Temperature as a factor in the determination of sex in amphibians / Helen Dean King.
- Helen Dean King
- Date:
- 1910
Licence: In copyright
Credit: Temperature as a factor in the determination of sex in amphibians / Helen Dean King. Source: Wellcome Collection.
Provider: This material has been provided by The Royal College of Surgeons of England. The original may be consulted at The Royal College of Surgeons of England.
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![[Reprinted from Biological Bulletin, jfol. XVIII., No. 3, February, 1910.] * v A ^ - id TEMPERATURE AS A MINATION OF SEX I DETER- BIANS. HELEN DEAN KING, Assistant in Anatomy at the Wistar Institute. In 1905, Hertwig (1) published the results of a series of experi- ments on the eggs of Rana temporaria and of Rana esculenta which showed, according to his interpretation, that temperature is a sex-determining factor in amphibians: a high temperature favoring the development of females ; a low temperature causing the production of relatively more males. This conclusion is in accord with the results of Issakowitsch’s (2) earlier experiments on sex-determination in Daphma ; but it is opposed by the results of Maupas’ (7) experiments on Hydatina senta and by those of von Malsen (6) on Dinophilus apairis. The latter experiments seemed to indicate that heat leads to the development of males and that cold tends to the production of females. Maupas and Hertwig believe that temperature acts directly on the sex-cells : Issakowitsch and von Malsen, on the other hand, maintain that nutrition is the dominant factor in sex-determination, temperature acting only indirectly through its influence on the processes of assimilation in the parent organism. In the spring of 1907, I made a series of temperature experi- ments on the eggs of the toad, Bufo lentiginosus, which were carried out in a manner similar to those made by Hertwig on the eggs of Rana. Various lots of fertilized eggs were placed in tanks in which the water was kept at a nearly constant tempera- ture until the tadpoles underwent metamorphosis (King, 5). In Bufo as in Rana, the sexes cannot be distinguished until the end of metamorphosis unless the gonads are sectioned. It is con- ceivable, therefore, that sex in these forms may not be determined until a relatively late period and that temperature, acting during the entire growth period of the tadpoles, might alter the normal sex-ratio. Two series of experiments were made with eggs from different females. In one series (lot A) 62.5 per cent, of the in-](https://iiif.wellcomecollection.org/image/b2241776x_0005.jp2/full/800%2C/0/default.jpg)
