Abstract: A device for independently controlling the temperature and/or relative humidity in the gas utilized in connection with a life support system formed by a chamber bounded by a bottom wall, side walls, and a top wall, one of the walls of the chamber provided with a gas inlet and a gas outlet, gas spider means associated with the gas inlet and providing gas passageways for segregating portions of the gas introduced into the device through the gas inlet, gas proportioning valve means positioned in association with the gas spider means and in line with the gas inlet to permit independent variable proportioning of the gases to at least two downline gas passageways, at least a first gas passageway traversing the gas spider means and terminating at the gas outlet and a second gas passageway traversing the gas spider means and in fluid communication with the chamber, the gas outlet being in fluid communication with the chamber and with the first passageway in the gas spider means, the chamber being adapted to hold a qu