Constituents 

 Contraction 



SCIENTIFIC SIDE-LIGHTS 



126- 



the spectrum of the gaseous envelope alone, 

 we should obtain a striped spectrum, each 

 bright band of which would coincide with 

 one of Fraunhofer's dark lines. These lines, 

 therefore, are spaces of relative, not of abso- 

 lute, darkness; upon them the rays of the 

 absorbent photosphere fall; but these, not 

 being sufficiently intense to make good the 

 light intercepted, the spaces which they il- 

 luminate are dark, in comparison to the gen- 

 eral brilliancy of the spectrum. TYNDALL 

 Heat a Mode of Motion, lect. 17, p. 512. 

 (A., 1900.) 



622. CONTAGION, SPREAD OF, 

 AMONG SILKWORMS Care Necessary to 

 Exclude Germs One Infected Individual 

 Will Poison Many. To protect the worms 

 from contagion it is necessary to raise them 

 at a distance from where infection has orig- 

 inated, in separate localities, perfectly 

 adapted, that have been cleansed with the 

 greatest care, and after all the apparatus 

 has been most energetically washed to remove 

 all the dust and debris of any preceding cul- 

 ture. And besides, it is necessary to take 

 the most minute precautions not to intro- 

 duce the germ of the malady into the room, 

 especially no germ produced by a contem- 

 poraneous culture, since the contagion is in- 

 finitely more easy with the fresh dust than 

 with that which is dry or old. Just one in- 

 fected worm trailing its body and its dejecta 

 over the leaves can poison a considerable 

 number of healthy worms. PASTEUR Etudes 

 sur la Maladie des Vers a Soie, p. 64. 

 (Translated for Scientific Side-Lights.) 



623. CONTAMINATION, ARTIFICIAL 



Oysters Fattened on Sewage. It is four 

 or five years since Professor Conn startled 

 the medical world by tracing an epidemic of 

 typhoid fever to the consumption of some 

 uncooked oysters. Almost at the same time 

 Sir William Broadbent published in the 

 British Medical Journal a series of cases 

 occurring in his practise which illustrated 

 the same channel of infection. Since then a 

 number of similar items of evidence to the 

 same effect have cropped up. . . . The 

 mode of infection of oysters by pathogenic 

 bacteria is briefly as follows: The sewage 

 of certain coast towns is passed untreated 

 out to sea. At or near the outfall, oyster- 

 beds are laid down for the purpose of fatten- 

 ing oysters. Thus they become contami- 

 nated with saprophytic and pathogenic 

 germs contained in the sewage. NEWMAN 

 Bacteria, ch. 6, p. 229. (G. P. P., 1899.) 



624. CONTEMPLATION, INVESTIGA- 

 TION, EXPERIMENT- The Three Stages in 

 Knowledge of Phenomena. To the mere 

 contemplation of Nature, to the observation 

 of the phenomena accidentally presented to 

 the eye in the terrestrial and celestial re- 

 gions of space, succeeds investigation into 

 the actual, an estimate by the measurement 

 of magnitudes and the duration of motion. 

 The earliest epoch of such a species of nat- 



ural observation, altho principally limited 

 to organic substances, was the age of Aris- 

 totle. There remains a third and higher 

 stage in the progressive advancement of the 

 knowledge of physical phenomena, which 

 embraces an investigation into natural 

 forces, and the powers by which these forces 

 are enabled to act, in order to be able to 

 bring the substances liberated into new com- 

 binations. The means by which this libera- 

 tion is effected are experiments, by which 

 phenomena may be called forth at will. The 

 last-named stage of the process of knowl- 

 edge, Avhich was almost wholly disregarded 

 in antiquity, was raised by the Arabs to a 

 high degree of development. HUMBOLDT 

 Cosmos, vol. ii, pt. ii, p. 209. (H., 1897.) 



625. CONTEMPLATION OF NATURE 



A Joy to Man Its Silent Influence. In 

 reflecting upon the different degrees of en- 

 joyment presented to us in the contempla- 

 tion of Nature, we find that the first place 

 must be assigned to a sensation which is 

 wholly independent of an intimate acquaint- 

 ance with the physical phenomena presented 

 to our view, or of the peculiar character of 

 the region surrounding us. In the uniform 

 plain bounded only by a distant horizon, 

 where the lowly heather, the cistus, or wav- 

 ing grasses deck the soil; on the ocean 

 shore, where the waves, softly rippling over 

 the beach, leave a track, green with the 

 weeds of the sea; everywhere, the mind is 

 penetrated by the same sense of the 

 grandeur and vast expanse of Nature, re- 

 vealing to the soul, by a mysterious inspira- 

 tion, the existence of laws that regulate the 

 forces of the universe. Mere communion 

 with Nature, mere contact with the free air, 

 exercise a soothing yet strengthening influ- 

 ence on the wearied spirit, calm the storm 

 of passion, and soften the heart when shaken 

 by sorrow to its inmost depths. Everywhere, 

 in every region of the globe, in every stage 

 of intellectual culture, the same sources of 

 enjoyment are alike vouchsafed to man. 

 HUMBOLDT Cosmos, vol. i, int., p. 25. (H., 

 1897.) 



626. CONTEMPT OF SCHOLASTICS 

 FOR SCIENCE Medieval Problems Concerned 

 the Future World. The men of the Middle 

 Ages, in fact, endeavored on the one hand to 

 develop the laws of the universe a priori out 

 of their own consciousness, while many of 

 them were so occupied with the concerns of 

 a future world that they looked with a lofty 

 scorn on all things pertaining to this one. 

 Speaking of the natural philosophers of his 

 time, Eusebius says, " It is not through ig- 

 norance of the things admired by them, but 

 through contempt of their useless labor, that 

 we think little of these matters, turning our 

 souls to the exercise of better things." So 

 also Lactantius " To search for the causes 

 of things; to inquire whether the sun be as 

 large as he seems; whether the moon is con- 

 vex or concave; whether the stars are fixed 

 in the sky, or float freely in the air; of 



