STRUCTURE, MORPHOLOGY, AND PHYSIOLOGY. 27 



drops, aud still finer proteid granules are imbedded in 

 the very delicate protoplasmic net. They are often 

 called, but not properly, gluten cells : true gluten is not 

 to be found in a dry kernel ; it is first formed from one 

 of the albuminoids (Myosin) by the addition of water. 



Fio. 8. — Avena sativa L. I, Cross-section of the entire fruit. II, A small piece of 

 the peripheral portion, 1; 2, Pericarp; 3, Testa; 4, Remains of the nucellus; 5-7, 

 Amylaceous tissue; 5, Gluten cells; 6 and 7, Cells of albumen containing com- 

 pound starch-grains — at 7 they are richer in albumen and poor in starch; 8, Fibro- 

 vascular bundle of the seed-coat. (From Harz, "Landwirtsch. Samenkunde.") 



Frequently we understand by gluten the whole of the 

 albuminoids, but these, as already shown, are not found 

 in the glutinous cells only. It has been often asserted 

 that bran and bran-bread (in which the glutinous layer 



