Why do mice whose tails were surgically removed just after birth for generations, continue to produce mice with tails?

Surgical removal of tails is an example of acquired characters in this experiment. This experiment proves that acquired characters are not inherited. Acquired characters are inherited during the lifetime. These changes occur in the non-reproductive tissues. These cannot be passed into the DNA of the germ cells. Hence, acquired characters are not inherited.

While any changes or mutation in genetic material from reproductive tissues or gametes might have resulted in any changes in mice produced in new generations.