Most bacteria can be stained with postitevly charged stains.So this is true .My friend had a test about this so he told me all about this topic and helped me learn about it and help you.
I am almost entirely sure that DNA testing had not been discovered at this time, but regardless of whether that is true, the very first criminal case that DNA testing was used in occurred in 1985. So no, it was not used commonly in the 20's.
