  Within a class of exact time-dependent non-singular N-logarithmic solutions
(Mineev-Weinstein and Dawson, Phys. Rev. E 50, R24 (1994); Dawson and
Mineev-Weinstein, Phys. Rev. E 57, 3063 (1998)), we have found solutions which
describe the development and pinching off of viscous droplets in the Hele-Shaw
cell in the absence of surface tension.
