Table 10.— Reactive frequency of chinook salmon sera reacting with 

 Robinia pseudoacacia bark extract 



X = 75 (i percent significance level with 5 d.f. = 30) 



mune antibodies. Using strictly fresh material 

 precluded this phenomenon from interfering 

 with results obtained on the nonsalmonid 

 species tested. The presence of the phenomenon 

 in salmonids, however, suggests that the aging 

 of cells is a limiting factor in the usefulness 

 of phytoagglutinins in fish blood typing work. 

 Therefore, one should be cautious in inter- 

 preting results of tests with these extracts 

 unless fresh cells are being used or previous 

 work has shown that storage of cells does not 

 alter the reaction. Sprague and HoUoway (1962) 

 have also commented on the variability of 

 reactions obtained when tuna cells are agglu- 

 tinated with various plant extracts. 



Further research is necessary before the 

 potentialities of phytoprecipitins in fishery 

 research can be properly assessed. Relation- 

 ships to immune precipitins and genetic im- 

 plications of their variability are unknown. It 

 is of interest, however, that such variabilities 

 do exist and that they can be studied in the 

 same manner as those detected by immune 

 antisera. The apparent geographic variation of 



the reaction oi chinook salmon sera with 

 Robinia pseudoacacia bark extract is certainly 

 of practical interest. It seems probable that 

 similar plant extract-fish serum relationships 

 exist which are capable of analysis by the 

 double diffusion technique. This variation is 

 probably an expression of a basic genetic dif- 

 ference in these populations since it is inde- 

 pendent of sex and all individuals were collected 

 at the same stage of maturity. Effects of diet 

 are also excluded because these fish had 

 ceased feeding. 



SUMMARY 



1 . Phytoagglutinins extracted from the seeds 

 and bark of various legumes were shown to 

 possess a variety of specificities against fish 

 erythrocytes, some of which detected intra- 

 and interspecies differences. 



2. Significance of individual variations found 

 in salmonids is complicated as a result of 

 alteration of reactive strengths of cells on 

 aging. 



15 



