... courtyard behind theMeridian gate. See the second sentence ofparagraph 5.05 _TOEFL Reading,Ch4,105- 120 7/29/06, 12:02 119 06 _TOEFL Reading,Ch 4,121-134 7/29/06, 12:03122 ... Uni-versity of Michigan School of PublicHealth and became part of a group thatwas working to develop a vaccine againstinfluenza.In 194 7, Salk became associate profes-sor of bacteriology and ... American Medical Association. In 195 4, a mass field trial was held, and thevaccine, injected by needle, was found tosafely reduce the incidence of polio. OnApril 12, 195 5, the vaccinewas releasedfor...