Page:Life Movements in Plants.djvu/103



most suitable plant for researches on irritability of plants is Mimosa pudica, which can be obtained in all parts of the world. An impression unfortunataly [sic] prevails that the excitatory reaction of the plant can be obtained only in summer and under favourable circumstances; this has militated against its extensive use in physiological experiments, but the misgiving is without any foundation; for I found no difficulty in demonstrating even the most delicate experiments on Mimosa before the meeting of the American Association for the Advancement of Science held during Christmas of 1914. The prevailing outside temperature at the time was considerably below the freezing point. With foresight and care it should not be at all difficult to maintain in a hot-house a large number of these plants in a sensitive condition all the year round.

In order to remove the drawback connected with the supply of sufficient material, I commenced an investigation to find whether a detached leaf preparation could be made as effective for the study of irritability as the whole plant.