Ca. Osborne et al., FELINE URETHRAL PLUGS - ETIOLOGY AND PATHOPHYSIOLOGY, The Veterinary clinics of North America. Small animal practice, 26(2), 1996, pp. 233
Feline urethral plugs commonly are composed of large quantities of mat
rix mixed with minerals (especially struvite). However, some urethral
plugs are composed primarily of matrix, some consist of sloughed tissu
e, blood, and/or inflammatory reactants, and a few are composed primar
ily of aggregates of crystalline minerals. The formation of matrix-cry
stalline urethral plugs may be analogous to the preparation of fruit j
ello.