It is unfortunate that the effect of food cannot be separated from the 

 possible effect of the time component (Weeks), although It is difficult to see 

 how the latter, if a regression, could lead to a significant interaction with ex- 

 tract. The inclusion of the blend extract data has contributed to the interaction. 

 However, the interaction is still significant if these data are excluded from the 

 calculations. The response to squid extract was greatest when the fish were being 

 fed squid. The response to skipjack extract was greatest when the fish were being 

 fed skipjack. The response to shrimp extract was greatest when the fish were 

 being fed skipjack, but it was greater when they were fed shrimp than when they 

 were fed squid. The differential response indicates a degree of conditioning of 

 the fish to a particular food substance. In part, this may explain the weaker 

 responses to skipjack flesh and viscera extracts during July 1953 as compared with 

 the summer of 1952, for in 1953 they were being fed squid whereas in 1952 they 

 were being fed tuna flesh. 



On completion of the experiments on conditioning the tunny were fed 

 skipjack flesh three times a week. Additional experiments indicated no signifi- 

 cant difference in response between extracts of light red (#469, 473, 478, 484) 

 and dark red (#470, 472, 480, 482) skipjack flesh. 



Alcohol extracts of skipjack flesh seemed to elicit a much weaker 

 response than aqueous extracts (see #475 to #489). This was the case when the 

 alcohol extracts were tested without further processing and also when they were 

 evaporated to dryness and redlssolved in water. The reason may be that the 

 "attractant" was only partially extracted with alcohol; this was suspected to be 

 true in some of the preparations used in 1952-53 (Tester et al. 1954). 



Response to Chemical Compounds 



The following chemicals in solution or suspension were teste'd during the 

 summer of 1953: 



Adenylic acid, muscle (#517) 



Alanine, alpha DL (#450) 



Amyl caproate (#505) 



Amyl cinnamate (#372) 



Anethol (#427) 



Anisic aldehyde (#365) 



Arglnlne monohydrochloride, L (#428) 



Asparaglne, DL (#426) 



Aspartlc acid, L (#453) 



Aspartic acid, DL (#463) 



Astrotone (#515) 



Bologna flavor (#411) 



Betalne (#474) 



Blood fibrin (#523) 



Butter flavor (#413) 



Butyric acid, alpha amino n (#455) 



Cadaverlne dlhydrochlor ide (#500) 



Calcium pantothenate, D (#493) 



Casein (#512, 524) 



Casein hydrolysats (#522) 



Chlorophyll (#459) 



Chollo acid (#495) 



lonlne C-1 (#506) 



Isoeugenol (#410) 



Lactultumln (#521) 



Leucine, DL (#430) 



Liver extract concentrate (#499) 



Liver fraction "L" (#497) 



Lysine monohydrochloride (#466) 



Lysine monohydrochloride, L (#451) 



Mercaptan, phenyl ethyl (#516) 



Methionine (#390) 



Musk ambrette (#503) 



Musk ketone (#498) 



Musk xylol (#504) 



Norvaline, DL (#455) 



Ornithine monohydrochloride, DL (#468) 



Phenylalanine (#491) 



Phenyl ethyl alcohol (#509) 



Proline, L (#457) 



Pyridoxine hydrochloride (#462) 



Riboflavin (#510) 



Serine, DL (#429) 



Sodium bisulphite (#449) 



