id="id00237">* When my experiments on the effects of heat were made, I was not aware that the subject had been carefully investigated by several observers. For instance, Sachs is convinced ('Trait de Botanique,' 1874, pp. 772, 854) that the most different kinds of plants all perish if kept for 10 m. in water at 45o to 46o Cent., or 113o to 115o Fahr.; and he concludes that the protoplasm within their cells always coagulates, if in a damp condition, at a temperature of between 50oand 60o Cent., or 122o to 140o Fahr. Max Schultze and Khne (as quoted by Dr. Bastian in 'Contemp. Review,' 1874, p. 528) "found that the protoplasm of plant-cells, with which they experimented, was always killed and [[page 67]] altered by a very brief exposure to a temperature of 118 1/2o Fahr. as a maximum." As my results are deduced from special phenomena, namely, the subsequent aggregation of the protoplasm and the re-expansion of the tentacles, they seem to me worth giving. We shall find that Drosera resists heat somewhat better than most other plants. That there should be considerable differences in this respect is not surprising, considering that some low vegetable organisms grow in hot springs—cases of which have been collected by Prof. Wyman ('American Journal of Science,' vol. xliv. 1867). Thus, Dr. Hooker found Confervae in water at 168o Fahr.; Humboldt, at 185o Fahr.; and Descloizeaux, at 208o Fahr.) [page 67]

[My experiments were tried in the following manner. Leaves were cut off, and this does not in the least interfere with their powers; for instance, three cut off leaves, with bits of meat placed on them, were kept in a damp atmosphere, and after 23 hrs. closely embraced the meat both with their tentacles and blades; and the protoplasm within their cells was well aggregated. Three ounces of doubly distilled water was heated in a porcelain vessel, with a delicate thermometer having a long bulb obliquely suspended in it. The water was gradually raised