those that are harmful (T1 sensitivity in this case). This experiment dealt a blow to Lamarckian inheritance and set the stage for tremendous advances in genetics and molecular biology, launching a tsunami of research that eventually led to the discovery of DNA as the hereditary material and to cracking the genetic code. Of course, by then Avery, along with McCloud (and earlier, McCarty) was well on the way to showing the genetic capability of DNA.

In 1945, Delbrück, Luria, and Hershey set up a