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THE POPULAR SCIENCE MONTHLY. 



amine the under surface with the micro- 

 scope after the separation of the cuticle, 

 the peculiar and characteristic space be- 

 tween the two cells of the stomata is readi- 

 ly perceived. The long unicellular hairs 

 of the tea-leaf are also peculiar. The em- 

 ployment of caustic potash is desirable in 

 observing these characters. 



" In the she-leaf the serratures are direct 

 incisions, numerous, often irregular, and ex- 

 tending down to the base. There are no 

 spines. The hairs are shorter and coarser 

 than those of the tea-leaf, and are marked 

 in a peculiar manner. The elder-leaf is more 

 pointed than that of the tea-plant, and the 

 lobes are unequal at the base. The serra- 

 tures are direct incisions. The midriff has 

 hairs on it, and on the leaf itself there are 

 several kinds of hairs, notably a short, spin- 

 ous, striated hair, which occurs on the up- 

 per surface. The serratures of the willow- 

 leaf much resemble those of tea, but the 

 cell-walls of both the upper and under 

 epidermis differ from those of the tea leaf 

 in not being sinuous, and there are long, 

 coarse, striated hairs. When perfect, the 

 elongated form of the willow-leaf sufficient- 

 ly distinguishes it from tea, and the vena- 

 tion is also entirely different. The chief 

 foreign leaves added by the Chinese are 

 those of Chloranihus inconspieuus and of 

 Camellia sasanqua, the latter of which pre- 

 sents a close resemblance to the tea plant." 



Csefnlness of the Robin. Pitying the 

 ignorance of farmers, and country-people 

 generally, touching the habits and useful- 

 ness of the robin, and pitying equally the 

 poor bird itself for the abuse which this 

 ignorance brings upon it, Caroline Bryce, 

 in the April Naturalist, has rendered a ser- 

 vice to both by pointing out in a very in- 

 teresting way the value of the bird to the 

 country, and the mistake that is made in 

 attempting to drive it from our fields and 

 groves. "The robin has two broods in a 

 season, each brood varying in number from 

 two to five. The young are fed exclusively 

 on insects, and their rapid growth and 

 consequent voracity, only equaled by the 

 larvae stage of insect-life, makes an abun- 

 dant supply of insect-food an indispensable 

 requirement. The food of the mother-bird 

 is also chiefly insects, and this double de- 



mand makes the robin a valuable assistant 

 to the farmer and horticulturist in keeping 

 under insect pests. Regarding its sup- 

 posed habit of cherry-eating, the author 

 is of opinion that it is attracted chiefly by 

 the color of the fruit, and not by any spe- 

 cial liking for it as food ; that it picks the 

 cherries for the same reason that it picks 

 to pieces a red flower. Instead of being 

 an enemy to the cherry-crop, it is in reality 

 a most important aid in securing an abun- 

 dant supply of healthy fruit. If I should 

 venture to say that not a cherry would 

 grow, fit to be eaten, were it net for the 

 birds, the bare idea would be hooted as 

 preposterous, yet such, nevertheless, is my 

 belief. Were it possible to remove all the 

 birds out of the way, for one season at 

 least, what a decided difference would our 

 future orchards present ! Where now are 

 thrifty growths, beautiful leafage, and large 

 crops of fair fruit, would be seen stinted, 

 moss-grown limbs, with sparse or meagre 

 foliage, crops of dwarfed specimens, that 

 have finished their growing, in a knotty, 

 wormy, inferior state. The majority of all 

 the large families of insects are bred in the 

 earth, and go through various forms in dif- 

 ferent stages of existence, and are devoured 

 by birds of every description, chief among 

 which stands our friend the robin." 



How Leaves are blanched by Bright 

 Sunlight. The leaves of certain plants 

 grow pale in the full glare of the sun, and 

 it becomes a question whether this change 

 is due to a diminution of the amount of 

 chlorophyll. Mr. H. C. Sorby has repeat- 

 edly analyzed the leaves of such plants, 

 but the result showed that sunlight or shade 

 makes no difference in the quantity of the 

 chlorophyll. He therefore came to the 

 conclusion that the change in color is due 

 to some mechanical alteration in the struct- 

 ure of the leaves. This conclusion is con- 

 firmed by the independent researches of a 

 French observer, Prillieux. According to 

 the latter, exposure to bright light causes 

 both granular and amorphous chlorophyll 

 to collect together at the sides of the cells, 

 instead of being more evenly distributed. 

 The result is, that a much larger relative 

 quantity of white light is reflected, and the 

 leaves appear of a paler and whiter green. 



