202 



♦ KNOWLKDGE ♦ 



[August 1, 1889. 



produce her sugar at home. This resulted in the com- 

 mencement of the beet sugar indu.stry, and thus amongst 

 the secondary results of war must be reckoned bounty-led 

 sugar. To judge of the economic aspects of the two 

 industries, many factors have to be taken into account. 

 "Wlien that has been done, this balance will be found dis- 

 tinctly in favour of the cane. Sugar-canes contain suth- 

 cient sugar to yield 70 to bO per cent, of their weight of 

 juice, in which there is some 20 per cent, of sugar. Beet- 

 roots, as an extended series of investigations have shown, 

 possess a percentage of sugar varying from 7 to a maximum 

 of under 14, and on the average about 11. Now an acre of 

 land which can be used for beet-growing will be rented 

 for, say, il. per annum, whilst in the colonies an equal area 

 of cane-producing land will be rented for about one-tenth of 

 that amount. Further, a great divergence is found in the 

 quantity of beet and cane which two equal areas can grow. 

 For instance, in the environs of Magdeburg, an acre will yieU 

 about 10 cwt. of sugar; whereas, in the home of the sugar- 

 cane, some 40-50 cwt. can be obtained. Then other items in 

 the ciist of production have to be considered; the differ- 

 ence in wages in the two regions, the difference in the cost 

 of fuel — in Europe where coal is necessary, in the colonies 

 where the waste matter of the cane supplies the whole, or 

 nearly the whole, of the fuel requii-ed. One can thus 

 realise the grounds on which the Brazilian Commission on 

 the sugar industry reported, that, in their opinion, " the 

 cost of production may be reduced in Brazil to such a 

 degree as to defy competition, and the struggle between 

 cane and beetroot must become ominous to the latter, 

 which thrives only by the artificial advantages which 

 European countries have devised." 



Hitherto the artificial advantages have been on the side 

 of the European countries; but now the greatly improved 

 means of transit, and the diflFusion of knowledge, are raising 

 the colonists to a position nearer equality in these respects, 

 of course excluding bounties. And by this time the 

 colonial sugar planter has learnt a severe lesson. He 

 understands that, whilst nature has showex'ed her gifts on 

 him with a lavish hand, she mercilessly punishes him for 

 carelessness and lack of promptitude. For if he cuts his 

 canes, they must within a few hours be crushed and ex- 

 tracted ; if he is negligent, and leaves them for only two 

 days, fermentation rapidly ensues under the conditions of 

 tropical temperature, and the canes turn sour and must be 

 thrown aside for fuel. In this way nature has fined men 

 whole fortunes. Great fortunes have been made in the 

 manufacture of sugar ; but of these processes, with their 

 special points of interest, an account must be reserved. 



EARTH-WORMS-II. 



By E. Mansel Sympson, M.A., M.B. Cantab. 



ET us look for a minute at the diagram, 

 which represents a section of the earth- 

 worm's body cut clean through the middle, 

 as it will give a clear idea of the relation 

 of parts inside the worm. On the outside, 

 all round, you see there is the skin (a in 

 the diagram) pierced in four places by 

 pairs of hairs (S) which have special 

 muscles at their inner ends to make them stand on end, as 

 indeed om- own haii-s have, but they are little used by 

 us save when we see a ghost, or think we do. Beneath 

 the skin come the circular bands of muscular fibre ; 

 withru those again are four bands of longitudinal muscle, 

 cut across. Then we come to a space — the body cavity, 



which you remember was formed by the hollowing out 

 of those masses of mesoblast. This communicates with 

 the outside world in each segment by a couple of coiled and 

 curved tubes, opening at one end into the cavity of one 



Fig. -1. — Transverse Section op Mature Earth-wobm. 



a, epidermis ; 0, circular muscles ; y, longitudinal muscles ; 8, hairs ; 



e, dor.sal blood-vessel ; f, " heart ; " tj, sub-intestinal blood-vessel ; 



9, sub-neural blood-vessel ; i, double nerve-cord ; k, Intestine, with 



dip (Typhlosole) from upper surface. 



segment, running through the partition-wall, and out 

 through the body-wall of the next segment. They are 

 plentifully supplied with blood, and serve as kidneys for the 

 animal. On the upper surface of the intestine you see the 

 dorsal blood-vessel, with the so-called heart leading down to 

 join the sub-intestinal vessel ; below the latter is the double 

 ner\^e-cord, and below that the sub-neural blood-vessel. 

 Then in the middle is the intestine cut across, with its 

 muscular coat and special lining membrane and that curious 

 dip from its upper surface. No special breathing-apparatus 

 is found, as worms breathe by their skin. The two sexes 

 are united in the same individual, but two individuals pair 

 together. As for senses, the earth-worms are rather badly 

 off. They have no eyes, and have been thought quite 

 insensilale to light. But Mr. Darwin found that when the 

 light was concentrated and long-enduring they certainly 

 showed some percejjtion of it. This, however, only occurred 

 when the light was allowed to fall especially on the 

 anterior end of the body ; consequently it probably affected 

 the ganglia above the pharynx by pa.ssing through the skin. 

 In the rest of the body you will remember the nerve-cord 

 and ganglia lie directly under the intestinal canal, and so 

 are more shielded from the action of light. Probably this 

 perception of light is quite enough — poor as it may seem — 

 to enable them to distinguish Ijetween day and night. 

 Somewhat in the same way as we go to sleep at night 

 twenty-four hours after twenty-four hours, so do the ejirth- 

 worms disappear- into theii- burrows at the dawn to re- 

 appear with the darkness of night. It seems to have 

 become an habitual action with them, incapable of 

 being changed with changed conditions, for a number of 

 worms kept by Mr. Darwin in pots covered by glass plates 

 with black paper spread carefully ovei', and placed before a 

 north-east window, behaved exactly as worms generally do — - 

 they came out at night and remained in their burrows 

 during the day. Earth-worms also are quite deficient in 

 the sense of hearing ; they will take no more notice of the 

 shi-Ul, ear-piercing note of a penny whistle than of the deepest 

 and loudest tones of a bassoon. But worms are wonderfully 

 sensitive to vibrations in solid matter ; when placed in pots 

 on a piano which was being plajed, one gentle note was 

 ijuite enough to send them back into their burrows, like a 

 rabbit to his hole. And a common way of catching worms 

 is to beat the ground with a spade, whereupon they come 

 out in numbers. All over its body is the worm sensitive to 

 contact. A slight puff of air will cause an instant retreat ; 

 but the most highly developed part in this respect is the 

 oral end, by moving which about it gains a general im- 



