All infections, of whatever type, with no exceptions, are products of parasitic beings; that is, by living organisms that enter in other living organisms, in which they find nourishment, that is, food that suits them, here they hatch, grow and reproduce themselves.

Quoted in English in Paolo Mazzarello, The Hidden Structure: A Scientific Biography of Camillo Golgi (1999), trans. and ed. Henry A. Buchtel and Aldo Badiani