SCIENCE NOTES

New Zealand Times, Volume XXXII, Issue 7077, 15 March 1910, Page 9

SCIENCE NOTES

(By TV.G.P. in "Sydney Morning Heraid.") THE ACTION OF TUTIN. Dr. Frank Fitehett contributes to the "Transactions of the New Zealand Institute" an interesting paper on the physiological action of tutin. In I<<7, Captain Cook landed a ewe and a ram at Queen Charlotte Sound, with a ™*woi stock-1 ins New Zealand with sheep. Two days later they were bath dead, and no better result was experienced with goats. ■ Many thousands of sheep and cattle have shared the fate of those pioneers, lhe poisonous plant is known by its Maori name, tutu. It is an attractive .shrub, growingvprofusely in the rich soils the first settlers naturally, chose. The hrst issue of the "Lyttelton Tunes' notices the death of three out of five cows just landed. Most of the early farmers or run-holders lost a quarter of their stock through tutu; and many children died th-rouffh eatinsr the ripe berries, which are not unlike black currants. Birds and rabbits eat the plant with impunity; but a stray elephant who fed on it died in four hours. The tutu plant belongs to the genua Coriaria, whose eight or ten species are met with in Europe, North America, China, and 'Japan, the Himalayas, and New Zealand. The European species is sometimes used to adulterate senna with fatal results. The American and New Zealand species are said to be

identical, and this is one of the arguments for a former land, connection.' It is more likely that the order is. very, ancient, andjias died out except in the isolated regions named. ■ Only the seed of the berry is poisonous. From ; the strained juice the Maoris : made a nonintoxicating wine; though the drini is not always above suspicion. The poisonous principle can readily be extracted from the seeds with ether; and a bold experimenter, Christie, took several doses in. 1890. The first substantial advance in too chemistry of the subject was made in 1900, when the crystalline gluco-. side "tutin" was isolated. The immunity* of birds is probably explained by the fact that they do not digest- the seeds. The author gives a long and interesting account of the action of the poison, on all sorts of animals. It is found that the central nervous system is specially affected. POST-GLACIAL TIME AND ANCIENT EGYFI. In the last few years several investigators, working on the rate of recession of Niagara and other waterfalls, have been led Vo estimates of the post-glacial period that are surprisingly short, some of them restricting it to 6000 years. Mr Grenly points out how this conflicts with what we know of ancient Egyptian civilisation. "When the mountain ranges of the northern shore* of the Mediterranean basin were heavily glaciated it is plain that the whole Mediterranean region must have been affected. But the monuments of the First Dynasty in Egypt carry ua back considerably more j than 6000 vears, and they are the work! of a. thoroughly settled and; civilised people. Behind -this, again, lies; the period of prehistorio culture, which goes | back another two or three thousand -ears. In all this time, according io Professor Flinders Petrie, there is no evidence «f climatic change, and_ this would seem to push the last glacial epoch much further back. .EXTINCT MAESXTPIALS. Mr Woodward contributes to the "Geological Magazine" a note on the extinct marsupials of Western Australia. Diprotodoii bones were found in the Kimberley district in 1882, and near Lake Dariot in 1895. Early in 1909 some further specimens were "found at Point Malcolm; but these results were overshadowed by the discovery later in the year of over 2000 bones in the Mammoth Cave, Margaret Eiver. This proves that the marsupial became extinct only in .guite recent times. Some fifty-two species -of marsupials have been chronicled from Western Australia, many of them having become almost or quite extinot in recent years. INVISIBLE LIGHT. The physical cause of light is a wave motion in the ether. 'X'he eye is an organ which is excited by waves of a certain length." Longer and shorter waves do not affect it. Hence there is a long range of-radiation, which the eye does not perceive., In that' part of the spectrum which" we do see there are wave-lengths that affect us more particularly as heat, and wave lengths that af-

feet -us more particularly by the ability to promote chernical action. If we explore the eiid of the spectrum beyond the red with a thermo-electric pile .wo find the first class of wave extending far beyond the region of visible light, and similarly the chemically active rays extend far into the ultra-violet. The terms heat, light, and actinic rays may bo used, so long as wo do not forget that H-e are dealing with ether waves all the time. The same wave length may, or course, affect the eye as light, induce a current in a thormo-pile,' and promote a chemical reaction on a photographic plate. This point is well brought out by using a diffraction grating to obtain the spectrum. The quantity and distribuI lion of radiation in the spectrum when a prism is used varies considerably with the prism substance; owing, of course, to the fact that various forms of glass, or rocksalt or quartz absorb different; wave lengths, and only what they do not absorb' is subsequently .measured, v; With a diffraction spectrum- the maxima of heat,and: .luminosity coincide; though the heat curve still stretches far into the infra-red. Langley's bolometer, an electric contrivance used to explore the spectrum, will detect a temperature dif- J feremcG of .00001 degrees C. A hollow j glass prism filled with carbon bisulphide . shows many of these ultra-red and ultraviolet rays. Filled with iodine such a prism allows only the heat rays to pass. The ultra-violet "rays may be made visible by allowing them to fall on_bisulphate of guinine, in which they induce fluorescence.' Using the analogy of music, to. may say that the light waves cover one octave. At least two octaves of ultra-violet can be detected, and at least seven octaves of infra-red. As a detector of.. ether-waves, .therefore, the eye is a very poor device. . Moreover, what has been said does- not exhaust the list of ether waves by any means. For example, there are the electro-magnetic waves discovered by Hertz, and the waves a thousand feet "or more in length that are ■utilised in. wireless telegraphy; and it is, of course, possible that there .■ are forms of ether-waves till unknown to us, and Sir Oliver Lodge would doubtless cfuoto them as the vehicle of thought transference, while Mr Stead would talk poetically of Julia floating on their bosom.