Page:Collected Physical Papers.djvu/413

Rh Parallel effects are also observed in regard to chemical stimulation of both inorganic and on living matter. The same reagent which In large doses causes a depression of excitability and abolition of response in metals, induces, on the other hand, a great enhancement of response when the dose is sufficiently minute (p. 301).

In the living plant, poisons produce death and permanent abolition of response. In minute doses, however, they induce a great enhancement of vital activity thus acting as a highly efficient stimulant in promotion of growth (p. 351).

The Magnetic Crescograph.—The magnification is very greatly increased by the Magnetic Crescograph which produces a magnification of about 50 million times; this order of magnification would lengthen a single wave of sodium light to 2,500 cm. (p. 357).

The Magnetic Radiometer.—This enables comparison of energy of every ray in the solar spectrum (p. 362).

A continuity of response having been established between the responses of inorganic matter on the one hand and living plants on the other, inquiry was continued to find out whether the fundamental physiological mechanisms were similar in plant and in animal life. The plant world affords an unique opportunity for studying the changes by which a simple and primitive organ becomes gradually transformed into one of greater complexity. The evolutionary process has been active not only in morphological differentiation, that is, in the