SCIENTIFIC.

Otago Witness, Issue 1762, 29 August 1885, Page 27

SCIENTIFIC.

— Pneumonia, with rare exceptions, extends from the lungs to the lining membrane of the 1 chest (pleura), and : hence is really 1 pleura-pneu-monia. Its seat is not 'the mdbqos membrane of the bronchial tubes, ds is that i'b'f bro'rfcnitis } nor the general substance of the lungs, as is that of lung fever;* but*>the*air-cells and the neighbouring minute { tubes (bronchioles), which are wholly » destitute* "of * milc'oul membrane. Sometimes it-is almost an. epidemic; 1 ) It often attacks' more than one member of the iamily*. 1 Pleuro-pneumonia J among 'hdrses is a Very'con i; tagious dißease,^and has'sqmetim'e^'gbne through the land, bringing 'ordinary b'ushiesS'to a standstill. What is/the cause, of. pneumonia? 1 One medical writer says that "neither 'cqldsj'bronchitis, pleurisy, asthma,' or' any' other" lung affection induces it; that, in a Jarge .proportion of cases, it is not referable to ' ajliy,. obvious jcausative agency; that, when- it, appears'io. follow exposure to- a cold, it is probable 'that-this' act 9 only as an exciting cailse, co-operating with the action- of a special cause. ' What'is this spec/a] cause ,? This question 'has received, no answer until recently. German investigators of the highest character .believe they haye 1 ' at length found it in a' micr6scopib parasite I ,* t&Us placing pneumonia ,am6hg the germ diseases,. .'The parasites are oval, generally go.in",pair»}.aftd,<unUke all others, enclose themselves— several 'tdge'ther —in a capsule.' On cultivating them out of the body, insulating them in fluid, and injecting, a little of the fluid .into th% 7 two mice,' all oi the mice, died, in from .eighteen ,'tp' foVby'houra. of pneumonia, while the blood showed' the peculiar parasites with their characteristic ! oapfculesi Experiments by means of 1 inhalation'^xhioited the same results. • Different investigators seeia to have confirmed the discovery. • Later-expe-riments show that the lungs of animals which have died of ' pleuro-pneumonia' contain the same parasites in 'large, numbers, and' that the 1 disease is essentially the same.with .pneumonia in man. ' , ,' l _ '"'" ' _ —It will be remembered 1 that'last-'year Mr? Ellis Lever offered a prize of £500' for, the hehi safety-lamp for the use of , miner s. ' In, the result no lamp sent in for .competition fulfilled the required conditions, so that ► the prize was not awarded. But we • may 'be quite' sure' that the offer did much good in turning the attention'of inventive' brains tq,a much-wanted help to our poor miners. The saine'gentleman now offers a similar sum to the discoverer or the inventor of a safe and' efficient Huhstitute for gunpowder in mines. Unfortunately, gunpowder is oheap, and does its w,orkwell ; but there is little doubt that- to it must be attributed many of those sad explosions by which,- during the past twelve months,- nearly Soo' lives' have been lost in this country and abr.oad:' Unle& therefore the hoped-for' point's to some substitute which is cheap, as well as,effective, wo cannot hope that it wilibe^received with any great favour. Some 1 short 'time ago there were favourable reports publisbed'of the behaviour of the lime cartridge, which 'o^ves ita efficiency to the .addition of, jwater instead oi fire. This cartridge is, of» course,- above suspicion, so far as explosion- is 'concerned 1 ' but, like many other iso-called '"inndv^tfoW,"' it has not been generally ' adopted 'in 1 'our collieries. There are many' who urge that the. use of gunpowder in ,our mines should ba rendered illegal ; and although its abandonment would 'probably lessen 1 the'output, the worker's wbufd be relieved of one 1 of the" risks attending 'their, unenviable lot.— Home paper, , . VJ / ,., i .V,<-,\ * '„'.'' — As a result of his forest meteorological in* vestigation, Professor Muttrich, of Berlin,, has arrived ai> ; these definite coiiclusipns :— l. Tho forest exeroised a positive influence. on the temperature of the air. < 2. The daily variations of temperature were lessened by the forest, and in summer more ,than ! winterl 3. The influence of. the .forest was., in summer greater than that of the pine forest, while<in .winter the tempering influence of the .pine, forest preponderated over that of the defoliated forest. An attempt to determine the influence of: the forest on the mean annual temperature' led -to no save results. . '..'.>,'...■>.• — The apparent enlargement Brlhe'suhymoou, and constellations when 'seen near the horizon is one of those facts •familiar to everyone, but of which very, haay explanations ' have been 1 current. Thus it has been accounted, for by" atmospheric refraction; the 'air ; being' supposed in some general way to" JacV as V a«magmfyingglass of varying' power f another explanation was that when the heavenly bodies are seen near the horizon the number of intervening bodies taken in at the same glance make them appear more distant^ and then unconsciously/people' allow fpr the supposed greater ''cllstatico and imaging them larger; and stall another .explanation was 'that when they were seen near the horizon their light was fainter from' traversing a greater thickness of air, so they appeared to be further off # arid were mentally calculated tobe larger. tioris arid going to Nature for genuine facts, M. Paul Strqqbaut . has 6hown'^that the true explanation lies much deeper and requires the exploration of a quite new field in the theory of vision. .He fixed two points onVthe roof of a room., and then he adjusted two points on a wall at the same distance from his 1 eye r as those on the rQoi f so, that they seemed the same distance apart, b»t apfcual, nieasurejoent , showed that the pair of points 'on the wall(on a love^ with his eye) were closer to one another than' the points on the roof. 'To make sure of the fact he repeated the expeirim'ent wJih pairs of small lights hi a dark roonj X and found that a distance oi.&l on.the.wall at the level of the eye seemed;as great as a distance of 100 on the roof at thq sama distance .fi-oni the eye. Observai tions o;i stars brought out the same result. Pairs of stars 'were selected at the horizon and near the zenith which seemed the same distanpe apart, but' star catalogues showed that the disi tances were really as 10$ to 81. In the case of the sun it has been usual to give a partial cxi planation of its apparent enlargement at the horizon by ascribing it. to the dilation of the pupil in the fainter light of morning and even? , ing and its contracting in the brighter light of noon, but this does not apply to M. Stroobaut'g , experimental cqses or io stars. A very simple experiuient showed that it was not the expla; nation' in this case of the sun ; if the sun on the 'horizon is looked at in 'a mirror inclined at 45 'degrees, so that it is seen as \i in the zenith it 'appears smaller than "if.- looked at direct, it •appears "to be the same size as when actually seen in the zenith. As a niatter of fact the ej-e. does not take account of the difference o| brightness of the light at sunset and at noon ; in both lights the pupil is contracted to about' its utmost. But in the case of the moon i^i is different. The brilliance or the light that reaches the'eye through a great thickness of air from a low moon is ' much inferior to that froiii a'riioon in the zenith, so that the pupil of the eye is larger when it looks at the moon on the" horizon 'than when in the zenith! In ihis case, both effects combine' to p'ro'duce i the 'remarkable difference between 1 the sjze of the rriopri' when jow and when h^gh that '}s ' familiar tp every

tme ; measurement shows that sometimes a high moon appears to be only six-tenths of the size of a low moou. The question is now one for specialists ' in the theory of vision to take up and explain why the eye behaves so differently under so slightly different circumstances. . v