There is a great deal of material on yellow fever and other tropical and infectious diseases. The majority of these publications are from the late nineteenth century and early twentieth centry (prior to WWI). These collections are not generally available in the online catalog, but must be accessed by using the old card catalog. Several classifications are used for the historic materials including the Dewey Decimal Classification and an early version of the NLM Classification system developed by Mary Louise Marshall, called "Reclassed." These collections are housed in the top level of the stacks. Books published prior to 1914 do not circulate without special permission. Materials in fragile condition may not circulate nor be photocopied. Please consult with the Matas Librarians.