The following is a tabular statement of the different effects induced by Direct and Indirect stimulation.
TABLE XXV.—SHOWING DIFFERENCE OF EFFECTS INDUCED BY DIRECT AND INDIRECT STIMULATION.
| Stimulation. | Nature of the tissue. | Final effect. |
| Direct (Feeble) | Semi-conducting tissue. | Positive curvature. |
| Indirect " | " " | Negative curvature. |
| Direct (Strong) | Better conducting tissue. | Neutral or negative curvature. |
| Indirect " | " " " | Negative followed by positive curvature. |
The results of investigations already described, enable us to formulate the general laws of tropic curvature applicable to all forms of stimuli, and to all types of responding organs, pulvinated or growing.
LAWS OF TROPIC CURVATURE.
1. (a) DIRECT APPLICATION OF UNILATERAL STIMULUS OF MODERATE INTENSITY, INDUCES A POSITIVE OR CONCAVE CURVATURE, BY THE CONTRACTION OF THE PROXIMAL AND EXPANSION OF THE DISTAL SIDE.
(b) UNDER STRONG OR LONG-CONTINUED STIMULATION, THE POSITIVE CURVATURE IS NEUTRALISED OR REVERSED, BY TRANSVERSE CONDUCTION OF EXCITATION; THIS EFFECT IS ACCENTUATED BY THE DIFFERENTIAL EXCITABILITY OF THE TWO SIDES OF THE ORGAN.
2. (a) INDIRECT APPLICATION OF UNILATERAL STIMULUS OF FEEBLE INTENSITY INDUCES A NEGATIVE CURVATURE.