250 
NOTES AND MEMORANDA. 
On the Gold Method, and the Termination of the Nerves in the 
Unstriated Muscles. — Professor Eanvier contributes the following to 
the French Academy : — Among the methods employed in histology 
for studying the final ramifications of the nerves, the gold method is 
the best. It does not, however, give constant results. The old 
methods of Cohnheim, Gerlach, and Henocque give clear and demon- 
strative preparations only by chance. The modification recently 
introduced by Lowit constitutes a real progress, for by following the 
procedure of this histologist we succeed much more frequently than 
by the old process in colouring the nerve fibrillae, whilst the ele- 
ments which surround them remain uncoloured or scarcely coloured. 
There is, however, a grave objection to this process — the solution of 
formic acid in which the fragment of tissue is placed before sub- 
mitting it to the action of the chloride of gold, notably alters its 
delicate parts. 
I have therefore sought other methods, and after many fruitless 
attempts, I have found the following, which nearly always succeeds, at 
least for some organs : — A cornea, which is an excellent subject for the 
gold method, is taken from an animal (either a mammal, a batrachian, 
or a bird) just killed. It is placed for five minutes in fresh lemon 
juice, filtered ; then it is put for fifteen to twenty minutes in three 
cubic centimetres of a 1 per cent, solution of chloride of gold, then 
in twenty-five to thirty grammes of distilled water, to which is 
added one or two drops of ordinary acetic acid. Two or three days 
afterwards, when under the influence of sunlight and the slightly acid 
medium the reduction of the gold has been effected in the cornea, 
preparations are easily obtained, in which the nervous fibrillae of the 
connective layer and of the anterior epithelium are excellently 
shown. 
Fragments of striated muscles have been treated in the same 
manner, or better, after having been subjected to the action of the 
gold, they have been placed for twelve hours, sheltered from the light, 
in a solution of formic acid of 20 per cent., and then prepared by 
teasing. The muscles of the lizards (Lacerta viridis and L. muralis) 
have given me terminal nervous arborisations, such as I have never 
obtained by the process of Lowit. These arborisations, coloured a 
deep violet, are admirably clear, and show themselves under forms 
absolutely comparable to those which I have obtained by proof 
alcohol. 
I now come to the important part of this communication, which 
relates to the termination of the nerves in the unstriated muscles. 
Histologists are not in accord as to the mode in which the nerves 
terminate in this kind of muscles. Some, as Trinchese, Franken- 
hauser, Krause, and Henocque, while differing on points of detail, 
maintain that the nerve-fibres terminate upon or in the muscular 
elements by free extremities ; the others, Klebs, J. Arnold, Lowit, 
and Gschleidlen, admit that the final fibrillae resulting from the 
division of the motor nerve constitute a network, but they do not 
agree on the form, the position, and the extent of this network. 
By means of the process above described, I believe I have succeeded 
