Technological and industrial history of 20th-century Canada Blood tests would become increasingly sophisticated in the coming years. The electroencephalograph, used for the diagnosis of neurological disorders was introduced in major Canadian medical institutions in the late forties. The techniques for the mass production and distribution of vaccines and for the mass public inoculation were introduced during these years. Polio was a disease that affected large numbers of Canadian children during the first part of the 20th century. In the US, research by Dr. Jonas Salk in the late 1940s led to the discovery of vaccine for the prevention of this disease. However, there was no technique for
Salk School of Science Perry and the vice/ assistant principal is Jennifer Goodwin. The school allows students to bring money to school and at lunch time, to go out and buy themselves lunch at a variety of delis and restaurants. The school shares its building with another school, P.S. 40 which owns most of the building. There is a gymnasium, a cafeteria which is shared between the schools, and 2 floors exclusive to Salk School of Science. Both are located near the top of the building. There are 3 entrances one to the left side of the building, one to the right and one