ABSTRACT
The plaque assay, an indispensable tool for the study of bacteriophage, was described in the earliest publications on the discovery of these viruses. Felix d'Hérelle, credited as co-discoverer of phage (along with Frederick Twort) described, in effect, the first plaque assay in 1917 [1], when he wrote the following:
…if one adds to a culture of Shiga as little as a millionfold dilution of a previously lysed culture and if one spreads a droplet of this mixture on an agar slant, then one obtains after incubation a lawn of dysentery bacilli containing a certain number of circular areas of 1 mm diameter where there is no bacterial growth; these points cannot represent but colonies of the antagonistic microbes: a chemical substance cannot concentrate itself over definite points.” (Translation from Stent [2].) The “antagonistic microbes” were then named “bacteriophage.”
