Sheathing for packaging a predetermined volume of a biological substance designed to be immersed in a liquid cryogenic agent

1. A kit for packaging a predetermined volume of a biological substance, said kit comprising:

a sheathing configured to be immersed in a cryogenic agent, including a thin tube having two opposed ends and an inside diameter, and

a support including a zone for receiving said predetermined volume, said support being configured to be introduced into said thin tube and having a maximum transverse dimension less than the inside diameter of said thin tube,

wherein said sheathing further includes a ballast weight associated with said thin tube only at one end of said sheathing,

further wherein said thin tube, said ballast weight and said support are configured so that, after said kit is assembled and after said thin tube is sealed at both ends, with said support introduced inside said thin tube and with said volume of substance received in said support, said sheathing self-immerses in the cryogenic agent without surface floating, including when said predetermined volume is a drop,

further wherein said ballast weight has a weight that causes said sheathing, when in the cryogenic agent, to assume a vertical orientation by the effect of said ballast weight, with the one end of said sheathing vertically below the other end thereof, thus preventing residual air contained in said sheathing from causing said sheathing to float on the surface of the cryogenic agent, and

further wherein said ballast weight is fabricated to have a given cross-sectional configuration.

2. The kit according to claim 1 , wherein said ballast weight is disposed inside said thin tube.

3. The kit according to claim 2 , wherein said ballast weight is a slug including a round cross section first portion and an oval cross section second portion ( 26 ).

4. The kit according to claim 2 , wherein said ballast weight is a ball.

5. The kit according to claim 2 , wherein said ballast weight abuts against a welded portion at one end of said thin tube.

6. The kit according to claim 2 , characterized in that there exist between said ballast weight and said thin tube holding means for holding said ballast weight in said thin tube at a predetermined position.

7. The kit according to claim 6 , wherein said holding means include at least one projecting portion of said ballast weight.

8. The kit according to claim 1 , wherein said ballast weight is disposed around said thin tube.

9. The kit according to claim 8 , wherein said ballast weight is a ring.

10. The kit according to claim 8 , wherein said thin tube has a predetermined outside diameter (De) and said ballast weight has a predetermined inside diameter less than said outside diameter (De) of said thin tube by which said ballast weight is held in place by deforming said thin tube ( 6 ).

11. The kit according to claim 1 , wherein said ballast weight is made of metal.

12. The kit according to claim 1 , characterized in that means for identifying said biological substance are associated with said ballast weight.

13. The kit according to claim 12 , wherein said identification means are visual.

14. The kit according to claim 12 , wherein said identification means are electronic.

15. The kit according to claim 1 , wherein said ballast weight gives said sheathing a heavier weight at the one end than at the other end.

16. The kit according to claim 2 , wherein at least a portion of said ballast weight has a transverse dimension greater than the inside diameter of said thin tube.

17. The kit according to claim 1 , wherein said ballast weight is fabricated to have a given length.

18. The kit according to claim 1 , wherein said cross-sectional configuration is selected to cause said ballast weight to deform said thin tube when assembled to said thin tube.