抄録
As the material of experiments the author has chosen Salmo irideus GIBBONS and Oncorhynchus masou (BREVOORT). The first method adopted was to select a parent fish and keep it for several hours or several days in a weak solution of lactic acid (0•0025-0•015%) or of soda (0•15-0•3%). Subsequently, taking the female or male generative matter out of it, the normal male or female generative matter was matched, as follows:- ?? (acid)× ?? (normal); ?? (acid)× ?? (acid); ?? (normal)× ?? (acid); ?? (soda)× ?? (normal); ?? (soda)× ?? (soda); ?? (normal× ?? sodia); ?? (acid)× ?? (soda); ?? (soda)× ?? (acid). The second method was that, at the time of fertilization, the female or male generative matter was soaked in a solution of acid (lactic acid 0•005-0•1%) or of alkali (soda 1-2%) for 17-50 seconds, and then the normal male or female generative matter was matched with it in the 8 different combinations as above referred to.
In the above experiments the author has, for convenience' sake, termed the cases of ?? (acid)× ?? (normal), ?? (normal)× ?? (acid), and ?? (acid)× ?? (acid) the acid participation; ?? (soda)× ?? (normal), ?? (normal)× ?? (soda), and ?? (soda)× ?? (soda) the alkaline participation, and ?? (soda)× ?? (acid) and ??(acid)× ?? (soda) the inter-acid and alkaline participation.
The result of the above experiments is summarized hereunder:-
(1) In 19 cases of regular fertilization experiments, excess of male over female always occurred, the sex ratio of 4, 348 fry being on the average ?? 48•4% to ?? 51•6%.
(2) In various kinds of fertilization experiments, in which the acid solution participated, the influence brought to bear upon the newly-hatched fry was generally in favour of the female fry. Out of 48 cases, those scoring over 50% of female fry were 35, and the average sex ratio of 13, 268 fry was ?? 50•9% to ?? 49•1%.
(3) In various kinds of fertilization experiments, in which the alkaline solution participated, the influence upon the fry was generally in favour of male ones. In 47 cases of experiments, those scoring below 50% of female fry were 43, and the sex ratio of the 10, 779 fry was ?? 46•4% to ?? 53•6%, showing a remarkable excess of male over the other sex.
(4) In 16 cases of fertilization experiments, in which the inter-acid and alkaline solution participated, the influence was in favour of the male sex, as will be instanced by the fact that out of the 16 cases there were only 6 cases which scored over 50% for the female fry. It was further shown that in the 3, 416 fry the average sex ratio was ?? 47•5% to ?? 52•5%, male fry being far in excess of the female ones.
