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SCIENTIFIC SIDE-LIGHTS 



532 



2624. PLASTICITY CHARACTERIZES 



LIFE The Crystal Changeless The Plant Im- 

 mobile The Animal Free The Soul More 

 Mobile Still. Now plasticity is not only a 

 marked characteristic of all forms of life, 

 but in a special sense of the highest forms. 

 It increases steadily as we rise in the scale. 

 The inorganic world, to begin with, is rigid. 

 A crystal of silica dissolved and redissolved 

 a thousand times will never assume any 

 other form than the hexagonal. The plant 

 next, tho plastic in its elements, is com- 

 paratively insusceptible of change. The very 

 fixity of its sphere, the imprisonment for 

 life in a single spot of earth, is the symbol 

 of a certain degradation. The animal in all 

 its parts is mobile, sensitive, free; the high- 

 est animal, man, is the most mobile, the 

 most at leisure from routine, the most 

 impressionable, the most open for change. 

 And when we reach the mind and soul this 

 mobility is found in its most developed 

 form. Whether we regard its susceptibility 

 to impressions, its lightning-like response 

 even to influences the most impalpable and 

 subtle, its power of instantaneous adjust- 

 ment, or whether we regard the delicacy and 

 variety of its moods or its vast powers of 

 growth, we are forced to recognize in this 

 the most perfect capacity for change. This 

 marvelous plasticity of mind contains at 

 once the possibility and prophecy of its 

 transformation. DRUMMOND Natural Law 

 in the Spiritual World, essay 8, p. 269. (H. 

 Al.) 



2625. PLATES, THIN, COLORS OF 



Illustrated by Colored Films on Molten Lead. 

 " We took a quantity of clean lead and 

 melted it with a strong fire, and then im- 

 mediately pouring it out into a clean vessel 

 of convenient shape and matter (we used 

 one of iron, that the great and sudden heat 

 might not injure it), and then carefully 

 and nimbly taking off the scum that floated 

 on the top we perceived, as we expected, the 

 smooth and glossy surface of the melted 

 matter to be adorned with a very glorious 

 color, which being as transitory as delight- 

 ful did almost immediately give place to 

 another vivid color, and that was as quickly 

 succeeded by a third, and this, as it were, 

 chased away by a fourth; and so these won- 

 derfully vivid colors successively appeared 

 and vanished till the metal, ceasing to be hot 

 enough to hold any longer this pleasing 

 spectacle, the colors that chanced to adorn 

 the surface when the lead thus began to cool 

 remained upon it, but were so superficial 

 that how little soever we scraped off the sur- 

 face of the lead we did, in such places, 

 scrape off all the color." [See FILMS; 

 COLORS; LIGHT, DOUBLE REFLECTION OF.] 

 BOYLE Experimental History of Colors, quo- 

 ted by TYNDALL in Lectures on Light, lect. 

 2, p. 68. (A., 1898.) 



2626. PLAY AN INDICATION OF IN- 

 TELLIGENCE Over against the countless 

 varieties of the play of children, reflecting 



all conceivable relations of life, stands the 

 single form of mock fighting among the 

 animals. ( Trained animals do not, of course, 

 concern us; their performances are not real 

 play.) Dogs, cats, and monkeys, even when 

 they are playing with their young, show 

 their affection by pretending to fight with 

 them. And tho it is true that play is an 

 indication of high mental development, and 

 brings the animal nearer to ourselves than 

 any other activity, it is rather the fact that 

 it plays than the nature of the play itself 

 which is the important point. . . . Ani- 

 mal play never shows any inventiveness, 

 any regular and orderly working out of 

 some general idea. WUNDT PsycholoQy, lect. 

 24, p. 358. (Son. & Co., 1896.) 



2627. PLAY AS AN ART OF PLEAS- 

 URE Sports of Children Imitative. Play is 

 one of the arts of pleasure. It is doing for 

 the sake of doing, not for what is done. 

 One class of games is spontaneous every- 

 where, the sports in which children imitate 

 the life they will afterwards have to act 

 in earnest. Eskimo children play at build- 

 ing snow-huts, and their mothers provide 

 them with a tiny oil-lamp with a bit of wick 

 to set burning inside. Among the savages 

 whose custom it is to carry off their wives 

 by force from neighboring tribes, the chil- 

 dren play at the game of wife-catching, just 

 as, with us, children play at weddings with 

 a clergyman and bridesmaids. All through 

 civilization toy weapons and implements 

 furnish children at once play and education ; 

 the North-American warrior made his boy 

 a little bow and arrow as soon as he could 

 draw it, and the young South Sea Islander 

 learned by throwing a reed at a rolling ring 

 how in after-life to hurl his spear. It is 

 curious to see that when growing civiliza- 

 tion has cast aside the practical use of some 

 ancient contrivance it may still survive as 

 a toy, as where Swiss children to this day 

 play at making fire by the Old- World plan 

 of drilling one piece of wood into another; 

 and in our country lanes the children play 

 with bows and arrows and slings, the seri- 

 ous weapons of their forefathers. TYLOR 

 Anthropology, ch. 12, p. 305. (A., 1899.) 



2628. PLAY OF YOUNG ANIMALS 

 AND OF CHILDREN The play of man and 

 the animals differs in the same way as their 

 " intelligence." We regard certain actions 

 of the higher animals as playful when they 

 take the form of imitations of purposive 

 voluntary actions. We know that they are 

 imitations because the end pursued is only a 

 fictitious end the real end being excitation 

 of joyous emotions similar to those which 

 follow as secondary effects from genuine 

 purposive action. That means, you see, that 

 the play of animals is, for all practical pur- 

 poses, identical with play among mankind. 

 Our own play, at least in its simpler forms 

 e. g., in the play of children is merely an 

 imitation of the actions of every-day life 



