An initial linear relationship between increases in reciprocal specific viscosity and in reducing group liberation has been confirmed for that aspect of /?-glucosanase activity which involves attack on /3-glucosan only at points remote from the ends of molecules, i.e., endo-/?-glucosanase activity; excess reducing groups over and above those calculated from this relation are ascribed to exo-/?-glucosanase and cellobiase, Prolonged endo-action gives progressive degradation of large molecules with ulti mate production of cellobiose and laminarlbiose; exo-action gives celloblose from the start. The presence of cellobiase makes glucose production inevitable. Different raw cereals show different proportions of endo-and exo-activity and of cellobiase, but barley is moderately rich in all three. During the malting of barley, endoactivity is enhanced 100-200 fold, and there is a measure of resistance to heat inactivation on the kiln. Available evidence suggests that the increase in exo-activity is only moderate, and this activity may be entirely suppressed by kilning. Cellobiase activity is variable, but has been found in all extracts and preparations examined.Methods for differential inactivation of endo-and exo-enzymes have been examined, but only the latter can be readily destroyed. Vol. 62, 1056] PREECE AND HOGGAN: /J-GLUCOSANASE SYSTEM OF CEREALS 487

Of the two glucodisaccharides, four trisaccharides and eight tetrasaccharides which might be expected to arise by degradation of β‐linked glucose polymer containing irregular arrangements of 1.3‐ and 1.4‐linkages, evidence is presented which suggests that all but one of the tetrasaccharides have been obtained, by enzymic or acidic degradation, from β‐glucans isolated from barley or oats. Enzymic degradation—whether by endo‐β‐glucanase or exo‐β‐glucanase, and whether from the barley or the oat product—gives broadly the same qualitative pattern of oligosaccharide production, though there are minor differences. Oligosaccharides containing only one type of linkage are accompanied by others with mixed linkages, and description is given of the tentative characterization of the various products by a combination of chromatographic and electrophoretic techniques. The molecular constitution of the two glucans cannot be accounted for on the basis of regular alternation of small numbers of the two types of linkage.

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Attempts have been made to relate the properties of 89 samples of malt to the total nitrogen content of the barley and the modification of this nitrogen. The significance of different concentrations of malt permanently‐soluble nitrogen and wort nitrogen as yeast‐feeding and potential haze‐forming material is discussed. A modified extract‐prediction equation involving nitrogen and 1,000‐corn weight is given, as is also an alternative equation which does not involve 1,000‐corn weight and which Is preferred. The opportunity is taken to stress the importance of the fine‐coarse extract difference as a guide to modification. The results of hand valuation assessment of Proctor barley must be confirmed by nitrogen determinations.