Seilliere1 and Billard2 and others demonstrated the presence of cellulase in Helix pomatia by estimating the amount of glucose produced after action of the cellulase upon suitable substrates. Boynton and Miller3 showed saccharification of wood by extracts from the ship-worm, Bankia setacea. Trager4 found a cellulase from symbiotic intestinal flagellates of termites. He estimated the amount of glucose produced, both qualitatively (by means of Benedict's reagent) and quantitatively, after action of the enzyme upon filter paper which was dissolved and precipitated.We also made use of the fact that reducing substances (carbohydrates) were produced, as proof for the presence of slug cellulase. Two substrates were employed: (1) A finely divided suspension of cellulose was prepared by dissolving 1 gm. of Whatman's No. 40 filter paper in 100 cc. of Cross and Bevan's ZnCl2-HCl reagent. This solution was filtered by suction through cotton and poured into about 800 cc. of distilled water. The resulting precipitate w...