PROCEEDINGS OF THE SOCIETY. 
139 
first. Thus, for example, the almost colourless bodies of some Mollusca 
became brown, and small Sepiolas became too dark to serve useful pur- 
pose. It occurred to him, therefore, that it might be possible in some 
manner partially to bleach them, and to take away the colouring matter 
from one part, but to leave it in another. He had not yet finished his 
operations in this direction, but thought he had done enough to show 
that the process would be successful. His first attempts in this direc- 
tion were with peroxide of hydrogen, and after trying several other 
things, he thought the most satisfactory method up to the present time 
was to expose them to sulphurous acid as vapour, or in solution in water. 
He found that when so treated they did not decompose, and that an 
animal which was at first too dark, was by this process made sufficiently 
transparent to show the structure very fairly. In the Sepiolas the result 
had been very satisfactory indeed : after a week or two of this treatment 
all the natural colouring matter remained, but all the colour which had 
been formed after the creature was killed was entirely got rid of, so 
that when the specimen was mounted he was able to show the ink bag, 
and considerable portions of other internal structures. 
In dealing with almost every different group of animals, different 
methods were required, and it needed a great deal of experience and 
trouble to find out what was best suited to each. He could not yet 
altogether succeed with Actiniae, because their slime would not adhere 
to the glass, the consequence being that in drying the animals contracted 
in all directions, until they resembled a horn button, but with all the 
other groups he had tried he had found it was possible to preserve the 
specimens in very much their natural form and colour, so as to show 
well as lantern slides. He should be very glad also to be able to suc- 
ceed with some of the beautiful Nudibranclis, but these broke themselves 
to pieces in alcohol, and were of course utterly spoilt ; he should, how- 
ever, not give up the attempt, and hoped to succeed even with these. 
He hoped to be able at some future time to show the Fellows of the 
Society some of the specimens which he had endeavoured to describe, so 
that they might be able to judge for themselves as to the practical value 
of these methods of preparation. He had shown some of them at the 
Royal Society and at the Linnean Society some time ago, but he had 
many others which had been prepared since then, which he thought 
would show considerable advance. What he aimed at throughout, was 
to mount the whole animal in such a way that it could be exhibited with 
the colour it possessed when living. In order to do this, some parts 
had to be stained of their natural colour, and other portions left in the 
natural state, but by cutting the specimen to pieces, and putting it 
together again as required, and judiciously staining where necessary, the 
final result is that the preparation remains permanently of the true 
colour of the living animal, or with but very slight alteration. 
I )r. Dallinger said he had seen some of the latest specimens of Dr. 
Sorby’s work in this direction, and could say that they showed how 
greatly he had been able to advance towards perfection since his early 
attempts were made. Some of them were so excellent that it seemed 
almost incredible that they could really be the actual organisms them- 
selves, and he was quite sure that the difficulties of preparation were 
such, that if any of those present were to try to mount these things in 
