469 



SCIENTIFIC SIDE-LIGHTS 



[ovoments 



I ii sic 



until the two parts are separate, and each 

 contained in its own capsule. NEWMAN 

 Bacteria, ch. 1, p. 16. (G. P. P., 1899.) 



2297. MULTIPLICATION, INCONCEIV- 

 ABLY RAPID, OF BACTERIA Simple fission 

 requires but a short period of time to be 

 complete. Hence multiplication is very 

 rapid, for within half an hour a new adult 

 individual can be produced. It has been 

 estimated that at this rate one bacillus will 

 in twenty- four hours produce 17,000,000 

 similar individuals; or, expressed in an- 

 other way, Cohn calculated that in three 

 days, under favorable circumstances, this 

 rate of increase would form a mass of living 

 organisms weighing 7,300 tons, and number- 

 ing about 4,772 billions. Favorable condi- 

 tions do not occur, fortunately, to allow of 

 such increase, which, of course, can only be 

 roughly estimated. But the above figures 

 illustrate the enormous fertility of micro- 

 organic life. When we remember that in 

 some species it requires 10,000 or 15,000 

 fully grown bacilli placed end to end to 

 stretch the length of an inch, we see also 

 Tiow exceedingly small are the individuals 

 composing these unseen hosts. NEWMAN 

 Bacteria, ch. 1, p. 16. (G. P. P., 1899.) 



2298. MULTIPLICATION OF PESTS 



Unintended Results of Commerce. Some- 

 times we unintentionally promote the mul- 

 tiplication of inimical species, as when we 

 introduced the rat, which was not indige- 

 nous in the New World, into all parts of 

 America. They have been conveyed over in 

 ships, and now infest a great multitude of 

 islands and parts of that continent. In like 

 manner the Norway rat (Mus decumanus) 

 has been imported into England, where it 

 plunders our property in ships and houses. 

 LYELL Geology, ch. 39, p. 663. (A., 1854.) 



2299. MULTITUDE OF BIRDS BY 

 NIGHT IN UPPER AIR Telescope Reveals 

 Them against the Moon. Some idea may 

 be formed of the multitude of birds which 

 throng the upper air on favorable nights, 

 during their migration, by using a telescope. 

 One having a two-inch object-glass will an- 

 swer the purpose. It should be focused on 

 the moon when the birds in passing are 

 silhouetted against the glowing background. 

 At the proper focal distance they appear 

 with startling distinctness. In some cases 

 each wing-beat can be detected, and with a 

 large glass it is even possible to occasionally 

 recognize the kind of bird. CHAPMAN 

 Bird-Life, ch. 4, p. 56. (A., 1900.) 



2300. MUSEUM, ANCIENT, OF NAT- 

 URAL CURIOSITIES Cooperation of Con- 

 queror and Philosopher Alexander Aids 

 Aristotle The Lykeum at Athens. In the 

 spring of B. C. 334, Alexander of Macedon 

 crossed the Hellespont and began the famous 

 campaign which left .him master of all the 

 countries between the Danube and the Gan- 



. ges. At about the same time Aristotle, 

 who had been his preceptor, established a 



school at the Lykeum at Athens, and be- 

 gan to gather collections of plants, animals, 

 and minerals, wherewith he illustrated his 

 lectures, delivered while walking up and 

 down the leafy paths which wound through 

 the adjacent gardens. In this undertaking 

 he found in his powerful disciple a most 

 willing ally; for Alexander not only con- 

 tributed a vast sum of money for the pur- 

 chase pf rare objects, but employed thou- 

 sands of men to collect and transport to 

 Athens all that was strange to the Greeks 

 in the distant countries which had yielded 

 to his arms. 



To the gathering of this stupendous mass 

 of material may be traced three results of 

 the highest import: first, the acquisition of 

 the multitudinous physical facts which fill 

 the Aristotelian treatises on natural sci- 

 ences; second, the foreshadowing of the in- 

 ductive method of reasoning; third, the pro- 

 duction by Theophrastus, the Lesbian, of 

 a history of stones, probably based directly 

 upon the study of Aristotle's collections. 

 PARK BENJAMIN Intellectual Rise in Elec- 

 tricity, ch. 2, p. 38. (J. W., 1898.) 



23O1. MUSIC, NATURAL INSTRU- 

 MENTS OF The Wood-cricket of Brazil (the 

 TanandJ Contrivance as of Violin and 

 Bow. A strange kind of wood-cricket is 

 found in this neighborhood, the males of 

 which produce a very loud and not unmu- 

 sical noise by rubbing together the overlap- 

 ping edges of their wing-cases. The notes 

 are certainly the loudest and most extraor- 

 dinary that I ever heard produced by an 

 orthopterous insect. The natives call it the 

 Tanand, in allusion to its music, which is a 

 sharp, resonant stridulation resembling the 

 syllables " ta-na-na, ta-na-na," succeeding 

 each other with little intermission. It seems 

 to be rare in the neighborhood. When the 

 natives capture one they keep it in a wicker- 

 work cage for the sake of hearing it sing. 

 A friend of mine kept one six days. It was 

 lively only for two or three, and then its 

 loud note could be heard from one end of 

 the village to the other. When it died he 

 gave me the specimen, the only one I was 

 able to procure. It is a member of the 

 family Locustidce, a group intermediate be- 

 tween the crickets (Achetidce) and the grass- 

 hoppers ( Acridiidce ) . The total length of 

 the body is two inches and a quarter; when 

 the wings are closed the insect has an in- 

 flated vesicular or bladder-like shape, owing 

 to the great convexity of the thin but firm 

 parchmenty wing-cases, and the color is 

 wholly pale green. The instrument by which 

 the tananfi produces its music is curiously 

 contrived out of the ordinary nervures of 

 the wing-cases. In each wing-case the inner 

 edge, near its origin, has a horny expansion 

 or lobe; on one wing this lobe has sharp 

 raised margins; on the other the strong 

 nervure which traverses the lobe on the 

 other side is crossed by a number of fine 

 sharp furrows like those of a file. When 



