From The Collaborative International Dictionary of English v.0.48:
Bleb \Bleb\, n. [Prov. E. bleb, bleib, blob, bubble, blister.
This word belongs to the root of blub, blubber, blabber, and
perh. blow to puff.]
A large vesicle or bulla, usually containing a serous fluid;
a blister; a bubble, as in water, glass, etc.
[1913 Webster]
Arsenic abounds with air blebs. --Kirwan.
[1913 Webster]