Morphology of the barley grain with reference to its enzym-secreting areas . ong transverse diameter,with both the distal andproximal ends broadly contains an embryo witha large scutellum reachingover the edges of the endo-sperm and an epitheliallayer composed of long,narrow cells. An inferior grain of barleyis elongated and is pointedat both ends. It containsan embryo with a narrow scutellum the epithelial layer of which ismade up of short, broad cells. A barley having the most perfect construction for the production ofenzyms may still fall short of its highest efficiency. The size an
Morphology of the barley grain with reference to its enzym-secreting areas . ong transverse diameter,with both the distal andproximal ends broadly contains an embryo witha large scutellum reachingover the edges of the endo-sperm and an epitheliallayer composed of long,narrow cells. An inferior grain of barleyis elongated and is pointedat both ends. It containsan embryo with a narrow scutellum the epithelial layer of which ismade up of short, broad cells. A barley having the most perfect construction for the production ofenzyms may still fall short of its highest efficiency. The size and thequality of the secreting surface are the structural factors of potentialenergy, but they are limited by a third element, namely, they are not in the highest state of vital energy, their maximumefficiency will not be realized; and, furthermore, this vital energymust be in a certain state of activity not entirely understood anddifficult to define, which may be designated, for want of a betterterm, as potency. For example, at the time of the maturity of the. Fig. 6.—Two types of epithelial layers: A, An inferior epitheliallayer of short, 1:road cells; B, an ellicient epithelial layer oflong, narrow cells. (Camera lucida drawings of actualspecimens.) 26 BULLETIN 183, U. S. DEPARTMENT OF AGRICULTURE. grain the protoplasm of the cells of the embryo is active and possessedof all the vitality of newly formed tissue, yet barley germinates veryimperfectly at this time. The epithelial layer will attack the endo-sperm, even under the most favorable conditions of moisture, tem-perature, etc., only in a weak, erratic manner. The cells do not seemready to exert their full force. In fact, it is only after a certainperiod of rest that the grain displays its full germinative potency and becomes thoroughly re-teponsive to germinativeinfluences. It has been noticedthat the sweatingprocess in the curing ofbarley is closely con-nected with this changein the internal energy ofthe
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