The field of the Chemistry of Starch is so wide and the complexities involved are so great that any attempt to solve the problems of the constitution of starch cannot be spread over the whole front, but must necessarily be confined to a few chosen points of attack. The following introduction, therefore, is not presented as a complete survey of literature of the subject but merely as a resumé of those parts bearing immediately on the topics studies, with special reference to the work of Dr. J. K. Rutherford, inasmuch as the present thesis is a continuation and amplification of her work.