The vials were sealed with airtight rubber stoppers.
The leaf that was nearest to the tip of the stick was cut and stored in an airtight plastic bag.
To maintain a higher humidity (60+5%), the vials were kept inside an airtight plastic container.
While insulation and greenhouse significantly reduce air convection, neither of these layers is sealed completely airtight.
Despite the continuing publication of textbooks presenting this airtight canon, however, cracks have appeared with ever-greater frequency.
An airtight seal within the pump and tubing is crucial to the success of vacuum extraction.
Regulations governing the reporting of causes of death were not entirely airtight.
The cases could not have been "hermetically sealed"; if airtight, the plants would long since have died.
