42 



HUTCHINSON'S POPULAR BOTANY 



leaves assume a pallid hue until the sun appears, when, within the short 

 period of six hours of a clear sky and bright sunshine, their colour is changed 

 to a beautiful green. Mr. Ellis, an American writer, tells of a forest in one 

 of the northern States, the leaves of which, though fully expanded, were 

 almost white, no sun having shone upon the forest for twenty days. One 

 forenoon, however, the sun began to shine in full brightness, and the colour 

 of the forest absolutely changed so fast that the progress of the transforma- 

 tion could be watched. " By the middle of the afternoon the whole of this 

 extensive forest, many miles in length, presented its usual summer dress." 



Often associated with chlorophyll is starch (C 6 H 10 5 ), which plays so 

 important a part in the nutrition of mankind. " Starch makes the man," 

 said a lady lecturer half a century ago ; but she spoke of it in another 

 connection namely, as the stiffening property in linen articles of male 



attire. Starch was imported into this country 

 in considerable quantities during the sixteenth 

 and seventeenth centuries, when the enormous 

 ruffs inseparably connected with the Elizabethan 

 and early Stuart periods were in vogue. Gerarde 

 tells us that the best of this starch was obtained 

 from the Cuckoo-pint or Wake-robin (Arum 

 maculatum). " The most pure and white starch 

 is made of the roots of the Cuckoo-pint, but 

 most hurtful for the hands of the laundress 

 tliat k atn tlie handling of it ; for it choppeth, 

 blistereth, and maketh the hands rough and 

 rugged, and withal smarting." That dealer in 

 spells and philters, the notorious Mrs. Turner, 

 has the credit of introducing yellow-starched 

 ruffs into Britain, blue and white being the 

 fashionable colours hitherto. Mrs. Turner literally died in starch. In the 

 presence of many women of fashion she " made her exit on the scaffold at 

 Tyburn, rouged and dressed as if for a ball, and wearing an enormous ruff 

 stiffened with her own yellow starch." 



The formation of starch is effected by protoplasmic bodies, which may 

 either be the chloroplasts already spoken of or leukoplasts (Greek leukos, 

 white, and plasma, something formed), which only differ from the former 

 in being colourless. Starch-making chloroplasts are found chiefly in the 

 leaves of plants; leukoplasts in the roots and tubers and certain other 

 parts which are hidden from the light : yet the relationship between the two 

 is shown by the fact that leukoplasts turn green when light is admitted to 

 them for a sufficient time. They take a yellow or yellowish brown stain 

 when treated with iodine, and should be examined under a high power. The 

 starch-grains have the same chemical composition as cellulose (C 6 H 10 6 ), but, 

 unlike cellulose, are soluble in, water, and will take a blue or violet stain if 



FIG. 65. STAKCH- GRAINS IN 

 BROKEN CELLS OF A POTATO. 



