Data have been presented relating to the growth of 11 species of microorganisms isolated from deteriorated cotton fabrics on various derivatives of glucose, mannose, cellobiose, and cellulose. A high degree of specificity was exhibited. As long as there was at least one firmly bound substituent in every anhydroglucose unit, the resulting derivative was not susceptible to microbiological attack. Under such conditions the nature of the substituent has relatively little influence on the degree of resistance imparted. This was considered to be promising theoretical support for the underlying premise on which the idea of multipurpose topochemical reactions as a means of mildewproofing cotton fabrics was proposed.