MOEPHOLOGY OF THE BAELEY GKAIK. 



25 



fig. 6.) Given the same area in contact wdtli the endosperm, the 

 epithelial layer composed of long cells ^^^ll have a much greater cubical 

 content. Also, if the cells be narrower, their total number mil be 

 o-reater in a given area. If Torrev's conclusion that the nucleus is 

 the final organ to which secretion is due is correct, this increase in the 

 number of cells and in the consequent number of nuclei is an actual 

 increase in secreting power. In any case, it is reasonable to assume 

 that a greater number of cells with a gTeater plasmic content is more 

 efficient tlian a smaller number of cells with a smaller plasmic content. 

 The existence of this type 

 of epithelial layer in the 

 most prized malting bar- 

 leys gives corroboration to 

 this belief. Tlie long, nar- 

 row cell prevails in the bet- 

 ter sorts, but becomes less 

 prominent as the cpiality 

 decreases. 



An iileal grahi of barley, 

 then, is one possessing a 

 relatively short longitudi- 

 nal and a correspondingly 

 long transverse diameter, 

 with both the distal and 

 proximal ends broadly oval. 

 It contains an embryo mth 

 a large scutellum reaching 

 over the edges of the endo- 

 sperm and an epithelial 

 layer composed of long, 

 narrow cells. 



U- f ■ , • f U 1 I'lo. 0. — I wo types of epilliulial layers:^!, An inferior epithelial 



nil (Tior gram 01 Oarley layor or short, l road cells; B, i;n ellicient epithelial layer of 



Ls elongated and Ls pointed '""?> narrow colk. (< amera lucida drawings of actual 



, , 1 Tx A. • specimens.) 



at both ends. It contains 



an ombr\'o with a narrow scutclliini the ('])il,liehal layer of wliich is 



made up of short, broad ctdls. 



A r.arlcy having the most })errect construction for the i)ro(luction of 

 cnzyrns may still fall short of its highest efficiency. TJic size and the 

 quality of the secreting surface' are tlie structural factors of potential 

 en(!rg}', but they are limited ]>}'■ a third element, namely, coiulitiou. 

 If they are not in the highest state of \ila,l cnci-gy, I heir iiiuxiiiiiini 

 efficiency will not he realized; and, fin-l hciinorc, this vital energy 

 must be in a (UTtain stat(! of activity nol cnlii-cly und(M'sl,o(»d and 

 difficult to dcfillf, whicll may he designated, \i)V \\;tlil of a, heller 

 tenii, as "potency." For example, iil. iJie (inieof I he inal iii'il \- of t Ik; 



