After many years of work and many mouse corpses I have my
master's degree in
neuroscience.
I was introduced personally to the mouse
holocaust when I was Freshman in college and all our mice had to be killed after the educational experiments were done. I asked if I could keep one, the teacher told me I couldn't. "Fear of
animal cruelty," she said, "At least I can be sure this way that none of them die cruel deaths."
Through the years I've worked with different professors. Some decide to let the gas kill the mice, this is the kind of professor that doesn't have anything to do with the little white rodents. I don't have to be a mouse whisperer to know it is a terrible death.
I worked with a professor that literally saw the mice as simple research tools. He saw no wonder in the fact that the mice shared a significant percent of our DNA, that their cells looked a lot like ours. By holding the tail he would slam the mice against a hard, edged surface. If he was studying the body he would knock its head against something, if he were studying the brain he would break its spine. The merit of the method is that it's quick. It has led to messy deaths and damages the organs as often as not.
The best way I've found to kill a mouse is get it into a particular position, calm with its head toward you. Now, press its head down toward the ground with your hand or a spoon and pull up on its tail, brea. Because the tail is attached to its spine you easily disarticulate the head from the body. The mouse dies instantly in a calm, almost dignified position