Yea just do it in a loop and put the objects into a list:
drops = []
for line in file:
x, y, z, t = parseFromFile(line)
drops.append(Droplet(x,y,z,t))
or, more Pythonesque:
drops = [Droplet(*parseFromFile(line)) for line in file]
*
here takes the (presumbably four) values returned by parseFromFile
and uses them as four arguments for the Droplet
instantiation