A vent is formed in the flask in such manner as to prevent accidental spillage of liquid therefrom while also permitting entrance of air into the flask when negative internal pressure is applied during {HEAD ~ removal} of {TAIL ~ liquid} therefrom 
A vent is formed in the flask in such manner as to prevent accidental spillage of liquid therefrom while also permitting entrance of air into the flask when negative internal pressure is applied during { HEAD ~ removal } of { TAIL ~ liquid } therefrom
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD REL TAIL TAIL TAIL TAIL TAIL OTH