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PROGRESS OF MICROSCOPICAL SCIENCE. 
Structure of Connective Tissue and Tendon . — A paper contained in 
M. Brown- Sequard’s ‘Archives de Physiologie ’ for 1869, by M. Ranvier, 
lias proved to be tbe starting-point for a new series of researches on 
the structure of connective tissue and tendons, wbicli has recently 
been taken up by M. Boll and Dr. Mitchell Bruce, and which has led 
to a description of this tissue materially diiferent from that contained in 
the text-books of some twenty years ago, as well as from the more modern 
doctrines of Virchow. The latter observer maintained that connective 
tissue was originally composed of cells, the walls of which became 
thickened and condensed, forming the intercellular substance, and 
ultimately underwent fibrillation. The central portion both of the 
cells and of the processes given off from them he believed remained 
hollow, and by their intercommunication constituted a canalicular 
system, ministering to the nutrition of the tissue. The researches of 
Recklinghausen on the cornea to some extent effected a modification 
of Virchow’s views, by showing that the true cells of that membrane 
did not form, but were contained within, the stellate cavities and 
spaces, through which they moved by virtue of their amoeboid activity. 
The researches of Kiihno on the intermuscular connective tissue of 
the frog showed that in this animal the cells of that tissue are destitute 
of a cell wall, and are not contained in canals, but wander freely 
through the meshes of the connective tissue. It followed that, in the 
frog at least, the general idea of a plasmatic system, afforded by the 
study of the cornea after impregnation with nitrate of silver, could 
not be extended to the connective tissue generally. Ranvier com- 
menced by examining the tendons in the tail of young rats, which, 
after removal from the body, were stretched on the slide, kept in position 
by a drop of sealing-wax, stained with carmine, and acted on with 
dilute acetic acid. On examination with a magnifying power of 100 
diameters, the tissue was found to present parallel continuous red 
strife, which, under higher powers, proved to be cylindrical tubes ; and 
these were seen to be crossed by transverse lines, dividing them into 
nearly equal segments. On slight pressure being exercised, each of 
these little segments or cylinders split longitudinally, and unrolling 
itself, proved to be a square cell-plate or lamina, with a nucleus near 
its centre. Around the cell tubes is an elastic tube or sheath. The 
tendons are thus, according to Ranvier, permeated by a system of 
parallel tubes, the walls of which aro composed of square cells rolled 
round till their edges meet, and placed end to end. The stellate 
figures insisted on so strongly by Virchow as representing corpuscles, 
he regards as being merely sections of the superficial layer of con- 
nective tissue investing the several fasciculi of the tendon, and in 
these septa his cellular tubes run. The stellate figures brought into 
view by staining in the subcutaneous connective tissue he also regards 
as purely illusory ; and endeavours to prove it by producing artificial 
oedema with injection of various fluids into the living animal, and 
