92 EXPERIMENTS ON THE PRODUCTION OF ARTIFICIAL BAIT. 



difficulty of finding a proper medium witli which to convey the 

 attracting smell could only be got over the problem would 

 practically be solved. — W. L. Calderwood, Director, 



In a previous number of the Journal Mr. Bateson has shown that 

 the majority of the fishes which are caught by the long lines are 

 attracted to their food entirely by smelly and it has been suggested 

 that if the odorous material could be extracted from the bait and 

 preserved, it would be possible to keep a supply of such bait in hand, 

 and so be more or less independent of the supply of natural bait, 

 which is at all times very uncertain. My first experiments were 

 mainly in this direction, to extract and preserve the odorous matter 

 from the bait, and in this I have been to some extent successful. 



Various solvents were employed for extracting. The volatile ones, 

 such as ether and chloroform, were used in an extracting apparatus, 

 while in other cases the bait, &c., was cut into small pieces and 

 soaked in the liquid at as high a temperature as could be employed 

 without destroying the scent. This temperature appears to be about 

 50° C. Ether extracts from almost all kinds of bait an oil, varying 

 greatly in quantity ; from squid and moUusca ; generally this amount 

 is extremely small and on this account quite useless, although it has 

 in some cases attractive properties. Pilchards and mackerel give a 

 relatively large amount of extract, owing to their oily nature ; but 

 although these are to some extent attractive, they do not appear to 

 contain anything like the total amount of odorous matter present in 

 the animal. Nereis and Arenicola (as worm baits) give ethereal 

 extracts which are attractive to some fish — turbot, rockling, pouting, 

 &c., but the conger is not attracted by them. Chloroform extracts 

 nothing from mollusca, and in no case was an extract having 

 attractive properties prepared with this solvent. Olive oil and fats 

 do not take up the scent from any of the baits mentioned. Distilla- 

 tion of the baits in water, or in a current of steam, only gives a smell 

 of cooked fish, which is utterly unattractive. 



Besides extracts of the baits usually employed, I have also prepared 

 some from coarse fish ; from the intestines, livers &c., of ling, and 

 hake, and from the hermit crabs ; but have not succeeded in 

 obtaining anything at all attractive, and I believe that, if any efficient 

 extract is to be prepared, it must be from squid, mackerel, or 

 pilchard. The most attractive extracts are those prepared with 

 glycerine, but they have the disadvantage that the solvent cannot be 

 recovered or got rid of ; but, on the other hand, they can be kept for 

 any length of time if some boracic or salicylic acid be dissolved in 

 the glycerine. 



