** It appears that cold-blooded animals are, as might have been expected, far more sensitive to an increase of temperature than is Drosera. Thus, as I hear from Dr. Burdon Sanderson, a frog begins to be distressed in water at a temperature of only 85° Fahr. At 95° the muscles become rigid, and the animal dies in a stiffened condition. [page 75] water does not cause any inflection: I suddenly placed four leaves, taken from plants which had been kept for several days at a high temperature, generally about 75° Fahr. (23°.8 Cent.), in water at 45° (7°.2 Cent.), but they were hardly at all affected; not so much as some other leaves from the same plants, which were at the same time immersed in water at 75°; for these became in a slight degree inflected. [page 76] CHAPTER V. THE EFFECTS OF NON-NITROGENOUS AND NITROGENOUS ORGANIC FLUIDS ON THE LEAVES. Non-nitrogenous fluids—Solutions of gum arabic—Sugar—Starch—Diluted alcohol—Olive oil— Infusion and decoction of tea—Nitrogenous fluids—Milk—Urine—Liquid albumen—Infusion of raw meat—Impure mucus—Saliva—Solution of isinglass—Difference in the action of these two sets of fluids—Decoction of green peas—Decoction and infusion of cabbage—Decoction of grass leaves. When, in 1860, I first observed Drosera, and was led to believe that the leaves absorbed nutritious matter from the insects which they captured, it seemed to me a good plan to make some preliminary trials with a few common fluids, containing and not containing nitrogenous matter; and the results are worth giving.