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The Effects of Alcohol Not Inherited in Hydatina Senta

D. D. Whitney
The American Naturalist
Vol. 46, No. 541 (Jan., 1912), pp. 41-56
Stable URL: http://www.jstor.org/stable/2455551
Page Count: 16
Subjects: Biological Sciences Ecology & Evolutionary Biology
Find more content in these subjects: Biological Sciences Ecology & Evolutionary Biology
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Abstract

1. Four strains of parthenogenetic rotifers originally descended from the same female were observed throughout twenty-eight successive generations. One strain was kept as a control and the other three strains were kept in a per cent., a 1/2 per cent and a 1 per cent. solution of alcohol. The rate of reproduction was lower in the alcoholic strains than in the control and it was proportionally lowered according to the amount of alcohol used. 2. The individuals of the 1 per cent. alcoholic strain in the XI-XV generations showed a decidedly increased susceptibility to copper sulphate. 3. When the alcohol was removed in generations XIX-XII, the rate of reproduction increased noticeably in the first generation and in the second generation the reproduction rate equaled that of the control. 4. Individuals of the second generation after the alcohol had been removed were no more susceptible to copper sulphate than individuals which had never been subjected to alcohol. 5. The general conclusion is that alcohol in 1/4 per cent., per cent., and I per cent. solutions is detrimental to this race of rotifers when it is subjected to it continuously for many generations. The weaknesses developed by the parental use of alcohol are partially eliminated in the first generation after the alcohol has been removed, and practically completely eliminated at the end of the second generation after the alcohol has been removed. In other words, the grandchildren possess none of the defects caused by alcohol in the grandparents. 6. These results in general show that alcohol in the percentages used affects only the somatic tissues of the animal, and if they are subjected to its influences indefinitely, generation after generation, the race would probably become extinct because of its "lowered resistance power" to unfavorable conditions. However, if the alcohol is removed it is possible for the race to recover and to regain its normal condition in two generations, thus showing that the germ substance is not permanently affected by the alcohol.