1876.] 
Notices of Books. 
103 
here remark that the difficulty of finding whether a given subjedt 
has been already investigated is greater in Natural History than 
perhaps in any other branch of science. Important observations 
in zoology and botany may be found, not merely in the majority 
of scientific and literary periodicals, but even in sporting and 
political organs. 
It must not, however, be supposed that Mr. Darwin’s sole 
merit in this matter consists in verifying previous researches and 
in presenting them in a form accessible to the English reader. 
He tells us, with perfecl: justice : — “ I believe that my observa- 
tions, founded on the examination of above a hundred widely 
distindt living species, contain sufficient novelty to justify me in 
publishing them.” 
Twining plants form, it appears, the largest subdivision of the 
climbers, and represent, according to Mr. Darwin, the primordial 
and simplest condition of the class. If a young hop-shoot be 
observed as it rises from the ground, the first two or three joints 
are straight, and remain stationary, like the shoot of a non- 
climbing tree. The next joint, however, when still quite young, 
bends to one side, and moves slowly round to all points of the 
compass, travelling with the sun. In hot weather, if the plant is 
in vigorous health, each revolution is completed in two hours 
and about eight minutes. As the plant grows up the older joints 
lose this property, but the three top joints always continue to 
rotate. If the shoot is left free it describes a circle of about 19 inches 
in diameter. Another twiner, the Ceropegia Gardnerii, revolves 
in a diredtion opposite to the sun, and describes a circle of 62 
inches in diameter. When one of these revolving shoots 
encounters a stick it twines round it in a spiral form. The thick- 
ness of the objedt found by a shoot is a very material point. The 
common nightshade (Solatium dulcamara ) can twine only around 
such stems as are at once thin and flexible. The only native 
English twiner which can clasp trees is the honeysuckle, which 
Mr. Darwin has found twining up a young beech tree 4^- inches 
in diameter. In a room lighted on one side Phaseolus multiflorus 
could not ascend posts of from 3 to 4 inches in diameter. In 
the open air it could twine round supports of this thickness, but 
failed ascending one of 9 inches. In South Brazil F. Muller 
saw a tree about 5 feet in circumference spirally ascended by a 
plant belonging to the Menispermaceas. Mr. Darwin very aptly 
remarks that in cold climates it would be “ injurious to the 
twining plants which die down every year if they were enabled 
to twine "round trunks of trees, for they could not grow tall 
enough in a single season to reach the summit and gain the 
light.” Twining plants with very long revolving shoots are not 
necessarily able to ascend thick supports, their great length and 
power of movement merely aiding them in finding a distant 
objedl up which to climb. The rate of revolution in all the 
plants observed by Mr. Darwin was merely the same by day as 
