A TECHNIQUE FOR CUTTING SERIAL SECTIONS OF
                         CHITINOUS OBJECTS*

                                             BY

                         S. N. SAPRE, B.Sc., G.B.V.C.

Research Scholar, Imperial Veterinary Research Institute, Mukteswar

                    (Received for publication on 15th June 1939)

                                   (With one text-figure)

THE cutting of serial sections of chitinous objects has been called by
Guyer [1936] the ' microtomist's despair', while Bolles Lee [1928] regards
it as a ' grim business'. Likewise, Eltringham [1930] refers to the ' evil
tendencies' of the chitin which is ' liable to defeat almost every known
method of section-cutting'.

For some time past, the author has been working on the anatomy and
histology of Ornithodorus papillipes Birula (O. crossi Brumpt) and, by the
application of a method which he has developed as a result of extensive ex-
perimentation has succeeded in obtaining satisfactory serial sections of these
ticks without injuring the internal parts.

Fifteen fixatives recommended by various workers were tested in this
connexion and the two main conclusions that emerged out of these tests were
that fluids containing formaldehyde were not suitable for fixing chitinous
objects and that the addition of nitric acid improved the action of the fixa-
tive.

The formula of the fixative used by the author is as follows :

The material is fixed for half to one hour and then placed in ' diaphanol'
(otherwise known as chlorodioxydacetic acid) for softening the chitin further.
The diaphanol is obtainable from firms in England but it can also be prepared
in the laboratory as follows [Schmidt, 1921] :—

Take 4 gm. of powdered crystalline potassium chlorate and 15 gm.
of powdered crystalline oxalic acid in a flask and add 2 c. c. of water.
The flask is now kept in a water bath at 60° C. and the liberated gas (chloro-
dioxyd) is passed through a wash-bottle containing a few c. c. of water and
dissolved in 500 c. c. of water in a brown glass bottle (Fig. 1), which is kept

           * Paper read at the Indian Science Congress held at Lahore, January, 1939.

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