THE MICROTOMIST'S VADE-MECUM

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CHAPTER      XXXVI.                           btr
RETINA OF VERTEBRATA.                          IfefrS
526. Chromic Acid for Study of Retina (Max Schultze's           0o
method').-For the differentiation of the connective-tissue         h(id
radial-fibres and the nervous radial-fibres, maceration in        ration.
chromic acid of -. per cent.                                      vl1PT
527. Retina (Max Schultze's methods 2).-Osmic acid.-Used        01
in somewhat concentrated solutions (1 to 1 per cent.), it acts
first as a fixing and then as a hardening agent.                  Wours
Strong solutions.-After half an hour's immersion in such       totaliti
a solution small pieces may be teased in a drop of water on       III W6
a slide. It is then easy to split them into radial laminee, in
which the fibres of the rods and cones can be distinguished
(and even isolated if they have not already become too brittle).  1op
If, however, portions of retina be allowed to remain for as        ntrt
much as twenty-four hours in the solution they will not
suffer; they should be washed out in water, in which they        elemen
may remain for days.                                              1 Ri1
The staining action of these solutions is specific as regards
the outer segments of the rods (at least it is so as regards
frogs and fishes; as to mammalia the reaction does not appear     Ct.
to be constant).                                                   ad
(The rods and cones are perfectly preserved in strong solu-
tions and the nerve-fibres are not varicose if the solution be
strong enough.-A. B. L.)
1 'Arch. Mik. Anat.,' i (1866), p. 179.
Ibid., ii (1866), p. 270.

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