MR. RAY LANKESTER'S letter has reminded me of a little experiment of my own which converted me to Bastianism. I had some turnip and cheese flasks which Dr.Bastin had been kind enough to prepare in my presence, I took them home and in due time examined the contents in a good microscope, using what I thought adequate power. I saw nothing, and went triumphant to Dr.Bastian to report my failure, taking the flasks with me. Dr.Bastian looked at the fluid, smelt it, and told me he would eat his hat if it was not full of life. I thought he would have to eat his hat. He put a drop under his microscope and told me to look. It was full of small Bacteria. I was a good deal puzzled at first, but after a little discussion I found out why I had failed to see what was in the fluid. Without going into details, I may say that the short result was that I had been rather a muff with the microscope. May not this explain some other failures?—not Mr. Lankester's; of course.