20 



elongated, but seldom distinctly cleft. With polarized light, 

 beautiful distinct crosses are shown and with the selenite plate 

 a brilliant play of colors is displayed. 



In case the hulls alone are used in the feeds, starch grains 

 may not occur and their presence may be detected by the 

 appearance of the seed coats under the microscope. The size 

 and appearance of the palisade cells (Fig. 11) and the column 

 cells of the spermoderm are the best means of diagnosis. The 

 palisade cells are from 60 — lOO^u in length and have a "light line" 

 immediately under the cuticle. They also have a lumen or cell 

 cavity of irregular shape. The column cells which constitute the 

 layer next below the palisade layer are shaped like an hour glass 

 or "figure 8", and are in the pea never more than 20fx in length. 

 This layer of column cells is only one cell thick. These cells are 

 easily isolated by heating and macerating with dilute alkali, and 

 they do not contain crystals, a distinction from the column cells 

 of other leguminous seeds. 



BEAN. 



{Phaseolus vulgaris, Metz.) 



There are several varieties of beans used as food by man, and 

 some of these are occasionally found in commercial stock feeds. 

 These are never found whole, but are either ground coarsely or 

 simply the hulls are used. The whole bean is more or less kidney 

 shaped, and longer than it is broad, although the different var- 

 ieties vary greatly in their measurements and the color also varies 

 greatly, white, brown, red, spotted and black being found. 



When the common ground bean is present the starch grains 

 are sufficient for its identification. These are large ellipsoidal, 

 kidney shaped grains from 16 — 60^ in length, with the laminae 

 distinct, hilum elongated and conspicuously cleft; with polarized 

 light, brilliant, distinct crosses are seen and with the selenite 

 plate a fine play of colors is obtained. 



In the absence of starch grains elements of the spermoderm 

 are sufficient for identification. The palisade cells are elongated, 

 (rarely over 60/i long,) narrow and have a "light line" immedi- 

 ately under the cuticle. This light line is characteristic of most 

 of the leguminous seeds, and each cell has a lumen, or cell cavity, 



