624 



SCIENTIFIC NEWS. 



[Dec. 21, ij 



Microbia in Artificial Mineral Waters. — Hoch" 

 strtter (Humboldt), after examining samples of such 

 waters for the German Imperial Sanitary Department, 

 finds that pathogenic (disease-producing) micro-organisms 

 die in course of time if kept in closed bottles. The pro- 

 pagation of cholera by water which has been in stock 

 for some days is improbable, but an epidemic of typhus 

 may be produced by water which is from five to seven 

 days old. 



Influence of Exercise upon Digestion. — Dr. Kohn 

 has recently conducted a series of experiments in the 

 laboratory of Professor Rossbach to decide whether 

 rest or exercise after a meal is more favourable to diges- 

 tion. The results showed that exercise decidedly re- 

 tards digestion, leading to the production of large quan- 

 tities of lactic acid in the stomach, while hydrochloric 

 acid and peptone were much below their normal pro- 

 portions. 



Poisonous Effects of Cigarette Smoking. — Dr. W. 

 L. Dudley, Professor of Chemistry in the Vanderbilt 

 University of Nashville, gives, in the Medical News, an 

 account of his researches on this subject. He finds that 

 the most poisonous constituent of tobacco-smoke is 

 carbonic oxide. More injury results from cigarette than 

 from cigar or pipe smoking, because, as a rule, the smoke 

 of the former is inhaled. Without inhaling, the cigarette 

 is not more hurtful than the pipe or the cigar. 



Classification of Lightning. — Arago divides light- 

 ning into three classes : — (i) Zigzag lightnings, or those 

 of the first class, their name indicating their form, and 

 sometimes splitting up into two or three branches. (2) 

 Lightnings of the second class. The light of these flashes, 

 instead of being concentrated in winding lines almost 

 without breadth, covers vast surfaces. They often seem 

 to illuminate the outlines of the clouds from which they 

 emanate. (3) Lightnings of the third class, which take 

 a globular form. 



Black Rivers of South America. — Among the tribu- 

 taries of the Amazon and the Orinoco there are several 

 so-called rios negros — streams of the colour of coffee 

 without milk. During his exploration of those regions 

 M. Marcagno collected several samples of these waters 

 and sent them to Professor Miintz for analysis. The 

 colouring matter consists entirely of free humic matters 

 in the proportion of 16 parts per million. There is 

 scarcely any mineral matter, lime is totally absent, and 

 there are mere traces of potash and oxide of iron. If a 

 black stream falls into an ordinary river, the dark colour 

 disappears at once. 



Preparation of Phosphorescent,? Materials. — Ac- 

 cording to M. Becquerel, very small quantities of foreign 

 matter incorporated with the alkaline earthy sulphurets 

 greatly modify the character of the light emitted after 

 exposure to the rays of the sun. Thus, with traces of 

 peroxide of manganese, a fine yellow light is obtained ; 

 with persulphuret of potassium a green, and with com- 

 pounds of bismuth a blue. An absolutely pure sulphuret 

 of calcium gives off only a feeble light, which soon fades 

 away. This shows the reason why the shells of oysters, 

 etc., after calcination with sulphur, give a more phos- 

 phorescent mass than any pure carbonate of lime. 



The Sale of Mushrooms. — According to Cosmos, the 

 Council of Hygiene of Paris is about to adopt special 

 measures to prevent the sale of unwholesome or poisonous 

 fungi. It is proposed that all wild mushrooms shall be sold 

 wholesale only at one market, where they will be duly 

 examined by experts before being supplied to the retail 

 trade. Cultivated mushrooms require, and will receive, 

 a much less severe examination. It will be forbidden to 

 cry, sell, or hawk mushrooms in the streets, or from door 

 to door. 



Prevention of Hydrophobia in Bavaria. — In the 

 kingdom of Bavaria, during the years 1863 to 1876, 

 there were annually at least 14 cases of hydrophobia 

 out of a population of 5^ millions, and in some 

 seasons the number rose to 23, 29, and even 31. Since 

 the introduction of a new law the number of such 

 fatalities has been three in seven years. Every 

 dog must, on pain of being immediately destroyed, 

 have a responsible owner, and must wear round its 

 neck a metal collar on which is engraven a receipt for 

 the tax. The tax is paid monthly, on which occasion 

 the dog has to be produced for veterinary inspection. 



Public Health. — The deaths registered last week in 

 twenty-eight great towns of England and Wales corre- 

 sponded to an annual rate of i8'6 per 1,000 of their 

 aggregate population, which is estimated at 9,398,273 

 persons in the middle of this year. The highest 

 death-rates, measured by last week's mortality, were : — 

 From measles, 1-7 in London, r8 in Leicester, 2 - 6 in 

 Portsmouth, 27 in Leeds, 3-0 in Oldham, 3*2 in Salford, 

 3'8 in Liverpool, 4*8 in Blackburn, and 77 in Cardiff; 

 from scarlet fever, i - o in Liverpool and in Sheffield, i"6 

 in Derby, and 2 "2 in Blackburn ; from whooping-cough, 

 fo in Birmingham and 1-9 in Cardiff; and from fever, 

 1 - o in Cardiff and i'6 in Salford. The 48 deaths from 

 diphtheria in these towns included 35 in London, 3 in 

 Nottingham, 2 in Birmingham, 2 in Salford, and 2 in 

 Newcastle-upon-Tyne. No death from small-pox was 

 registered in any of the twenty-eight great towns. In 

 London 2,644 births and 1,461 deaths were registered. 

 Allowing for increase of population, the births were 

 41, and the deaths 357, below theaveage numbers in the 

 corresponding weeks of the last ten years. The annual 

 death-rate per 1,000 from all causes, which had been 

 17*2 and 16-5 in the two preceding weeks, rose last 

 week to i7'8. During the first ten weeks of the current 

 quarter the death-rate averaged 186 per 1,000, and was 

 17 below the mean rate in the corresponding periods of 

 the ten years 1878-87. The 1,461 deaths included 139 

 from measles, 30 from scarlet fever, 35 from diphtheria, 

 13 from whooping-cough, one from typhus, 12 from 

 enteric fever, 19 from diarrhoea and dysentery, and not 

 one from small-pox, ill-defined forms of continued fever, 

 or cholera ; thus, 249 deaths were referred to these 

 diseases, being 24 above the corrected average weekly 

 number. In Greater London 3,494 births and 1,764 

 deaths were registered, corresponding to annual rates of 

 33-0 and 167 per 1,000 of the estimated population. In 

 the Outer Ring 12 deaths from measles, 9 from diph- 

 theria, 4 from scarlet fever, and 4 from " fever " were 

 registered. Measles caused 5 deaths in West Ham and 

 3 in Willesden sub-districts. Two deaths from scarlet 

 fever occurred in Enfield, and 4 from diphtheria and 3 

 from "fever" in Tottenham sub-districts. 



