English: This glass micro-pipette was used by Joseph Lister in his experiments on the souring of milk. He discovered that milk straight from the animal is generally free from bacteria. But when examining sour milk he found that the micro-organisms present were of a type which he had previously named Bacterium lactis. The micro-pipette was designed in such a manner that it could dispense “rather less than one bacterium” per drop of diluted bacterial solution.