In a similar vein

Okay, curiosity: the phrase "in a similar vein" Origins? Have seen it 'vain,' 'vane,' and 'vein'

It's vein all right. Thoughts and conversations flow as blood flows, along a path. Does "Mad" magazine still exist? Their motto was "Humor in a Jugular Vein."

It does. SS

There's even a Mad TV show now. Check your local Fox affiliate's listings for late Saturday night.