Jaxuary, 1929 



EVOLUTION 



Page Eleven 



THE AMATEUR SCIENTIST 



A Monthly Feature conducted by Allan Strong Broms 

 LIFE IN COLD STORAGE TWINKLING STARS 



One onion, one potato, one bean, one 

 egg, some water and heat — sounds like a 

 recipe, but it's just a way to take four 

 forms of life out of cold storage. For 

 plants and animals die or at least sleep 

 off each winter, and must have ways of 

 storing their lives for the next season or 

 generation. Bulb and tuber and seed and 

 egg are just different ways of keeping 

 life in storage until conditions favor its 

 active renewal and growth. All are food 

 stores plus the spark of life, the onion a 

 shortened stem of fattened leaves cuddled 

 up close for warmth, the potato a thick- 

 ened root. 



Slice of Potato, vi-ith starch-containing cells 



Look at a slice of potato, thin enough 

 to be transparent, through a low power 

 microscope and you will see the cells of 

 which it is composed. The tough surface 

 layer of flattened cells constitutes the pro- 

 tective skin, while the rounder, interior 

 cells serve for storage bins. They are full 

 of starch grains which you can see better 

 by staining them with iodine, which al- 

 ways turns starch purple. 



If you doubt the spark of life, give 

 these plants a chance, some soil and moist- 

 ure and warmth and watch them send out 

 shoots ready to climb into the air and 

 light. So with the bean, composed of a 

 couple of leaves swollen with starch food 

 and between them a miniature plant all 

 set to grow when conditions are right. Put 

 some soil in a tumbler and plant the bean 

 at one side right next to the glass, keep it 

 watered and warm and see it sprout, a 

 root directed downward for moisture and 

 anchorage, a leaf stem reaching upward 

 for light and air. Meanwhile the old bean 

 shrivels, drained of the food supply that 

 gave the renewed life its ([uick start. 



So too, the egg-stuff is food-stuff ( how 

 well we know it) encased in a protective 

 shell and with a spark of embryonic life. 

 Three weeks of steady warmth and your 

 chick has its start in life, ready to peck 

 its fat-fed self out of the emptied shell 

 and into the busy world. 



Winter nights are fine for observing the 

 stars for they are longer and usually clear- 

 er, so the stars stand out brighter than 

 ever. But summer or winter, an import- 

 ant difference can be noted between some 

 of the brighter stars. Some twinkle; a 

 few do not. Those that twinkle are true 

 stars, great suns so many millions of mil- 

 lions of miles away that they are reduced 

 to mere brilliant points of light which our 

 strongest telescopes cannot magnify into 

 anything but points. Those that do not 

 twinkle are planets, worlds like our own 

 that revolve around our sun and wander 

 among the true stars. There are only five 

 ever visible to the naked eye, Jupiter and 

 Saturn, the giant worlds, Mars, the red 

 world, Venus, the morning and evening 

 star, and Mercury very close to the Sun 

 and rarely seen, the baby of the system. 

 All the planets are within some tens or 

 hundreds of millions of miles, close enough 

 for even small telescopes to show their 

 round disks illuminated by the sunlight. 



Why do true stars twinkle and planets 

 not? We will find the reason in our own 

 eyes. The retina of the eye, that inner, 

 sensitive surface on which the light falls, 

 consists of minute columnar cells packed 

 close together with their small ends facing 

 the light. The image of a planet's disk, 

 focused as on a ground-glass by the cam- 

 era-lens of the eye, is large enough, even 

 though the naked eye cannot see it as a 

 disk, to overlap several of the cell-ends so 

 that some of them are constantly lit up and 

 the light appears continuous. The disked 

 planet therefore does not twinkle. 



The light image from a true star, how- 

 ever, is a sharp point, so small that it does 

 not overlap from one sight-cell to another. 

 As it shifts from one cell-end to the next, 

 it leaves the sensitive cell center and 

 passes over the blind edge before reaching 

 the center of the next. The light sensa- 

 tion is interrupted and the star appears to 

 twinkle. If the image could be held steady 

 on a single cell-center, it would not twin- 

 kle, but the eye itself is never steady 

 enough and even if it were, the moving 

 currents of miles-thick air between us and 

 the star refract its light beam most un- 

 steadily, so that the star seems to be jump- 

 ing around slightly. The old verse now 

 reads 



T-zvinkle, tirinkle. little star, 

 Noiu we knoiu just tuhat you are. 



Wv^ 



Bean-life out of seed-storage. 



WINTER COATS 



With the coming of winter snows, sev- 

 eral northern animals would find them- 

 selves conspicuous in dark coats of fur or 

 feathers against the whitened ground were 

 it not that nature had evolved a seasonal 

 change of color for their protection. The 

 Arctic Fox, for instance, changes its coat 

 with the seasons, having a dark one to fit 

 with the darker ground of summer and 

 a white one to go with the winter's snows. 

 As the fox hunts by stealth, the advantage 

 of seasonal coloration is obvious. The 

 stoat lives and changes color the same way. 



Similarly, hunted animals such as the 

 grouse, ptarmigan and mountain hare 

 change color seasonally to help hide them 

 from predacious enemies. The ptarmigan 

 has even a third coat for autumn, with 

 patches that break up its bird shape into 

 shapeless blotches when viewed against 

 any solid-colored background, dark or light. 



Such an animal as the polar bear, living 

 always among arctic snows and ice .fields, 

 keeps its white coat throughout the year 

 and of course the animals of temperate 

 zones have coats blending with the ordin- 

 ary darker backgrounds. In any case, the 

 coat habit acquired through evolution is 

 that which givc5 advantage in the struggle 

 for existence. Hunter and hunted alike 

 gain by being inconspicuous. Natural 

 selection does the rest. 



CELEBRATE DARWIN 

 ANNIVERSARY 



"On the 12th of February 1809 two 

 babes were born whose names are known 

 to every school boy and girl in the land, 

 Abraham Lincoln and Charles Darwin. 

 The Colorado Rationalist Association will 

 celebrate the 120th anniversary of this 

 event the evening of February 12th, 1929. 



Through the columns of your paper will 

 you please urge other societies to do like- 

 wise. One of these men emancipated 

 four million human beings from the chains 

 of slavery, the other has emancipated 

 millions of human minds from the ignor- 

 ance and bigotry of the middle ages. Is 

 it not fitting that they should be remem- 

 bered by the present age?" 



O. O. Whitenack. Secy. 



SHALL WE PUBLISH 

 "THE PROOFS OF EVOLUTION" 



AS A PAMPHLET? 

 Dr. G. L. Howe, of Rochester, writes: 

 "Are you planning to publish in pamph- 

 let form, "Proofs of Evolution", concluded 

 by Henshaw Ward in the November issue 

 of EVOLUTION? 



"This is by far the most clearly put and 

 most conclusive thing along this line that I 

 have yet seen, and I myself should like to 

 have several copies in pamphlet form." 



We agree with Dr. Howe that Henshaw 

 Ward's "The Proof of Evolution" fills the 

 bill for a pocket sized pamphlet, and shall 

 publish it if there is sufficient demand. Tt 

 would retail at 10c a copy, and come in 

 hundred lots at not more than 5c. Advise 

 us right away how many you'd take. 



