i56 



HA RD Wl CKE 'S S CIENCE - G OSSIP. 



the worms, which had drawn them there for food. I 

 laid about a dozen of these dead willow-leaves on the 

 top of my flower-pot, and in a day or two they were 

 all drawn in (always with the stalk uppermost), and 

 so gradually devoured. I put in a fresh supply, and 

 one evening, on gently removing the cover, I detected 

 a worm with its head affixed, or stuck by the slime, 

 to one of the leaves. It did not stir in the least, and 

 seemed perplexed by the stalk of the leaf resting 

 against the side of the pot. But in the morning the 

 clever creature had turned it round, and there was the 

 stalk-end sticking up in the worm hole ! It had 

 turned it completely round, and whereas it had lain 

 like a bar across the hole, it had contrived to pull in 

 the narrow end. All this is evidently done by the 

 creature feeling the position of the leaf. But to turn 

 it when it is the wrong way is a process that resem- 

 bles a kind of low reasoning rather than mere instinct 

 — if, indeed, we have any right to regard the two 

 motives of action as essentially distinct.* 



Not only leaves were thus drawn in and devoured, 

 but grains of wheat, canary, and rape-seed, sprinkled 

 on the top of the earth in the flower-pot, were gra- 

 dually carried down, and soon entirely disappeared, 

 so that after a few days not a single seed was to be 

 seen. I tried bits of stick, bread-crumbs, scraps of 

 ginger-bread, and biscuit, but they were not much 

 noticed, though the sticks were generally moved. 

 After a few days, the seeds came up, thus affording a 

 pretty conclusive proof that one province or function 

 of the earth-worm is to promote the growth of plants 

 by burying seed which might otherwise perish, or be 

 picked up by birds. 



In the above purely popular account of the earth- 

 worm, no attempt has been made at a scientific descrip- 

 tion. 



The anatomy of the earth-worm, and the organs 

 and process of reproduction, which are extremely 

 curious, are very fully explained in an elaborate 

 paper by Sir Everard Home, Bart., in the " Philoso- 

 phical Transactions of the Royal Society" for 1S23, 

 part 1, pp. 140 — 151, illustrated by four plates, 

 xvi. — xix., containing magnifieddiagramsof the various 

 internal parts. f These are, to enumerate them briefly, 

 a head with a distinct mouth, having some serrated 

 apparatus, not very unlike teeth, a brain (cerebral 

 ganglia), spinal cord, artery, with six lateral lobes or 

 cells on each side, containing red blood, perhaps 

 equivalent to a series of hearts, an oesophagus, crop, 

 gizzard, intestinal canal, and anal aperture. The 

 creature is divided through its entire length into com- 

 partments, containing eggs enclosed in membranous 



* Sir Emerson Tennent, in his "Natural History of 

 Ceylon," p. 90, relates, as a singular instance of the sagacity of 

 an elephant, his turning sideways a log, which he was carrying 

 balanced across his tusks, so as more easily to make his way 

 through the trees. 



t See also Dr. Nicholson's " Manual of Zoology," p. 2oo> 

 ed. 3, and especially Prof. Huxley's " Manual of the Anatomy 

 of Invertebrated Animals," pp. 219 — 226. 



bags. Near the middle is a thick swollen ring * of 

 rather darker colour. This is connected with the 

 generative process, and appears to have given rise to 

 the popular opinion that a worm cut in two will ' 'mend 

 itself," or grow into two worms. The roughness 

 which is felt on handling a worm arises from minute 

 bristles which grow out of the rings, and doubtless 

 assist the creature in its movements. The slime 

 exuded is not nearly so tenacious as that of the snail 

 or the slug, but it probably facilitates the progress of 

 the worm through its labyrinthine home, and it ap- 

 pears to impart some solidity both to the walls of the 

 passages and to the substance of the excreta. 



THE DEVELOPMENT OF SPECIALLY 

 ADAPTIVE APPLIANCES IN PLANTS. 



THERE is perhaps no branch of scientific know- 

 ledge which has received greater stimulus of 

 late years than that part of physiological botany which 



Fig. 104. Flower showing 

 stamens in juxtaposition 

 with style in keeled lip 

 a (nat. size). 



Fig. 105. Flower showing the 

 deeply-cut petals (nat. size). 



Fig. 106. Flower showing the dropped keel a (nat. size). 



refers to the colours of flowers and the origin of their 

 forms. The observations of Drs. Darwin and Miiller, 

 of Sir John Lubbock, and others, have supplied 

 material for modern scientific thought to explain the 

 whole scheme of vegetable creation, and attempt is 

 now even being made by some to connect with the 

 development of vegetable life the colour sense of the 

 animal world, including that of man himself. 



A writer in Cornhill Magazine for May has 

 striven to show that all irregular-shaped flowers, 

 especially those which combine with colour attractive- 



* In a full-grown worm, a part of the body into which more 

 or fewer of the segments between the twenty-fourth and thirty- 

 sixth inclusively enter, is swollen, of a different colour from the 

 rest, provided with abundant cutaneous glands, and receives the 

 name of cingulum or clitellum. — Huxley, p. 221. 



