A reduction of the intervening distance will give rise to a different result. As the negative response is the more intense of the two, the feeble positive will be masked by the superposed negative. The separate exhibition of the two responses is only possible by a sufficient lag of the negative impulse behind the positive. This lag increases with increase of length of transmission and decreases with the diminution of the length. Hence the application of stimulus near the responding organ will give rise only to a negative response, in spite of the presence of the positive, which becomes masked by the predominant negative.[P] [P] _Cf._ BOSE--“Plant Response,” p. 535; “Comparative Electro-Physiology,” p. 64; “Irritability of Plants,” p. 196. These inferences have been fully borne out by results of experiments carried out with various specimens of plants under the action of diverse forms of stimuli. In all cases, application of stimulus at a distance causes a pure positive response; moderate reduction of the distance induces a diphasic response--a positive followed by a negative; further diminution of distance gives rise to a resultant negative response, the positive being masked by the predominant negative. From what has been said it will be understood that the exhibition of positive response is favoured by the conditions, that the transmitting tissue should be semi-conducting, and the stimulus feeble. It is thus easier to exhibit the positive effect with the feebly conducting petiole of _Averrhoa_ than with the better conducting petiole of _Mimosa_. It is, however, possible to obtain positive response in the _Mimosa_ by application of indirect stimulus to the stem in which conduction is less rapid than in the petioles. TABLE IX.--PERIODS OF TRANSMISSION OF POSITIVE AND NEGATIVE IMPULSES IN THE PETIOLE OF _AVERRHOA_ AND STEM OF _MIMOSA_.