CHEMISTRY. (MISCELLANEOUS.) 



109 



sulfur was present in any form. Applied to 

 minerals the method yields results but ^ittle less 

 certain than when pure oxids or salts are re- 

 duced. The metallic sodium does not need to be 

 kept under naphtha, but may be supplied to a 

 class in small rubber-stoppered, wide-mouthed 

 bottles. But it must be kept away from water or 

 moisture. Large quantities of sodium must be 

 avoided, or the reaction may become dangerously 

 violent. 



Miscellaneous. The address of Prof. J. H. 

 Long, chairman, before the chemical section of the, 

 American Association, was on the Teaching of 

 Chemistry in the Medical Schools of the United 

 States. A historical review of the subject was 

 given, after which the speaker dwelt on the far- 

 reaching importance of chemistry, inorganic as 

 well as organic, to the medical student, and the 

 inadequacy of merely analytical courses. He em- 

 phasized the fact that the burning problems of 

 the physiology, the pathology, and the therapeu- 

 tics, if not of to-day, certainly of the near future, 

 are essentially chemical, and that they are not 

 necessarily confined within the accepted limits of 

 what is called organic chemistry. 



Attention was directed in England during 1900 

 to a considerable number of eases in which per- 

 sons had shown symptoms of arsenic poisoning 

 after drinking beer; and investigations were set 

 on foot to discover whether the beer in the market 

 was contaminated with this drug, and if so to 

 find the source of the contamination. In very 

 many instances traces of arsenic were found in the 

 glucose supplied to the breweries. More care was 

 then taken in the preparation of this substance, 

 and complaints became less frequent. The whole 

 subject of the presence of arsenic in substances in 

 common use was reviewed by Mr. Alfred C. Chap- 

 man, of the Society of Public Analysts, in a 

 paper on Food and Drugs; Some of the Important 

 Recent Events, read before a meeting of Inspectors 

 of Weights and Measures, July 12. The author 

 presumed that the manufacturers would in future 

 take such precautions as would render a repeti- 

 tion of recent experiences impossible; but while 

 this was so, the investigations of chemists had 

 shown that arsenic in minute traces was a very 

 much more frequent impurity than had been sus- 

 pected. The finding of contamination of a sam- 

 ple of effervescent phosphate of soda by that sub- 

 stance had led to the discovery that arsenic in 

 traces was of very common occurrence in phos- 

 phate preparations. Fully 90 per cent, of the 

 1,000.000 tons of sulfuric acid annually produced 

 in England was prepared from pyrites containing 

 more or less arsenic. This arsenic, sometimes to 

 the extent of 1 per cent., found its way into the 

 manufactured acid, and as this was used in num- 

 berless manufactures, it would easily be seen that 

 such manufactured products were all liable to 

 contamination. Traces of arsenic thus found 

 their way into soda, artificial manures, soap, 



flass, borax, and distilled vinegar, while it had 

 een met with in traces in glycerin, baking-pow- 

 der, sweets, etc. Besides its occurrence in the 

 arsenieated minerals in considerable quantities, 

 arsenic was found in traces in coal, and conse- 

 quently in the atmosphere, in many natural river 

 waters, in sea water, in sulfur, in some river 

 waters, and occasionally it might even be present 

 in roots and green vegetables. These facts show 

 how extremely difficult it is to avoid in practise 

 r.iinute traces of this almost ubiquitous sub- 

 stance. In certain cases occurring at Manchester, 

 arsenic had been easily traced back to the fuel 

 used for kilning the malt ; and unless fuel entirely 

 free from arsenic was used, malt, dried on the sys- 



tem in vogue, must necessarily contain traces of 

 arsenic; although with proper care such traces 

 would be so infinitesimal as to bo absolutely neg- 

 ligible in practise. 



The investigations of this subject have also led 

 to the discovery of selenium hi poisonous doses 

 in the beer, and to the suggestion that it may 

 have been present as an additional agent in other 

 cases of poisoning attributed to arsenic. 



The use of sulfuric acid, either as such or in 

 a more portable form as sodium hyposulfito, is 

 advocated by Samuel Rideal as a disinfectant for 

 destroying the bacillus typhosus in potable 

 waters, or in drainage from isolation hospitals. 



Mr. M. Ackroyd showed in a paper read in the 

 British Association that when the observation 

 periods are shortened to daily estimations of 

 chlorin, minimal amounts of rainfall are marked 

 by maximum content of chlorin, and vice verm. 



The conclusion is stated by Samuel Rideal, after 

 the examination of a number of humus residues 

 from the bacterial treatment of sewage, that if 

 the sewage has undergone proper treatment, the 

 small quantity of peaty deposit called by Cam- 

 eron " burnt-out ash," is of the nature of humus, 

 and practically inoffensive; and he quotes Ken- 

 wood and Butler as agreeing that at Finchley 

 in 1900 the deposit from open septic tanks could 

 be removed with little offense, and had been 

 spread without nuisance over small areas of land 

 in the neighborhood. This deposit has also the 

 agricultural value of humus. Like peaty matters 

 generally, it has a function in the property of 

 encouraging, when in small quantity, the nitri- 

 fying action in the final oxidation, and itself un- 

 dergoes slow oxidation to carbonic acid and ni- 

 trates. 



The quantity of grain harvested when basic 

 slag is used as a manure depends generally, F. W. 

 Daffert and O. Redmair say, on the proportion 

 of phosphoric acid' in the slag. The rapidity of 

 the action of the slag is in direct relation with 

 the fineness of the grinding of it, and with its 

 chemical nature. The authors propose for the de- 

 termination of the agricultural value of slag to 

 depend on the solubility of the total phosphoric 

 acid in formic acid. A good slag yields 90 per 

 cent, of its phosphoric acid to this reagent. 



A comparative examination was made by Mr. 

 Leo Yignon, as to ordinary properties, velocity 

 of saccharification, and heats of combination, of 

 cotton cellulose, mercurized cellulose, cellulose dis- 

 solved in Schweitzer's reagent and precipitated by 

 acids, and Girard's nitrocellulose. The author 

 found that concentrated alkalies, such as are used 

 in the operation of mercurizing and probably hy- 

 drating, depolymerize the cellulose, without con- 

 ferring any new chemical functions on it. The 

 same is true of diluted acids acting under the 

 conditions necessary for the formation of Girard's 

 hydrocellulose. 



It appears, from experiments described by A. 

 Rossel and E. Laudriset, that the purity of acety- 

 lene gas is as much affected by the manner in 

 which carbid and water are brought in contact 

 for its generation as by the quality of the carbid 

 employed. 



Illustrations of the advantages which engineers 

 have derived from chemical coadjutors are given 

 by Prof. Frank Clowes in a James Forrest lecture 

 on Chemistry in its Relations to Civil Engineer- 

 ing, delivered before the Institute of Civil Engi- 

 neers. Among them, the author mentions as a 

 most striking instance in which the engineer has 

 been supplied by chemistry with suitable con- 

 structive materials the introduction of cheap 

 steel of varying qualities in substitution for costly 



