PROCEEDINGS OF THE SOCIETY. 
137 
Several years ago lie was vory much interested in the Nudibranchs 
find very greatly admired the beautiful colours of some species of Eolis , 
but found that when placed in alcohol in order to preserve them their 
colour was removed, and this of course rendered them very much less 
attractive in appearance as well as less valuable for illustrative purposes. 
It. therefore occurred to him that perhaps something might be done to 
remedy this, and that if they could be preserved and mounted as lantern 
slides to be shown on the screen with their natural colours, it would be 
of great advantage. His attempts to do this turned out very successful ; 
the only principal group of animals he had not been able to succeed with 
was that of the Actiniae. Different plans, of course, had to be adopted in 
different cases, experience soon showing what was best for each ; but the 
plan generally followed was to kill the specimens by putting them into 
alcohol and water, not leaving them long enough to injure the colour, 
but to get rid of the salt water, and then to arrange them carefully in 
the position it was desired to show them upon a piece of lantern-glass, 
and allow them to dry. There was in most marine animals a certain 
amount of mucus which caused them to adhere to the glass, and the great 
secret of success lay in the fact that they dried at the edges first and 
became fixed, and no change in the outline took place as the drying pro- 
ceeded, the only alteration being that they got thinner. In some cases 
in which the colouring matter is dissolved out by alcohol or by Canada 
balsam ; when mounted in balsam the red colour comes out and blurrs 
the outline as well as spoils the ajrpearance generally. This disadvan- 
tage was, however, overcome by carefully coating the specimen with gum 
arabic, allowing the gum to thoroughly soak into it, and when this was 
dry the animal was so perfectly protected from the balsam that it could 
then be permanently mounted in that medium without undergoing any 
change whatever, except the slight change which took place immediately 
after it was killed. In this way they got the beautiful purple Eolis prel 
served with its red colour intact, and rendered so transparent that when 
shown on the screen everything was seen to great perfection. Speci- 
mens mounted in this way had kept perfectly good for six years and 
showed no signs of change. Small flat fish were much more easily dealt 
with, and it was quite surprising what excellent slides could be made 
with young soles, plaice, or dabs up to as much as 2^ in. long. All it 
was necessary to do was to arrange them on the glass and let them dry, 
then soak them in benzole and afterwards to mount them in Canada 
balsam, where they became so transparent that every detail could be 
seen when used as lantern slides, and a great deal more of their internal 
structure than it was possible to see in the living fish. He hoped he 
might on some future occasion be able to show the Society some of the 
results of this method of preparation. 
In connection with this matter he had carried out a great many ex- 
periments in staining, the object of this being to bring out such 
characters as could be seen when thrown upon the screen. He had got 
some very good results in this way with Medusae, and though they 
looked at first rather unpromising, they in most eases turned out very 
well. In their case the first thing to be done was to put them into a 
mixture of methylic alcohol and water — about half of each — and to 
change this until all the salt was dissolved out. It was absolutely 
