The construction of the second floor addition was completed in 1961 with the receipt of a $70,000 grant from the NIH. Interestingly, the designers of the original concrete building in 1929 had looked to the future and made provisions to accommodate a second floor if it became necessary. In the newly renovated laboratory the first floor was transformed into a Drosophila genetics laboratory and the new second floor housed bacterial genetics and biochemistry laboratories. The addition was designed by George B. Post & Sons and featured a vertical board exterior sheathing motif.