A capsule for holding a substance which is required to be held in hermetic isolation, the capsule including: a first capsule portion of flexible material for holding the substance, the first capsule portion having a closed end, an opposed open end and a predetermined length dimension defined between the ends thereof； a second capsule portion of flexible material having a closed end, an opposed open end and a predetermined length dimension defined between the ends thereof, which is shorter than the length dimension of the first capsule portion； a cap which is secured to one of the first capsule portion and the second capsule portion so as to define an additional chamber within which an additional substance is held； the closed end of the second capsule portion being located within the open end of the first capsule portion such that a region of the second capsule portion overlaps a region of the first capsule portion so as to close off the open end of the first capsule portion and define a chamber within which a substance is held, wherein the open ends of the first capsule portion and the second capsule portion are aligned flush with one another.
