54 



SCIENCE- G OSSIP. 



Ip 



CHEMISTRY 



conducted by c. ainsworth mitchell, 

 b.a.oxon., f.i.c., f.c.s. 



Safety Vessels for Inflammable Liquids.— 

 These vessels, which have been introduced by 

 Henze & Co., are constructed on the principle of 

 the Davy Safety Lamp. The inlet and outlet tubes 

 are protected by fine wire gauze, so that any vapour 

 becoming ignited burns harmlessly on the exterior, 

 without causing the whole contents to take fire. 



Vegetable Eennet. — Ferments which closely 

 resemble in properties the well-known enzyme of 

 the animal kingdom {ante, Vol. VII., p. 369) are 

 found in numerous plants. According to Linne, the 

 juice of Pinguimila vulgaris has long been used in 

 Lapland to coagulate milk, whilst the Hindoos, 

 who avoid animal rennet on religious grounds, em- 

 ploy an extract of the seeds of Witlumia coagulans, 

 a member of the Solanaceae for the same purpose. 

 Peters detected milk-coagulating enzymes in figs, 

 artichokes, and thistles, and Green discovered a 

 rennet in the germinating seeds of the castor oil 

 plant, which was rendered active on treatment 

 with dilute acids. 



Action of Cold on Bacteria. -Bacteria 

 possess extraordinary powers of resisting cold. 

 Thus Pictet and Young exposed cultivations of 

 anthrax bacilli to a temperature of — 76° C. for 

 twenty hours without destroying their vitality, 

 and similar results were obtained by Colemann 

 and Mickendrick, who found bacteria to be capable 

 of developing after being exposed to temperatures 

 of -6° to -130° C. Yet, although cold does not 

 destroy micro-organisms, it prevents their develop- 

 ment, so that putrefactive bacteria remain quiescent 

 in frozen meat. There are, however, certain non- 

 putrefactive bacteria which can develop on meat 

 which is kept only at 0° C. instead of several 

 degrees lower. To this cause Lafar attributes the 

 unpleasant flavour sometimes acquired by meat 

 which has been kept for several days in an ice- 

 chamber. This has been confirmed by Popp, who 

 states that in cement-lined storage chambers the 

 walls when moist swarm with bacteria, which when 

 grown on beef-gelatin produce a mouldy flavour, 

 and he considers these to be the cause of the 

 objectionable flavour occasionally developed in 

 stored meat. Flesh which has once been frozen is 

 liable to decompose more rapidly than fresh meat, 

 since bacteria can more readily penetrate the 

 loosened intermuscular tissue. 



Artificial Silk. — A new process of manu- 

 facturing artificial silk has just been patented in 

 this country by J. Duquesnoy, of Paris. Cellulose 

 is first converted into nitro-cellulose by treatment 

 with sulphuric and nitric acids, as in the production 

 of gun-cotton. The dry nitro-cellulose is then dis- 

 solved in a mixture of acetone, acetic acid, and 

 amyl alcohol. This solution is filtered and expressed 

 through fine jets, and as the acetone evaporates 

 during the latter process solid fibres are left. 

 These are wound into hanks, which are subsequently 



denitrated, washed with water, and dried. Silk 

 prepared by this or similar processes from cellulose 

 can be identified by its appearance under the 

 microscope, the fibres resembling amorphous rods 

 without a central tube. A chemical test has been 

 devised by M. Duyk, who treats the material with 

 an ammoniacal solution of a nickel salt, which dis- 

 solves natural silk, but does not attack the artificial 

 fibres. Artificial silk is frequently " animalised " 

 by being treated with a special varnish obtained 

 from the decomposition of natural silk or wool. 



Arsenical Gold Pyrites in Spain. — The 

 arsenical ore found in the district of Corunna, in 

 Spain, has been reported to contain from 10 to 

 16 dwts. of gold per ton and 20. per cent, of 

 arsenic. The most profitable British ore, mispickel, 

 which occurs in Cornwall, contains only about 

 8 per cent, of arsenic and no gold, and an associa- 

 tion of Cornish capitalists has therefore sent 

 experts to report on the Corunna mines, which 

 should apparently yield very profitable results. 



E. Merck's Annual Eeport.— Herr Merck is 

 to be congratulated, not only on the reliability of 

 the chemicals which he prepares, but also on the 

 excellent report which he issues each year 

 summarising the pharmaceutical researches of the 

 previous twelve months. The present issue con- 

 tains full abstracts of the most important papers 

 published in different journals, together with 

 numerous original communications. The student 

 of medicine or chemistry will find much to interest 

 him in its pages. 



Chemical Changes in Hibernating Bats. — 

 A comparative examination of the composition of 

 a bat before and after its winter sleep has been 

 made by H. Rulot. It shows that there is an 

 absolute loss, but relative increase in the amount 

 of water. The fat diminishes, gradually at first, 

 but with increased velocity towards the end of the 

 hibernation. There is also a greater consumption 

 of albuminous material in the later months, whilst 

 the proportion of carbon consumed -reaches its 

 maximum between November and April. 



Barium in Boston Spa Water. — The spring 

 of Boston Spa, near Harrogate, had a high 

 reputation for its chalybeate water during the 

 eighteenth century, but with the rise in popularity 

 of Harrogate the spa was neglected, and at the pre- 

 sent day the spring is known to but few. An 

 analysis of the water was made in 1784 by Dr. A. 

 Humber, of Leeds, who found its chief consti- 

 tuent to be sodium chloride with smaller quantities 

 of calcium and magnesium chlorides, iron car- 

 bonate, and silica. Until the water was recently 

 analysed by Mr. P. Richards the presence of 

 soluble barium was unsuspected. According to 

 Mr. Richards the water is bright and sparkling, 

 and has a slightly bitter taste. On standing, it 

 becomes turbid and gives a slight deposit consist- 

 ing mainly of iron oxide. It contains 1,271 parts 

 of solid constituents in 100,000, of which -11 parts 

 are barium chloride and only L50 part iron car- 

 bonate. The presence of barium in natural 

 spring waters in England and Wales has been 

 recorded once or twice previously. Thus Dupre 

 and Vasey found 9 - 45 parts per 100,000 in the 

 water of Llangammarch Well ; and in 1899 

 J. White published analyses of waters from deep- 

 well borings at Ilkeston, in Derbyshire, which 

 contained from 38 to 40 parts of barium chloride 

 per 100,000. 



