178 



of the plains and around it grow 

 the only living trees to be seen for 

 miles. " 



This charming pen-picture will 

 give the reader a vivid and truthful 

 impression of this wonderful de- 

 posit which excites the unbounded 

 enthusiasm of every intelligent vis- 

 itor. 



The late World's Fair at Chi- 

 cago for the first time afforded the 

 public an adequate idea of the 

 beauty and diversity of this fossil- 

 ized wood. In the Arizona Build- 

 ing, and more extensively in the 

 Manufacturers' Building, were re- 

 markable exhibits of the material. 

 In the Manufacturers' Building, 

 the Drake Company, of St. Paul, 

 Minn., made a superb display of 

 the material sawn into slabs and 

 polished, to form table tops and 

 other pieces of furniture. The 

 beauty of these polished agate sur- 

 faces cannot be adequately de- 

 scribed, and they naturally attract- 

 ed the admiring attention of thous- 

 ands. 



The Drake Company, which has 

 made a special business of prepar- 

 ing the silicified wood for decorat- 

 ive purposes, has erected costly 

 machinery for sawing, shaping and 

 polishing the material at Sioux 

 Falls in South Dakote. There is 

 nothing in the whole range of na- 

 ture's mineral productions that ex- 

 ceeds these superb specimens in 

 beauty, if, indeed, there is any- 

 thing capable of being adapted for 

 similar purposes that can compare 

 with it. Extensive as the deposit 

 is, it contains comparative!)' little 

 material sufficiently perfect to be 

 adapted for the production of large 

 and flawless slabs, and the com- 

 paratively limited supply, to which 

 should be added the cost of work- 

 ing the material on account of its 

 extreme hardness, must always ren- 

 der it a costly luxury, but one 

 which must enhance in value with 

 years from its growing rarity, its 

 practical indestructibility and sur- 

 passing beauty. — In The Manufact- 

 urer and Builder. 



Earthworms. 



BY C. F. MARSHALL, M. D. , B. SC. , F. R. C. S. 



The common earthworm, despis- 

 ed by man and heedlessly trodden 

 under foot, fulfills a part in nature 

 that would seem incredible but for 

 the facts revealed by the patient 

 and long-continued researches of 

 Darwin. "Worms," says Darwin, 

 "have played a more important 

 part in the history of the world 



NATUBAL SCIENCE NEWS. 



than most persons would at first 

 suppose." Let us follow Darwin, 

 and see how this apparently insig- 

 nificant creature has changed the 

 face of nature. We will first con- 

 sider the habits and mode of life 

 of the earthworm. As every one 

 knows, the worms live in burrows 

 in the superficial layer of the 

 ground. They can live anywhere 

 in a layer of earth, provided it re- 

 tains moisture, dry air being fatal 

 to them. They can on the other 

 hand, exist submerged in water for 

 several months. They live chiefly 

 in the superficial mould less than a 

 foot below the surface, but in long- 

 continued dry weather and in very 

 cold seasons they may burrow to a 

 depth of eight feet. The burrows 

 are lined by a thin layer of earth, 

 voided by the worms, and end in 

 small chambers in which they can 

 turn round. 



The burrows are formed partly 

 by pushing away the earth, but 

 chiefly by the earth being swallow- 

 ed. Large quantities of earth are 

 swallowed by the worms for the 

 sake of the decomposing vegetable 

 matter contained in it, on which 

 they feed. The earth thus swal- 

 lowed is voided in spiral heaps, 

 forming the worm castings. In 

 this case the worm obtains food 

 and at the same time excavates its 

 burrows. 



In addition to the food thus ob- 

 tained, half decayed leaves are 

 dragged into the burrows, mainly 

 for food, but also to plug the mouths 

 of the burrows for the sake of pro- 

 tection. Worms are also fond of 

 meat, especially fat; they will also 

 eat the dead bodies of their rela- 

 tives. They are nocturnal in habit 

 remaining, as a rule, in the bur- 

 rows during the day and coming 

 out to feed at night. 



The leaves dragge d into the bur- 

 rows are moistioned by a fluid se- 

 creted by the worm, of a digestive 

 nature, and the foe d is thus partly 

 digested before be ing swallowed. 

 The digestive fluid of the earth- 

 worm resembles the pancreatic 

 juice of higher animals, and only 

 acts when alkaline. Various acids 

 are produced by decaying vegeta- 

 ble matter, and similar changes oc- 

 cur in the leaves swallowed by 

 worms. Now if some of this acid 

 was not neutralized, digestion .could 

 not take place, because the diges- 

 tive fluid is alkaline. This is avoid- 

 ed by the action of some small 

 glands, called the calciferous glands, 

 opening into the alimentary canal. 

 These glands secrete carbonate of 

 lime;, which neutralizes the acids 

 generated in the decaying leaves. 



The earth worm has no eyes, but 

 is affected by strong light, if ex- 

 posed to it for some time. It has 

 no sense of hearing, bwt is sensi- 

 tive to the vibrations ©I sound. 

 The whole body is sensitive to 

 touch. There appears to be some 

 sense of smell, but this is limited 

 to certain articles of food, which 

 are discovered by the worm when 

 buried in earth, in preference to 

 other bodies not relished. The 

 worm appears to have some degree 

 of intelligence from the way in 

 which it draws the leaves into its 

 burrows, always judging which is 

 the best end to draw them in by. 

 This is remarkable in so lowly or- 

 ganized an animal, being a degree 

 of intelligence not possessed by 

 many animals of complex organi- 

 zation. For instance, the ant can 

 often be seen dragging objects 

 along transversely, instead of tak- 

 ing the m the easiest way. 



As we have seen vast quantities 

 of earth are continually being pass- 

 ed through the bodies of worms 

 and voided on the surface as cast 

 ings. When it is stated that the 

 number of worms in an acre of or- 

 dinary land suitable for them to 

 live in is fifty-three thousand, we 

 can imagine the great effect which 

 they must have on the soil. They 

 are, in fact, continually plowing 

 the land. At one part of the ali- 

 mentary canal of the worm is a 

 gizzard, or hard muscular organ, 

 capable of grinding food into par- 

 ticles; it is this gizzard which is the 

 main factor in triturating the soil, 

 and it is aided by small stones 

 swallowed with the earth, which 

 act as mill stones. 



The earth is thus continually 

 passing through the mill formed by 

 the gizzards of worms, and is re- 

 duced to fine mould. Again, from 

 the collapsing of the old burrows 

 the mould is in constant slow 

 movement and its particles rubbed 

 together. Fresh surfaces are thus 

 exposed to the action of the car- 

 bonic acid in the soil and to the 

 humus acids, agents which act in 

 the destruction of stones and rocks. 

 Moreover, the acids produced in the 

 digestive tract of the worms are not 

 all neutralized, for the castings 

 have an acid reaction, and this acid 

 acts further in the disintegration 

 of rocks. 



Thus all the mould covering a 

 field passes every few hours through 

 the bodies of worms, and the frag- 

 ments are probably swallowed and 

 brought to the surface many times 

 over in the course of centuries. 

 Changes are also produced in the 

 slopes of hills by the flowing down 



