For the first time in history, synthetic production of the fundamental “building block” of cellulose - the stuff that wood, cotton and other useful substances are made of - has been accomplished by research workers of the U. S. Public Health Service. When cellulose was first analyzed years ago it broke down into molecules of common glucose which were later found to be united in pairs to make double-sized molecules of a more complex sugar named cellobiose, now made artificially for the first time. The discovery is expected to aid in the manufacture of explosives, rayon, plastics and transparent wrappings.