) depends on the swelling up of this substance, which 
thus compresses the cell. Neumann points out that cartilage 
cells, in their sections, do not shift their position or shape with 
slight movements of the object-glass or cover, as must be the 
case if they were free in a cavity; and that when the cells 
fall out, the space left behind is seen to be lined with a pale 
hyaline zone, which becomes especially prominent after the 
application of carmine or iodine. 
The true fundamental substance of the cartilage, which is, 
if these views be correct, everywhere in close contact with 
the cartilage cell, is then differentiated into three modifi- 
cations—the pericellular substance; the capsular substance 
(or so-called wall of the cartilaginous space); and the true 
intercellular substance ; of which the first may become trans- 
formed into the second and the second into the third. Whether 
the pericellular substance is a secretion of the cell, or (accord- 
ing to the views of Schultze and Beale) a transformation of 
part of the cell substance, Neumann cannot decide. He 
further draws attention to the action of iodine on cartilage 
cells, in producing a brownish-red or black-brown colour like 
its reaction with “amyloid” substance, but which is not 
further charged by sulphuric acid. 
In his remarks on the ossification of hyaline cartilage, 
Neumann omits the consideration of the actual deposit of 
lime, so often and minutely described, but devotes himself to 
the question of the formation of the original “ medullary 
spaces,” or cavities of the medullary tissue. According to 
the views of H. Miller, these were formed by the opening 
into one another of a number of cartilage spaces arranged in 
a row or column; an explanation which, if the cartilage 
spaces do not exist, of course becomes untenable. According 
to Neumann, the cartilage cells become arranged, as has often 
been described, in rows or columns, and the remaining true 
intercellular substance, with part of the capsular layer between 
these rows, forms the longitudinal trabecule of bone; while 
the transverse septa connecting these are formed entirely of 
