138 
PROCEEDINGS OF THE SOCIETY. 
necessary to get rid of this, as otherwise it would crystallise and spoil 
everything. It was very important, in staining these animals, to choose 
SJme colouring matter which was adapted for the purpose in view, and 
it by no means followed, as he found by experience, that what was a 
good staining material for microscopic work was necessarily the best in 
the preparation of lantern slides. Carmine stained very well, but made 
them rather too smart, and he found, after various trials, that nothing 
was more satisfactory than a tincture of madder in alcohol, which dif- 
ferentiated the parts very well and gave very good results. In dealing 
with Medusae care was required in the drying process, because they 
cracked off from the glass if dried in the ordinary way ; but it was 
possible to succeed very well by treating them with gum as they dried, 
and keeping them moist until the gum had thoroughly soaked in. At 
first he found there was great trouble caused by the growth of mould 
upon the damp surface, which, amongst other inconveniences, altered the 
colour of the stain and very much spoilt the general effect, but, after a 
few attempts, he found he could keep them damp for weeks and months 
by putting them into a develop in g-glass covered with a piece of plate- 
glass, over some alcohol diluted with water. The vapour of the alcohol 
did not in any way affect the gum, whilst it effectually prevented the 
growth of mould and allowed the specimen to be kept damp for as long 
as desired. 
With animals which had red haemoglobin, it was surprising to find 
that in some cases, after being mounted in Canada balsam, it underwent 
no change whatever for years, so that specimens of marine worms, with 
their vessels injected with their own blood, were just as good at the 
present time as they were when first mounted. 
In preparing Arenicola the best way was to slit the animal from end 
to end and turn the viscera to one side so as to show the principal blood- 
vessels and the branch blood-vessels supplying the branching, and after 
being mounted in balsam, these parts could be shown with their per- 
fectly natural colours, and in a very satisfactory manner. 
Some of these creatures were very delicate, and he had been trying 
this year, not merely to preserve their larger vessels, but to preserve 
the whole of the blood-vessels, a matter of very great difficulty, because 
if .there was the slightest lesion the whole attempt was a failure. It 
seemed necessary to be able in some w r ay to sterilise them, and he had 
therefore tried to keep them in some medium which would have this 
effect without killing them. He found that a solution of benzote of 
ammonium was one of the best things he had tried, though a solution of 
ordinary galls answered very well, the effect being to, as it were, tan 
them whilst alive. He had succeeded so well at last in preserving some 
of the common Nereis as to show, if not all, certainly the larger part of 
the blood-vessels. In some species he found that the animals from one 
locality differed very much from those met with elsewhere, and contained 
comparatively few blood-vessels. 
One point more he should like to mention in connection with the 
subject, because it was the very opposite to staining. He found that 
there were a number of animals which were too opaque through there 
being too much colour about them, so that in the lantern they showed 
like dark shadows. Others became dark after a time, although not so at 
