948 FOODS AND FOOD ADULTERANTS. 



of cells, known as " Mitsclierlich bodies." They are now considered to 

 be epidermal hairs, but it is not decided as to whether they belong to 

 the membrane j ust described or to the surface of the cotyledon. Neither 

 the settlement of this question nor the membrane and hairs, are of any 

 great importance for our purpose, since both of these structures are 

 very rarely met in recognizable form in the commercial preparations. 



After the removal of the husk and the membrane just described, the 

 two fleshy, much-folded cotyledons, or seed leaves, remain, inclosing 

 the radicle (the embryo stem of the undeveloped plant) at the larger 

 end of the bean in a manner not a little suggestive of the retracted 

 head of a turtle. Examination of a thin section shows the cotyledon to 

 be made up of comparatively thin-walled, closely packed, polygonal 

 cells (see Plate XL.VII). The most of these cells are filled with starch 

 grains, fat, and albuminous material; isolated or small groups of cells 

 are homogeneously filled with the reddish brown to violet pigment, 

 cocoa red. Fiber bundles with spiral cells, similar to those of the husk, 

 occur in the veins. 



The starch grains are spherical, or nearly so, have a very indistinct 

 nucleus, react only feebly with polarized light, rapidly lose the blue 

 coloration imparted by iodine, and show only a slight tendency to 

 unite in the form of compound grains; three or four is usually the 

 maximum number so united. The size of the grains of cocoa starch is 

 usually stated to be 0.003-0.010 mm. The following measurements 

 were made in this laboratory : 



Measurements of starch (/rains from a sample of unprepared cocoa beans. 



Millimeters. 



5 grains measured ............................................. 0. 003 



11 grains measured ..................................... ........ 0. 004 



14 grains measured ............................................. 0. 005 



6 grains measured ............................................. 0. 006 



11 grains measured ............................................. 0. 007 



2 grains measured ............................................. 0. 008 



1 grain measured .............................................. 0. 009 



1 grain measured .............................................. 0.010 



51 Average of 51 grains ................................... 0. 0054 



Measurements of starch grains from Waltei 1 Baker <f Go's. "o-ackwl cocoa." 



Millimeters. 



3 grains measured ................................ ~ ............ 0. 002 



9 grains measured ............................................. 0. 003 



12 grains measured ............................................. 0. 004 



14 grains measured ................................. ........... 0. 005 



14 grains measured ............................................. 0. 006 



28 grains measured ............................................. 0. 007 



7 grains measured ............................................. 0. 008 



3 grains measured ............................................. 0. 009 



8 grains measured ............................................. 0. 010 



2 grains measured ............................................. 0. 012 



100 Average of 100 grains .................................. 0.0062 



