| 摘要 |
<p>A cylindrical test tube pref. of glass or synthetic material sealed by a stopper engaging between two annular tips onto a peripheral projection on the test tube. The penetration of the stopper may be adjusted to either lip, the lower position effecting a watertight seal, the upper positon allowing communication between the interior and external atmospheres via vertical peripheral passages in the lip and projection. The stopper is pref. moulded to form two concentric grooves the lip of the tube being slideable into the inner groove.</p> |
