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190 water, the variation of temperature should not be too sudden; it should commence with tepid, and end with. warm water. Sudden application of hot water brings about certain complications due to excitatory effect. As regards the per- sistence of after-eti'ect of a single application of warm water, it. should be remembered that the absorbed water gradually cools down. In an experiment with a peduncle of Zep/ryrrmé/ms tho growth under partial drought was found to be (Hit ,1. per second ; application of warm water increased the growth rate to 0'20 [1. per second. After 15 minutes the growth rate fell to 0'13}; per second; and after an hour to (NH ,1. INT second. It will be noted that even then the rate was twice the initial rate before irrigation.

TABLE NILMEI’I’EWI HF IRRIGATION.

Specimen. (’mnllt'ul):v”f EH” “- Rate of growth. nt. l I l i [Cg/sour ' Dry soil  0'21 [L per second. I rrigation with Gold , i \V'Itit'l‘  0'30 a .. .. Irrigation with warm i \Vntl‘l‘ ... ... 1‘33 )1. ,. ,, I’vdunclo of er/Iy-E Dry soil  0'04 [1. ,, ,, rant/um.  Irrigation with warm I; water   0°20 IL ,, ,,

Increasnd turgor was, next, artiﬁcially induced by increase of internal hydrostatic pressure.

hirperiment 71.-—-'l‘hv plant was mounted water-tight in tIu- short limb of an U-tube, and subjected to increased hydrostatic pressure by increasing the height of the water