ARRANGEMENTS COMMON TO CRYSTALS, PLANTS, ANIMALS 7 



PLATE IV 



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This plate shows how certain crystals formed in viscous fluids present a radiating, concentric arrangement ; 

 how other crystals display pentagonal and hexagonal shapes ; how protagon develops spiral forms ; how molecules 

 tend to aggregate and form cells with nuclei ; how plants and animals display various markings which result in 

 radiating or concentric arrangements or both ; how plants and animals exhibit for the most part some kind of 

 division or segmentation by which they can build themselves up and divide and separate part of their substance 

 in the process of reproduction. Lastly, how growth and pressure in constricted areas modify form. 



FiQ. 1. — Precipitation of carbonate of calcium from a viscous solution on a .slide of glass, showing molecular, nuclear, and cell forms 

 in various stages of development, a, Oval body containing nucleus ; b, round body containing nucleus ; c, globular crystals of 

 carbonate of lime, showing concentric and radiating arrangements (J. H. Bennett). 



Fig. 2. — A perfectly formed globular crystal of carbonate of calcium with concentric and radiating lines (J. H. Bennett). The 

 concentric and radiating arrangements so well seen here are fretjuently met with in the transverse sections of the stems of plants and 

 of bones and other tissues of animals, as shown more especially in Plate v., p. 9 ; and in Plates Ixii. and Ixiii., pp. 156 and 158. 



Fig. 3. — Flattened ery.9tals of carbonate of calcium adhering at their edges, on the surface of lime water, resembling epithelium in 

 form (Fig. 4). The crystals are pentagonal in shape, and resemble the pentagonal and hexagonal liver cells (Fig. 12), and the 

 pigment cells of the choroid coat of the eye (Fig. 13). Compare with hexagonal cells of honeycomb; also with transverse sections 

 of basaltic columns of Staffa in Scotland, and the Giant's Causeway in Ireland (Plate xl., Figs. 1 and 2, p. 63) (the Author). 



jPiG, 4. — Pavement epithelium from human skin, showing pentagonal and hexagonal forms, chiefly the latter. Compare with 

 Figs. 3, 12, and 13 (the Author). 



Fig. 5. Shows straight, curved and spiral processes shooting out from a mass of protagon on the addition of water, artificial 



formation (J. H. Bennett). The spiral is a fundamental formation in nature (the Author). 



Fig. 6. Concentric layers occasionally formed at the extremities of free ends of the protagon (J. H. Bennett). 



Pig, 7. This figure comes under Fig. 1. Shows cry.stal]ine forms assuming the cell shape, ii, Crystalline forms; ft, angles 



of crystals rounded off; c, ovoid cell forms ; d, cell forms aggregated together (J. H. Bennett). 



Fig. 8.— Various arrangements of molecules, a, Finely molecular mass ; b, molecules varying in size as seen in milk ; r, molecules 

 aggregated in groups ; d, histolitic molecules from broken-down fibrous tissue (J. H. Bennett). 



Figs. 9 and 10. Fatty molecules precipitated from an alcoholic solution arranging themselves to resemble cells with a nucleus 



(a, b) and nucleoli (c) (J. H. Bennett). 



Fig. 11. Spinous cells from the Malpighian layer of the human epidermis (after hchultze). Show concentric and radiating 



arrangements with a certain amount of angularity. 



