THE AUSTRALIAN NATURALIST. 
117 
colours, for years; but it may, perhaps, gradually fade from 
the extreme top downwards, because even strong glycerine dis- 
solves a small quantity of the oxygen of the air. In glycerine 
some animals contract considerably, 
but usually only so as to 
look like smaller individuals; some become darker and alter in 
colour, especially Crustaceans, different individuals varying 
much. ‘These changes can to a large extent be counteracted 
by previous treatment with 4 per cent. formalin. 
Most of my experiments were with Solaster papposus, be- 
cause it was far the most brilliantly coloured animal I could 
procure. Seeing that the upper portion of those rays which 
were within a short distance of the air enclosed in the glass 
vessel gradually faded, whilst the rest were unchanged, I kept 
a specimen in very strong glycerine, at the top of which was a 
thick layer of almond oil. After more than five years it is even 
now more brilliantly coloured than when alive, and there is 
nothing to indicate that it would not keep much longer. I also 
find that portions of Solaster have kept well in wide-mouthed 
bottles, with little air, probably because the external air has 
been well excluded. The question is, however, whether 
rations with a layer of oil would be suitable since, if c 
handled, the oil might come into contact with 
dissolve the colour. 
Some animals, mounted as I have described in glycerine, look, 
after seven or more years, as life-like as those seen in aquaria, 
and this is surely worth the extra time and trouble to ensure 
that all the natural water has been removed, 
Quite a number, however, differ from living specimens in 
showing more colour, because they are made more transparent. 
This disadvantage is more than compensated by the internal 
structure being made visible, and the general beauty increased. 
Of these I may specially mention Ophiura, Oirratulus and many 
other. worms, which show well the legding blood vessels. Smail 
plaice, soles, and skates show well the general colour, and also 
much of the internal structure and leading blood vessels, 
In confirmation I may say I have some hundreds of marine 
animals dried, and then mounted in Canada balsam as lantern. 
slides, and this has so well protected them from atmospheric 
oxygen that few, if any, have faded in fifteen years. Ag an 
almost universal rule these preparations have improved by 
keeping, haying become more transparent. 
The importance of the exclusion of oxygen is also proved by 
experiments with solutions of vegetable colouring matters, 
which have apparently remained unchanged for about thirty 
years when sealed up in glass tubes, almost absolutely free from 
air, even resisting for a considerable time the action of strong 
sunlight, though they soon faded when exposed to the air. 
As an example of animals that I have been able to preserve 
for five years with their natural colour almost unchanged, I 
prepa- 
arelessly 
the animal and 
