310 



The Microscope. 



The seed is covered with a thick skin or envelope, which is made 

 up of a set of beautiful prismatic crystal -like shapes of cellulose, 

 placed side by side longitudinally, so that these ends make the out- 

 side and inside surfaces of the skin or envelope, and appear very 

 much like the tops of the Giants' Causeway crystals of trap-rock. 



(See Fig. 1.) The group to the right shows three or four rows 

 of these cellulose bodies. They are displaced by the pressure of the 

 cover and slide, and appear to be end to end. In the middle of each 

 prism is an hour-glass contraction, which is in the central axis and 

 is sun-ounded with clear cellulose, which fills out the contour. To 

 the left, two groups of the face of the outer bean-membrane are 

 seen, showing the prism ends in contact. The crystal-elements of 

 the membrane are quite insoluble, polarize light, and resist the 

 digestive influences of the alimentary canal. They are found in 

 large quantities in the excrement of bean-eaters, and furnish a sure 

 proof, when found, that beans or peas enter into the diet of the 

 case under examination. 



The epithelia of the Lima bean are seen in Fig. 2, left group. 

 When interlocked, unsoftened and unseparated by cooking, they 

 must hold together the parts, over which they are spread, with great 

 firmness. 



The substance of the bean is made up of starch grains, con- 

 nective tissue, spiral vascular tissue, etc. The starch is not peculiar 

 in its appearance and is readily recognized. In a section of an 

 uncooked bean the starch''grains appear in globular masses of vary- 



