MISCELLANEOUS NOTES. 493 



influence at work to bleach the specimen is light, which, curious to say as the 

 exhibited specimen shews, dors not seem to have much effect. A has been ex- 

 posed to the full influence of a tropical light ever since 1884. Reflecting on this 

 aotion it occurred to me, if the exclusion of air and moisture is the great ideal 

 to aim at, could not some substance of a lighter specific gravity than glycerine 

 In' found P Why not some kind of oil ? and of course in Ceylon cocoa-nut oil first 

 suggested itself. But cocoa-nut oil, far from being likely to be a preservative, 

 would require preserving itself. How was this to be done ? Would carbolic acid 

 mix with it ? I found on experimenting that carbolic acid mixed with it in all 

 proportions. There was, of course, no idea of using this as a preservative, the 

 specimens must be first prepared. Very fluid arsenic paste was used for silvery 

 fish with some success, and reduced gum and glycerine and gelatine — of which 

 K is an example — were also tried ; but from the very first it proved a very re- 

 fractory mounting medium. It was very difficult to get a sufficiently white oil 

 to begin with, and when I did, it always had a strong tendency to discolour. 

 Time has proved I need not have troubled myself; it cannot be usedas a mounting 

 medium as mixtures of carbolic acid and glycerine, or cocoa-nut oil, attain a deep 

 colour in time, irrespective of any animal matter in them. L shews the action 

 in the case of glycerine ; M in the case of oil. You will see in this latter case 

 that the toad is in splendid preservation, and the fluid bright and clear, but the 

 colour is very objectionable. Whole cases filled with bottles of this tint would 

 be very ugly, although if the animals and their colour were well preserved, they 

 might be more instructive than ordinary specimens. There was, however, 

 another difficulty ; a very fine cobra, well hardened in spirit after some months, 

 broke down from no apparent cause ; it was also found impossible to get a com- 

 mon blood-sucker mounted in this medium. Neither k gum and glycerine, nor 

 strong spirit, nor arsenic paste, nor anything else could keep them. In fact the 

 medium appeared either not to be safe or not universally applicable. In order 

 to study it and learn what its action really was, I preserved a blood-sucker in it 

 direct, without previous preparation of any kind, and found that I had a preserva- 

 tion of form as good as any known, and of colour' as good as gum and glycerine 

 itself. In this case the carbolic acid is either the dehydrater, or perhaps combines 

 with the tissues and preserves them, whilst the oil acts as the atmospheric ex- 

 cluder; and nowyou will see why difficult subjects such as cobras andblood-suckers, 

 previously prepared, broke down. The tissues had absorbed from the alcohol or 

 arsenic paste, or reduced gum and glycerine, a large proportion of water, in 

 addition to that naturally contained in them, and consequently -more than the 

 carbolic acid could extract or combine with, the result being that they had an 

 atmosphere, so to speak, of their own, which finally led to their more or less 

 speedy decay. Here is then a splendid medium for the zoologist, especially in a 

 hot climate. He is furnished with a powerful and easily used preservative both 

 for form and colour which does not evaporate. N, the leg of a fly laid on a 

 glass slide in a drop of oil, and just simply covered by an ordinary microscopic 

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