OUR PUBLIC SCHOOLS COLUMN

Otago Witness, Issue 3030, 10 April 1912, Page 80

OUR PUBLIC SCHOOLS COLUMN

FOR SENIORS AND JUNIORS. (Conducted by Magisteb, to whom all communications must ho addressed.) [Magister will bo glad to receive Nature notes, marked papers containing educational articles, diagrams, details of experiments, etc., of scholastic interest to teachers" and pupils. Correspondents must use ONLK ONE SIDE of the paper, and whether using a pen name or not. must send both NAiIK ;ind ADDKE33.] THE FLOWERS OF WHEAT, OATS. Etc. From actual inquiry. I find that very few children know that wheat, oats, etc., have flowers. Ask your teacher to run through the parts of an oat flower. Tin lesson on sedges and grasses in Mr Thomson's " Introductory Class Book of Botany for Use in New Zealand Schools " will provide as much information as the ordinary teacher or pupil will want; and ii a magnifying glass is used when a flower is being dissected the pretty little versatile anthers can bo handled, and it can easily bo seen how artificial fertilisation can be done to get new varieties INSECT OR HEXAPOD? By a slip ixsect appeared last week in Mr Ironside's notes, though the mites referred to had not six legs. In " The School World" for last October there is an address by Professor J. W. Gregory, F.R.S.. on " The Scientific Misappropriation of Popular Terms," and from it I am extracting parts referring to the uso of the words "insect," "hexapod," "worm,' and " fish." , , j '•The temptation to adopt an old word for a new idea, instead of inventing a fresh term, is often strong. It saves trouble—at the time. The old word is probably shorter than a now one would have to be, and its use avoids burdening a passage with an unknown and perhaps uncouth term. A sentence in which all the words are familiar appears to present no difficulties; a reader skims lightly over it pleased with the lucidity of the author and ignorant of the fact that it has been misunderstood, as the leading word convoyed to him a meaning different from that intended by the writer. The danger of a passage being misunderstood is more serious than that of its being not understood. It is worse to be misled by a plausible phrase than to be startled or repelled by a correct technical statement. A new word compels a conscientious reader to determine its true meaning, and should help him to a. clear conception of the fresh idea; whereas the use of an old word with a new moaning discourages inquiry and encourages slovenliness in .work and thought. The use of popular phraseology may render scientific literature apparently less strange; but if that phraseology prove to be incorrectly used, the ultimate effect is to increase the divergence between the scientific and popular languages, and the estrangement between science and public opinion. For the scientific use of terms inconsistently with thenordinary meanings is apt to persuade the lavman that the language of science is so different from bis own that it is no use attempting to understand it. "Most sciences have adopted popular terms with new and restricted meanings; and tt tho origin of suoh a word be forgotten, scientific writers are apt to treat any use of its original sense as a popular blunder. For example, zoologists not Only reject spiders from the class of Insecta, but treat tho idea that a spider is an insect as a mistaiko due to simple ignorance. Thus to quote a recent standard work, J. H. and A. B. Comstock, in their ' Manual for the Study of Insects ' (1909, p. 12), remark that spiders ' are often mistaken for insects,' although the authors have tbandoned 'lnsecta' as the name of the class in favour of Hexapoda. The word insect is much older than modern systematic zoology and the class Insecta, Tho word insect is derived .from the Latin insectum, which is based on tho verb insecare, 'to cut into'; and is used for animals whoso bodies are notched or incised into sections. This moaning of the word is well expressed in the definition by Philemon Holland, who is the earliest English author quoted in the ' Now Engish Dictionary ' as liaving used the word insect. In his book. ' The Historic of she World, commonly called the Naturall Historic of C. Plinitw Secundus ' (1601). he Hays, ' Well may they all bo culled Insecta, by reason of those cuts and divisions, which somo have about the necke, and others in the breast and belly ; the which do go round and part tho mem hers of tho bodie, hanging together only by a little pipo and fistulous eonveianco.' "Tho class Insecta was based by t? founder, Linnaeus., on the segmentation of tho body, and not on the number of legs; it therefore included scorpions, millepedes, and spiders. It was not until half a century later that Lamarck excluded spiders from the class Insecta; and as late as 1864 wo find so distinguished a naturalist as Bates remarking that the spide.-s ' Mygales are quite common insects.' Even such a recent standard modern encyclopaedia as the ' Jewish Encyclopedia' retains tho millepedes as insects. The term insect should not, however, bo applied to a coral polyp; 'coral insect' Ls justly denounced as a misleading blunder, due to ignorance of the nature of the coral animal. The term insectum and insect according to their original usage no doubt included worms, and Holland expressly mentioned earth-worms as insects. In many worms, however, tho body is not divided into segments, and worms are therefore early and appropriately oxoluded from insects, so Milton writes in his description of tho bower in Eden: ' Other creature here, Beast, bird, insect, or worm, durst enter none.' " Johnson's Dictionary (first edition, 1755)) accepted a definition restricting insects to animals whoso body is nearly divided in tho middle into two parts. 'lnsects may be considered together as one great tribe of animals; they are called insects from a separation in the middle of their bodies whereby they aro cut. into two parts, which aro joined together by a small ligature, as we seo in wasps and common flics.' This definition, whilo admitting spiders, excluded worms. The present zoological separation of inserts from other air-breathing arthropods is based mainly on tho presence of six logs. Ihe term Hexapoda is therefore more suitable for tho olass as now defined than

Ins»2<r\ and the restriction of Insecta in systematic zoology to a group based not on th'a insection of tho body but on the number of legs is less accurate and appropriate than its previous use in zoology ard in popular English. It would seem better to admit that the spider is an insect, but insi.'t that it is not a hexapod. " The term worm, on the other hand, illustrates cases in which a restriction of popular meaning is both appropriate and convenient. A worm was originally not necessarily one of the Vermes of tho zoologist. Thus the worms mentioned in the Old Testament included various insect larvae. Dr Ridewood tells me that the manna collected by the Israelites in te desert was probably a small lichen, and that the worms bred in it were probably fly grubs; and tho references by Job and Isaiah to worms that cover the dead may include both insect grubs and nematodes. When Job reminds the sinner of the worm that ' shall feed sweetly upon him,' he had in mind tho larvte of blow-flies; and though the worms that ate Herod may have been an endoparasitic worm or fluke, tlie worm that caused the withering of Jonah's gourd was probably a beetle larva. "In ]>opular English, moreover, worms always included snakes, as shown both by Dr Johnson's definition of a worm, 'A small, harmless serpent that lives in tho earth,' and by Shakespeare in Cleopatra's inquiry : ' Hast thou tho pretty worm of Nil us there, That kills and pains not?' "Uniformity between popular and zoological terminology can best be secured in regard to the term worm by inducing tho public to use it only for one of the Vermes, for it. is less necessary to. have one term for all creeping things than to distinguish noxious snakes and centipedes from tho lowly and useful worm. The word n*h illustrates how a popular word may become unduly extended and then bo again restricted with fuller knowledge. The word is of very ancient origin, and was probably originally limited to what the zoologist accepts as fish. The term fish is not derived from the primitive Aryan language, and it was not introduced until tho Latin-Teutonio section had separated from tho Indian and the Greek, at-d as the term was invented by people who apparently had no knowledge of the sea, they doubtless used it for fresh-water fish. The primitive hunters who went to tho coast may have extended it to shellfish, and it was adopted in the English crayfish by a corruption of tho French ecrevisse. When whales and dolphins were discovered, they were accepted as fish in ignorance of their affinities, for suoh acquatic animals as se.ils and otters were never included among fish, siinco tlheir mammalian characters were obvioufi. That whales, porpoises, and their allies are not fish is now admitted in current language, though the old usage survives among whalers The terms whalefishery and seal-fishery are firmly established j mut they are unobjectionable, because those industries have so many important features in common with the capture of fish. Tho general current limitation of fish to the fish of the zoologist is only a return to the primary meaning of tho word." ONLY A WORM!—IS THAT ALL?

Some time before Christmas, when having a short walk, the road I was taking was covered —that's an exaggeration, of course —with worms. Where did they come from? I was asked that question and gave the answer I have sometimes given before: they came up out of tiro wet. Tho weather had just broken after a dry spell, and I suppose the worms were flooded out. Sometimes after such an exodus to tho surface there is a great mortality. Why? 1 cannot, say. Darwin used to think that it was because the worms were ill. but I think it is now supposed that death is caused by something occurring after the wornfs leave the burrows —perhaps extra heat or dryness, a rapid change of temperature or tho extremely rough surface of tho ground. New, it occurred te me that a little information which 1 supplied to some inquisitive young folk might be interesting to somo other young folk, so here aro a few notes. Of course, I am dating with tho ordinary ringed worm, classed in the subkingdom Annelida. WHAT IS A WORM? In the eyes of some a worm "is a mere, blind, senseless, and unpleasantly slimy annelid," but Mr Darwin, says a reviewer, "undertakes to rehabilitate his character, and the earthworm steps forth at once as an intelligent and beneticient personage, a worker of vast geological changes, a planer down of mountain sides ... a friend of man . . . and an ally of the society for tho preservation of ancient monuments." This 1 quote from a notice by "Dinornis" on Darwin's "Vegetable Mould and Earthworms," a book which can now bo obtained for 3s in John Murray's cheap re-issue of Darwin's works. The bodies are series of rings or segments separated by furrows. If you are patient you can count these rings, of which there may be perhaps 200. If you watch a worm pulling itself along you will seo that as it shortens itself hs diameter is increased; this is because its circular muscles are relaxed; and as it lengthens itself its diameter is decreased. In this caso tho circular muscles contract and its longitudinal or lengthwise muscles do the relaxing. The size of tho pupils of our eyes depend uimhi Lin; contraction or relaxing of two similar kinds of muscles. If you turn a worm on to its back and look closely—a magnifying gla.ss will be a great help—you will see on each ring four pairs of bristles which ace as feet and staples, and as a part of the worm is stretching forward the stationary part in hold firm in [wsition by these bristles being piessed well into tho surface. Then, again, you will see on each worm a sirocislly developed flat hand covering several segments. This is called the clitellum. and tho position of this clitellum or saddle fairly indicates whether tho worm is a native or introduced one, the native having this band from 14 to 20 segments from the front one, while tho imported ono has il a few further back —say, from segment 25 to segment 30. And th'is saddle suggests one or two curious facts. The procreating organs of the two sexes are in each worm separate, but not se'ftertilising; .so worms pair just as animals do, having tho sexes separate. In the breeding season over tho saddle there forms a banded sac or girdle containing between it and the clitellum a slimy liquid into which the egg is ejected; this liquid later on is really food for the maturing worm. As time goes on this cocoon or sac, by the worm gradually drawing backwards, gets furtlwr forward and passes over the male

duct containing tho spermatozo.-t (plural of spermatozoon), the male element, and the egg becomes fertilised. Finally, as the worm withdraws itself, the cocoon assumes a bag-like shape, and' in it tho little eggs mature. When turning over the ground, have you seen little balls ofwormlets? You wiil now know, tho origin of these clustres. By-the-t.ye, get some worms with these bands, put them in a box of rich vegetable mould kt.ot damp, and now and again carefully take them out and see if the clite'.lum moves to the front, iinally to work off and become a bag. It will be an interesting piece of observation. (To be continued.)