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