In a preceding article by Eugene Pacsu2 he suggests that the exceptional character of the rotations of the a-and b-forms of substances having the pyranoid ring structure in the mannose series may be due to a difference in the conformation of the atoms forming the ring. I thank Dr. Pacsu, with whom I have conferred often during the progress of his research, for this opportunity to publish concurrently thc reasons which have led me to take the ...
