FIG. 1 illustrates an infusion device 11 constructed of a housing 12 or pressure containment pouch of flexible, substantially nonextensible (i.e., substantially nondistendable) tubing material, sealed at one end by a rigid compartmented base assembly 13 formed from three pieces 14, 15, 16 of a material such as rigid polyvinyl chloride (PVC) welded together by conventional means, such as ultrasonic