again giving a good response when tested ,Noo »:81»o A third portion 

 was adjusted to pH 9 with axnmonium hydroKide;, passed through a 

 weakly basic jDuolite A-3* ajiion exchange column^ and the adsorbed 

 material was eluted with weak ammonium hydroxide and testedj, giv = 

 ing a positive but weak response (NOo ^82io The unadsorbed iiltratep 

 however^ gave a stronger response |Noo 283)o Apparently there was 

 only partial separation of the active substance on the anion exchangerc 

 The fact that the results were generally positivCo as compared with 

 the negative results of the previous serieSj, is surprising as they 

 were based on a second and presum.-ibly weaker alcohol extraction of 

 the same material as was used previouslyo The main differences 

 were the precipitatfon of lead with hydrochloric acid rather than 

 sodium chloride and the elimination of the cation exchanger „ neither 

 of which should have led to the differences o They may have been 

 caused by either aberrant fish behavior or slight differences in 

 techniqueo 



In a third alcohol e3etraction of the same tuna flesh as 

 used previously »ifig<, 15% the filtrate was treated with lead acetate^ 

 filter edj the filtrate was treated with hydrochloric acidp filter edp the 

 filtrate was adjusted to pH 7„ passed through a strong ; Amberlite 

 IR-120) cation exchangerj, and the filtrate of pH Z was tested with 

 negative results (No, 285, „ When the filtrate from the cation ex-^ 

 changer was adjusted to pH 8 with ammonium hydro>ide„ there was 

 a positive response ?NOo 286'o When the materisil adsorbed on the 

 cation exchanger was eluted with weak acetic acid and tested^ it 

 gave an even stronger response (NOo Z87>o Again^ the results are 

 puzzlingo On prior testSo the attractant had not been adsorbed (to 

 any great extents, at least) on the cation exchanger o For the materi-= 

 al that was not adsorbedp the attractive qualities seemed to be lost 

 at a low pHo 



At this time it was suspected that the variability and 

 inconsistency of the results might hdive some relationship to the pH 

 of the materials -ind the length of time »^hey were subjec 'o extremtrS 

 of pHo In passing through cation and Anion exchangers;, and in other 

 treatments which were usedp pH s ranging from 2 to 12 were cGn\ = 

 monly induced for varying periods of timeo 



Several preliminary experiments with skipjack v.scera 

 preparations (NoSo 288^ 289, 290; No&. 295, 296„ 297? and bigeye 

 flesh preparations (Nos, 292^, 29 5^ 294'i m which e>tracts exposed 

 to pH's of 2^ 7j and 10 were compaiedj gave inconsistent results 

 but suggested that the response might be less at the two extremes; 

 the mean tobservationalj scores for the three sets of experiments 

 listed above were UO^ l,8j and 1„ 5 for pH-s of 2p 7, and 10^ 

 respectively;, 



53 



