100 
Transactions of the 
[Monthly Microscopical 
Journal, Feb. 1, 1869. 
others, and as I now work it, preparations can be prepared just 
as quickly in this way as by any of the others. I first got a hint 
as to the possibihty of preparing nerve-tissue in this way about 
eighteen months ago, owing to a quite accidental efiect produced 
whilst making some experiments at that time. But for a long 
time the production of this effect was so much a matter of chance, 
that ; I said nothing on the subject in the paper in the ' Journal of 
Anatomy and Physiology,' and it is since that time more especially 
that I have striven to perfect it so as to make it yield more 
constant and uniform results. In this I have succeeded to a 
certain extent. No advantage whatever is derived from tinting 
when this method is employed, since the characteristic effect of the 
method is that it throws the nerve-cells and their ramifications 
into great prominence, whilst at the same time it subordinates the 
intermediate granular-looking material, and enables us to resolve 
this into its ultimate elements. 
At first I obtained this effect by saturating the section in strong 
spirits of wine for a time, then suspending the section from the tip 
of a scalpel (after having removed superfluous spirit with blotting- 
paper) till it became quite dry and began to shrink. The section 
was then placed in a drop or two of chloroform on the glass slide, 
which caused it immediately to regain its form and become more 
or less transparent. During this time it was examined under a 
low power of the microscope, and when the characteristic effect 
was brought out, the superfluous chloroform was tilted off, some 
solution of Canada balsam in chloroform poured over it, and the 
covering-glass was then applied. When I first began to operate in 
this way the weather chanced to be dry, with very little moisture 
in the air, and the results were fairly good; but when, after an 
interval of a month or so, I again began to prepare sections by 
this method, every attempt was a failure, and it was not till I had 
spent many days in all kinds of trials with fresh spirit, fresh 
chloroform, &c., that I became convinced that my failures were due 
to the humid state of the atmosphere. It was in mid- winter, and 
there had been a constant succession of wet days. It seemed that 
the section, during the process of drying, had imbibed a certain 
amount of moisture from the air, and it was the presence of this 
that made the sections, after the application of chloroform, perfectly 
dark and opaque, instead of more or less transparent. Then I 
felt that it would not do to rely upon the drying process in a 
climate such as ours, and I sought to bring about the same result 
in other ways.* After innumerable experiments with different 
* So far as I can understand the effects produced by this method, I am in- 
clined to tbink that they depend upon the presence of a very minute quantity of 
water still remaining in the section, and principally in the nerve-fibres, the nerve- 
cells, and their ramifications. These probably would be the last portions of the 
