PROGRESS OF MICROSCOPICAL SCIENCE. 
147 
a small smooth-contoured elongated mass of protoplasma is continuous 
at both ends with a fine long thread-like fibre ; in another an 
irregularly contoured, but generally somewhat elongated, mass gives 
off numerous sharply defined, very fine glistening fibres in all direc- 
tions. Sometimes a protoplasmic centre terminates at one end by a 
single fibre, and by two at the other. These fibres are often of great 
length, and the protoplasmic mass can sometimes only be found by 
carefully tracing them whilst moving the object-glass. 
8. Fibrillary tissue is seen to be composed of uniform flat ribbon- 
like bands, whose breadth approaches the diameter of a human red 
blood-corpuscle. These are seen in their simplest form when ex- 
truded from the neurilemma of the sciatic nerve of the frog, which 
takes place within twenty-four hours' maceration. From their posi- 
tion in this membrane they form part of the transparent medium 
which exists between the two layers of quadrangular cells. They 
are mostly marked by a puckered appearance transversely. 
In skin and tendon, after a few days' maceration in the sealed 
fluid, the fibrillary tissue is seen to be composed of extremely fine 
but sharply contoured fibrillaB, arranged in parallel bands, which are 
of the same breadth as the soft ribbon-like bands which are isolable 
from the neurilemma. 
The respective appearances in the neurilemma and in tendon 
indicate extremes in the condition of this tissue, and represent, 
according to the author, primary bundles of connective tissue. 
9. The primary bundles of the cornea are seen only exceptionally 
by this method, but can be demonstrated with great precision by 
sealing up a frog's cornea in a mixture of equal parts of half per cent, 
solution of chloride of gold and concentrated acetic acid. 
10. In nerve-bundles, after twenty-four hours' maceration in 
aqueous humour, some of the medullated fibres may be seen to have 
their contour broken transversely by straight hyaline spaces. The 
author assigns this appearance to the peculiarity of structure described 
by Ranvier. 
11. The breadth and appearance of the rods of the frog's retina 
are nearly identical with those of the primary bundles of neurilemma,. 
The transverse markings described by Max Schultze as being 
produced by the action of osmic acid on the rods and cones, resemble 
the transverse puckerings in the primary bundles. In both rods and 
primary bundles, after prolonged maceration in aqueous humour, the 
free ends of each individual element bend in one direction until they 
join, and the substance of the ring thus formed undergoes in both 
a similar and peculiar process of disintegration. From these facts 
the author infers that the rods and cones of the retina are composed 
of fibrillary tissue in its simplest form. 
12. Transverse sections of muscular fibre, when examined at 
intervals, show varying appearances, only a small minority of such 
preparations being successful. Successful preparations show one or 
more of three appearances ; (a) primary bundles, corresponding to 
Cohnheim's fields; (b) groups of these (secondary bundles), the 
aggregate of which fill up the space bounded by the sarcolemma ; 
