For the second time in two years, Superman loses his memory in Superman #32 (November 1944). This time, it’s a new brain tissue analysis machine and Superman, wishing to further science, volunteers only to discover too late that his brain is actually vulnerable. This is the first time Superman tries to piece together his own back-story and does not realize his secret identity is Clark Kent. This turns out to be a fun trope that is revisited in years to come as the writers struggle to keep the Superman stories interesting.
Lois has come a long way in six years. Remember she used to openly loathe Clark Kent.