February, 1931 



EVOLUTION 



Page seventeen 



The Amateur Scientist 



A Monthly feature conducted by Allan Broms 



NATURE'S HUMBLE PLOWMEN 



A CCORDING to an 



official report, 

 one great damage done by the 

 Mississippi flood was drowning the earth- 

 worms throughout the inundated area. 

 This does not indicate a wave of official 

 compassion for earthworm feelings, nor 

 even concern over wholesale loss of good 

 fishing bait, but merely that earthworms 

 have come to be recognized as an eco- 

 nomic necessity in that they act as Na- 

 ture's lowly plowmen who loosen, pulver- 

 ize, moisten and otherwise transform our 

 soils to greater fertility. 



Charles Darwin was first in realizing 

 their soil-forming function and the vast- 

 ness of their gardening operations. His 

 studies extended over more than forty 

 years, finally resulting in his book, "The 

 Formation of Vegetable Mould Through 

 the Action of Worms," published in 

 1881 shortly before his death and 

 strangely enough, "best-seller" for his day. 



The most patient experiment of this 

 most patient experimenter was on earth- 

 worms, when he spread chalk over a field 

 and then waited 29 years to dig and learn 

 how deeply the layer had been buried. 

 For his father-in-law, Josiah Wedgwood, 

 had suggested that the sinking of stones 

 into the soil might be due to the earth- 

 worms bringing earth to the surface in 

 the form of their castings. Darwin's 

 research proved this, that the worms, in 

 their burrowings, ate earth for the organ- 

 ic matter it contained, then deposited the 

 excrement castings on the surface. 



He found an average of more than 

 50,000 earthworms to the acre in the 

 tillable soil of England (in America 

 they are fewer) , that some 18 tons of 

 soil per acre passed through their bodies 

 yearly to cover the surface at the rate 

 of an inch thickness every five years, in 

 the course of ages thus burying even 

 large rocks, monuments and ancient 

 buildings. A recent German estimate in 

 Kosmos gives this earthworm horde five 

 or six times the importance of the human 

 race, if we measure them by relative bod- 

 ily volumes. 



The earthworms are an ancient tribe, 

 for we already find fossil burrows of 

 their kindred in Cambrian rocks, some of 

 them crescent in cross-section because 

 their walls caved in when other worms 

 pressed too close in their later burrow- 

 ings. The tribe as a whole is distributed 

 throughout the world, some attaining 

 great size, such as those of Ceylon, n foot 



and a half long, and thick as a snake, 

 But individual species (there being over 

 a thousand) have more limited ranges. 

 The earthworm's habit of coming out 

 of their flooded burrows after a rain has 

 led the Germans to call them "rain- 

 worms." They also come out at night, 

 returning at daybreak to escape their 

 proverbial enemy, for the early bird 

 catches the late worm. They can dis- 

 tinguish between light and darkness, buj 

 the tail is light-sensitive as well as the 



head, and the worms are really blind, and 

 also deaf. Sense of taste they have, for 

 they are choosey of their food, and also 

 a sense of touch that warns them of 

 dangers that shake the ground. But 

 they can do little to protect themselves 

 beyond "Crawling into their holes and 

 pulling the holes in after them" by plug-, 

 ging the openings with dirt. So they 

 survive by sheer numbers and a very re- 

 tiring disposition. 



BOOKS 



THE BIOLOGICAL BASIS OF 

 HUMAN NATURE. By H. S. Jen- 

 nmgs, W. W. Norton & Co., N. Y. $4.00 



We are what heredity and environment 

 make us. Heredity makes us deeply, environ- 

 ment remakes us superficially. Old funda- 

 mental biological truths these are, to which 

 modern genetics has added vastly illuminating 

 details on the mechanism, processes and limi- 

 tations of both inheritance and variation. The 

 whole subject is complex in its working de- 

 tails, yet not too complex in its basic laws. 

 Jenning.s reveals his own clearness of thought 

 by the relative simplicity of his presentation. 

 He has seized upon the basic laws, presented 

 much vital detail in developing them, and so 

 succeeded in makmg a readable book that is 

 sound'y scientific. He makes the genetic ap- 

 proa.h, but reveals the interplay of mutually 



limiting factors, and judges the conflicting 

 theories that the specialists of eugenics, be- 

 haviorism, etc., have overemphasized in their 

 narrower viewpoints. In indicating the limita- 

 tions of each factor, Jennings has given us a 

 singularly whole view of what modem experi- 

 mental biology tells of the making and re- 

 making of our various human natures. 

 FLIGHTS FROM CHAOS, By Har- 

 low Shapley. McGraw-Hill Book Co., 

 N. Y. ?2.50 



THE MYSTERIOUS UNIVERSE. 



Sir James Jeans. MacMillian Co., N. Y. 



$2.25 



Shapley and Jeans present a contrast which 

 has become almost typical among physical 

 scientists. Both write with delightful clearness 

 in apt, popular phrases, and both have taken 

 for their theme a survey of the Universe, with 

 Its unfolding mysteries. Both recognize that 

 we find more mysteries as our vision of the 

 Universe opens up, but what a contrast in 

 attitude from mental chaos towards orderly 

 scientific understanding as we awaken to the 

 uniformities in the behavior of nature. Jeans 

 sees but deeper mystery, finds faith in the 

 involved mathematical metaphysics of the Ein- 

 sceinian ''relativists" and "multi-dimension- 

 ists," takes seriously the new sort of ether 

 composed of permeating mathematical form- 

 ulas, and somehow, among the dimensions, 

 finds a Creator who is essentially mathema- 

 tician. Shapley remains matter of fact, cata- 

 logs the material "systems'* from atom to 

 Universe, but fills his catalog with hints of 

 coming knowledge, an unfolding vision of the 

 vast galactic systems making up the incompre- 

 hensibly immense Universe, from time to 

 time puts the upstart, Man, in his place, and 

 altogether makes his catalog an absorbing de- 

 light. Best of all, he holds true to the well 

 tested scientific method, indulges no metaphy- 

 sical assumptions, mathematical or otherwise, 

 but goes on ever confident that careful obser- 

 vation and experiment will yield their secrets 

 of order in this, our Universe of seeming 

 chaos. The contrast between these authors is 

 one between the patient, plodding scientist 

 who checks his brilliant imagination by labori- 

 ous tests, and the impatient metaphysician 

 who trusts all to the treacherous logic of the 

 human mind. 



MATERIALISM AND VITALISM 

 IN BIOLOGY. By Sir Peter Mitchell. 

 Clarendon Press, Oxford. ?.70 in paper. 

 SPIRAZINES. By Carl F. Krafft. Pub- 

 lished by Author. 2510 "Q" St., N. W., 

 Washington, D. C. ?.50 in cloth. 



These two thin volumes discuss the nature 

 of life from the mechanist standpoint, the 

 one being a summary by an eminent British 

 authority of our progress in understanding 

 what life must be, with something of recent 

 achievements. The other presents a new phy- 

 isco-chemical theory by an American special- 

 ist in organic chemistry. The first is popu- 

 l.irly presented, the second technical. The one 

 tells tales of organic compounds and seem- 

 ingly living sruff made in the laboratory, 

 while the other thrills as a plausible scienti- 

 fic guess at the inner working structure of the 

 stuff of life. 



