August, 1929 



E\-OLUTION 



Page Elevex 



The Amateur Scientist 



A Monthly Feature conducted by Allan Strong Broms 

 PLANT OR ANIMAL— WHICH: 



We rarely have trouble distinguish- 

 ing plants from animals. Usually ani- 

 mals can move and plants not, animals 

 having nervous reaction systems, 

 while plants have not. But Venus Fly- 

 trap and various sensitive plants do 

 react by movement and some very low 

 one-celled plants actually travel. Also, 

 sponges, which are animals, anchor 

 themselves and just vegetate. So tlie 

 scientist amplifies the popular tests by 

 considering methods of getting food. 

 details of structure, development, be- 

 havior, etc. But even the scientist is 

 stuck when he meets the slime-mold-. 



jelly has disappeared shaping itself into 

 most elaborate and beautiful spore 

 bearing fruits. These are distinctive 

 for each species and are easy to pre- 

 serve. If you know what to look for, 

 you can probably find some in your 

 own yard. 



But the first time you had better get 

 a guide who knows w^hat to look for 

 and where. But guides are few. The 

 New York Microscopical Society has 

 one in Robert Hagelstein who has spe- 

 cialized on the iIyceto::oa, for he thinks 

 them animals, and takes us on a couple 

 of "hunting trips" during the year. 



Three common slime-molds on decaying wood; sporangia of Trichia; of Stemonitis 

 (Plasmodium remnant at base) ; and of Hemitrichia (with Plasmodium) 



He does not know for sure what they 

 are — plants or animals. Some think 

 them plants and call them Myxomy- 

 cetes (slime-fungi), while others dis- 

 agree and call them Mycetozoa 

 (fungus-animals). 



What makes the slime-mold so mys- 

 terious is that it lives its feeding life 

 as a moving animal, and then settles 

 down and reproduces itself by very ob- 

 vious plant spores. As an animal, its 

 working body is a mass of naked jelly 

 called a Plasmodium, suggesting the 

 term "slime," which slips along slowly 

 and engulfs its food like that simplest 

 of known animals, the amoeba. While 

 common in forests, in black soil, 

 fallen leaves and decaying logs, it 

 is seldom noticed, its shapeless yel- 

 low or other colored mass look- 

 ing like nothing in particular. 

 The Plasmodium lives in wood and sub- 

 stratumand appears on the surface only 

 when ready to fruit ; sometimes it seems 

 to be nothing but a wet spot on the log; 

 usually it is inconspicuously small, oc- 

 casionally eight inches across. 



It is easiest to recognize at its plant 

 stage, although it is then just a scatter- 

 ing of small, almost microscopic, 

 spore cases. But it really looks like 

 something, especially if you get a good 

 close-up through a magnifying lens. 

 Almost over night, the Plasmodium 



Sunday morning, July 7th, for instance, 

 we boarded the ten o'clock Long Isl- 

 and train in New York for Mineola 

 where he met us. He took us to a 

 damp forest kettle-hole on the edge 

 of the terminal moraine left by the last 

 great Ice sheet. First he warned us 

 against poison ivy and gave us an anti- 

 dote to wash our hands with (one part 

 of ferrous chloride to nine parts each 

 of water and glycerine). Next he 

 showed us samples from his own col- 

 lection and then turned us loose among 

 the dead leaves and rotting logs. 



We found plenty of sporangia, but 

 only two or three Plasmodia, One of 

 the latter was a greenish-yellow net- 

 work of slime on the end of a dead 

 twig. Another was just a "wet spot" 

 on a piece of bark, but the wetness 

 showed a pattern, and sporangia were 

 already grown from part of it. Our 

 real harvest was in sporangia. Each of 

 us carried a cigar box and a supply 

 of pins. When we found a colony of 

 sporangia, we broke or cut off a piece 

 of the wood or leaf and pinned it to the 

 bottom of the box. This keeps the 

 specimens from tumbling around and 

 breaking the very delicate spore cases. 

 The later preserving is just a matter of 

 thorough drying and the keeping away 

 of insects. 



Our guide told us we had a really 



EVOLUTION LECTURES 



We have arranged a course of ten 

 lectures to be given Saturday evenings, 

 Oct. 12 to Dec. 14, inclusive, in the 

 Labor Temple, 14th Street and Second 

 Avenue, New York. 



The general subject will be "Evo- 

 lution: The Master Key," the idea be- 

 ing not merely to present the conven- 

 tional evidence for evolution, but 

 ■ rather to show how the idea of evo- 

 lution illumines every field of natural 

 science today. 



Four of the lectures will be given 

 by Allan Strong Broms, our science 

 editor, whose course of lectures was 

 so well received last spring. The other 

 six will be offered by authorities in the 

 fields of Biology, Anthropology, As- 

 tronomy, Geology, Psychology and 

 Education who will tell how the fact 

 of evolution helps them to solve their 

 special problems. Detailed announce- 

 ment will appear in our next issue. 



In the meantime we invite our 

 friends to take course tickets in ad- 

 vance to furnish the necessary funds 

 for advertising. Admission to single 

 lectures will be 50c, but those order- 

 ing in advance will get HALF PRICE, 

 that is TWO tickets for the entire 

 course of ten lectures for $5.00. May 

 we hear from you? 



The Duck-baied Platypus 



A Rhyme, 

 by Walter C, Kr.\atz 

 Of all the Mammals the one most queer, 

 On all this wide, old, mundane sphere. 

 Is the so-called duck-billed platypus. 

 Four legs and fur like a regular "cuss"; 

 But minus teeth ; has bill for eats. 

 Though nourishing young on tiny teats. 

 She lays her eggs like a regular bird, 

 Or reptile, no matter if it seems absurd. 

 It means to us who are able to think : 

 This beast is a real connecting link. 



poor day, though we felt quite happy 

 in having found so many after such a 

 recent opening of our eyes. But it 

 seems there are three hundred species 

 throughout the world and this one 

 kettle-hole had already yielded about a 

 hundred, a couple of them quite new. 

 We had nothing like that and he was 

 really disappointed, for he knew his 

 logs by their first names and expected 

 much more of them, especially when 

 he brought company. However, there 

 is another day coming, for the slime- 

 molds are to be found from March to 

 December, and we are to have another 

 "hunt" on September 29th, the same 

 guide, the same place, the same train, 

 and the same good time. Incidentally, 

 everyone is invited. .Tust bring your 

 lunch and a hand magnifier. 



