A modified Gold Chloride method for the
demonstration of Nerve Endings.
By
Fred W. Gairns,
Institute of Physiology, University of Glasgow.
With Plates 7 and 8.
DUEING a series of histological investigations into the nervesupply of certain skeletal muscles, which have from time to
time been undertaken in this laboratory, great difficulty has
been found in obtaining constant and satisfactory results.
The experience of this laboratory has been that, on the whole,
the gold chloride methods give the greatest promise of reliability, and an attempt has been made to determine, so far as
possible, the conditions necessary for a technique which will
give uniformly good results. Many modifications of the existing
techniques were tried with little success.
Eventually, it was found that the method described below
yielded results both constant and satisfactory.
MATEEIAL REQUIRED.
Fresh lemon juice (filtered), 1 per cent, gold chloride (British),
formic acid 1*22 s.g., pure glycerine, distilled water, bone or
wax-tipped forceps, clean cloth, and some small bottles.
All solutions must be made up in distilled water, and only
small quantities of the various solutions (except glycerine)
should be used. Excess fluid is positively harmful; simply
cover the tissues.
Strict cleanliness is essential; rinse all bottles with distilled
water before using and between each change.
METHOD.
1. Excise small pieces of muscle, e. g. cat's intercostal, place
in a solution of 1 part formic acid and 3 parts filtered lemon
juice and leave in the dark for 10 minutes.
152
FEED W. GAIRNS
2. Decant solution, place tissues within the folds of the clean
towel, and press gently to absorb all excess fluid.
3. Transfer tissues to 1 per cent, gold chloride and return to
the dark for another 10 minutes. At the end of this period,
remove excess fluid by the method described in step 2.
4. Transfer tissues to 25 per cent, formic acid and keep in
absolute darkness for 24 hours.
5. Again repeat operation 2 and pass to pure glycerine.
Darkness is now no longer necessary.
The tissues may be kept in glycerine for months, if desired,
without any sign of deterioration and probably with advantage.
EXAMINATION OF TISSUES.
After the tissues have been for some hours in glycerine, place
a portion on a microscopic slide, immerse in glycerine, cover
with a cover-glass, and examine with the § objective. The
muscle-tissue will be found to be graded into certain differently
stained areas, usually a clear part on the outside, then a part
coloured bluish violet to red, and finally, if a large piece of
muscle has been taken, a more or less opaque central part. The
most productive parts are found where the clear area merges
into the blue. Make repeated change of focus and field until
a part is found showing nerve-fibres or end-plates. The nerveelements, when found, are stained an intense black colour.
Note the part where there is an abundance of these stained
fibres. Eemove the cover-glass carefully, then gently separate
off, from the remainder, the part selected. Remount in glycerine.
If necessary, on examination, repeat this process of selection.
It will be noted that teasing the tissue is not advised, as this
may break up the large tree-like processes of the nerve-fibres.
The specimen thus obtained may be rendered permanent by
ringing the cover-glass with a mixture of equal parts warmed
Canada balsam and melted paraffin wax or some other suitable
ringing medium.
Although this method is chiefly intended for the demonstration of motor nerve-endings in skeletal muscle, it is, as the
photomicrographs (which have not in any way been retouched)
show, very effective with other types of nerve-fibres and endings.
GOLD CHLORIDE METHOD
153
Incidentally, it may be noted that if one desires to demonstrate the myenteric plexus, either the muscle-coats of the
intestine should be separated off before treating the tissues,
or alternatively remove as much of the mucous membrane as
possible before treatment and strip off the rnuscle-coats when
in glycerine. This can easily be managed with a pair of forceps.
The intestine of the rabbit should be used in preference to that
of the cat, as the intestinal muscular coat of the latter is too
thick.
My thanks are due to Professor E. P. Cathcart and to
Dr. A. McL. Watson for their kindly advice and help. I wish
also to thank Mr. J. E. Bell for the patience and care he has
taken in preparing the photomicrographs.
March, 1930.
DESCRIPTION OF PLATES 7 AND 8.
Kg.
Fig.
Fig.
Fig.
Fig.
Fig.
Fig.
Fig.
Fig.
Fig.
Fig.
Fig.
1.—Node of Ranvier (oat). X 250.
2.—Motor end-plates : intercostal muscle (cat), x 60.
3.—Motor end-plates : intercostal muscle (cat). X 250.
4.—Nerve-endings : gluteus maximus (cat). X 250.
5.—Part of muscle spindle : intercostal muscle (cat). X 250.
6.—Organ of Golgi: gluteus maximus (cat), x 60.
7.—Organ of Golgi: gluteus maximus (cat), x 250.
8.—Pacinian body : mesentery (cat). X 60.
9.—Auerbach's plexus : small intestine (rabbit). X 60.
10.—Auerbach's plexus : small intestine (rabbit). X 250.
11.—Meissner's plexus : small intestine (rabbit). X 250.
12.—Ganglion cells : urinary bladder (cat), x 60.
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. Jou^n. MUyr. Sci. Vat 74-,N.S.,4t.8