A method and apparatus for using a gaseous unsaturated hydrocarbon, or oxide thereof, as a yield stimulant by its direct absorption into the lie bark tissues of Hevea brasiliensis are described. A polyethene or rubber jacket sealed to the tree bark is used for holding the stimulant. This prolongs latex flow, when a hypodermic puncture is made in the bark, for upto 40 h. or more at a maximum rate of one ml per minute. The latex is collected by means of a hollow tube or needle (of about one mm internal diameter) that leads into a covered latex collection container, form the hypodermic puncture. The total outflow of latex from one aperture was between 1000 ml and 2000 ml per extraction, compared to only about 150 ml obtainable from conventional half spiral tapping systems. The higher yield realized by this method promises a bright future for the natural rubber industry. Physiological parameters relevant to sucrose translocation and its subsequent synthesis into isoprene in situ were also monitored over a period. The physiological dynamics of this convention of sucrose into isoprene is also discussed briefly. Anatomical examination of stimulated bark samples taken from trees under the new method of latex extraction did not indicate any undesirable effects. Microscopic observation of the stimulated bark samples indicated no decease in the number of healthy latex vessel rings.