96 



CHEMISTRY. 



oome mouldy or putrid ; and, in fact, it is within the 

 experience o*f every one who is concerned in medico- 

 legal inquiries, that serious symptoms are frequently 

 traced to the use of food in a modified condition of de- 

 cay. This is especially so with bad cheese, the effects 

 of which on the constitution have been so severe that 

 official investigations have been called for. These 

 effects have been noticed at Schwerin (1823), at 

 Minden (1825), at Hameln (1826), at Greifswald (1827), 

 Frankfort (1828), and elsewhere ; and they have been 

 the subjects of interesting essays by Henneman, 

 Hunefeld, Westrumb. and others. At nrst the effects 

 wore attributed to the copper vessels used in the 

 dairies, and therefore the Austrian, Wiirtemberg, and 

 Ratreburg states prohibited the use of that metal for 

 uuch purposes ; but the subsequent inquiries of 

 Hunefeld, Serturner, and other chemists, established 

 the foot that no metallic poison was discoverable in 

 the cheese. In the police report, which was pub- 

 lished in Frankfort, in January, 1828, informing the 

 public of numerous cases of poisoning in that city 

 from spoiled cheese, it was declared that no poison- 

 ous principle could be detected by chemical reagents. 

 Professor Hunefeld and, subsequently, Serturner, 

 were of opinion that the effects were due to certain 

 poisonous fatty acids analogous to, if not identical 

 with, caseic and sebacic acids ; and they even describe 

 the way in which they are produced in the cheese 

 during 'the process of ripening attributing them to 

 the imperfect removal of the acid liquor from the 

 curd when the cheese was made, or to the putrefac- 

 tion of the curd before it was salted, or to the mix- 

 ture of flour with the curd ; but it is far more likely 

 that the poisonous effects are due, as Vanden Corput 

 supposes, to the* presence of a peculiar mould or 

 fungus. 



Purtfying Water T)y Chemical Ingredients. 

 A scientific commission, appointed in the Neth- 

 erlands, to investigate the practicability of puri- 

 fying the turbid water of rivers and lakes, so 

 as to make it fit for drinking, have submitted 

 their report. They ascribe the prevalent tur- 

 bidity of the Netherland waters to the pres- 

 ence of extremely minutely divided clay, by 

 the aid of which a great deal more of organic 

 matter than could otherwise remain suspended 

 is kept in such an extreme state of division as 

 to pass through filters and deposit, even after 

 many days of rest. The committee availed 

 themselves of the skill and experience of Dr. 

 J. "W. Gunning, of Amsterdam. This gentle- 

 man had found that the perchloride of iron, 

 added to the turbid water of the river Maas, 

 which is an important source of supply for a 

 considerable population of the 'Netherlands, 

 lias the effect of rendering it perfectly whole- 

 some and even agreeable for use : 



To one litre of water, 0.032 grm. of the dry salt just 

 alluded to, and previously dissolved in pure water, 

 are added, and, after well stirring the liquid, it is left 

 quietly standing, to settle, for fully thirty-six hours. 

 A series of very carefully-made experiments has 

 proved that no free hydrochloric acid (the quantity 

 thereof contained in the above-stated weight of per- 

 chloride of iron only amounts to 0.021 grm.) was left in 

 the clarified and purified water, but in order to suit 

 the application on the large scale, and to make assur- 

 ance doubly sure, as regards any acid or perchloride 

 Dung left undecomposed, or rather uncombined, with 

 the organic and inorganic matter of the water, Dr. 

 Gunning has advised that a small, but equivalent, 

 quantity of crystallized carbonate of soda should be 

 also added some hours previous to beginning to take 

 the purified water for use. At Dr. Gunning's request, 

 o scientific gentleman of high attainments, who hap- 



pens to have an excellent opportunity, near Eotter- 

 dam, to try on the large scale this process, has sub- 

 mitted it to practical test, and a quantity of no less 

 than about two hundred and forty thousand litres of 

 Maas water, taken at all times of the year, has been 

 treated by this process, and thereby rendered per- 

 fectly fit for use, and, consumed by various parties, 

 has proved to have been entirely deprived of its 

 property of causing diarrhoea ; moreover, the medical 

 officer in charge of the crew of her Majesty's corvette 

 the Lynx, moored off Kotterdam, in the river, has 

 applied this process to the water taken from the river, 

 and found by experience that the thus purified water 

 has even the good effect of restoring to health such 

 of the crew as had been incautiously drinking the not 

 previously purified Maas water. It is, when using 

 this means of purifying bad. water, of great impor- 

 tance to let the sediment quietly settle ; it occupies 

 about four-tenths of the bulk of the water, which on 

 the large scale will, for security's sake, be submitted 

 to a filtration through fine well-cleansed sea-sand be- 

 fore being sent through the mains of the large water- 

 works intended to be established near Kotterdam for 

 the supply of that town. The quantity of crystallized 

 carbonate of soda which is equivalent to 0.032 grm. 

 of dry_ perchloride of iron is 0.085 grm.; both these 

 quantities are the maximum required to render the 

 Maas water perfectly pure, even at the time when it 



animal charcoal. The result obtained with the Maas 

 water having been so eminently successful, the com- 

 mittee has applied this method to the purifying of 

 water otherwise non-drinkable, such as is met with 

 in many of the smaller canals, brooks, and also pumps 

 yielding surface water of bad quality in many parts 

 of the kingdom, and the results obtained are such as 

 to justify the order that this method of purifying 

 must be applied by authority to a class of waters 

 which j thus treated, become available for use. The 

 precipitate formed by the addition of the perchloride 

 of iron and carbonate of soda, both previously dis- 

 solved, has been proved, by accurate analysis, to con- 

 tain a large quantity of organic matter, which, on 

 being^ ignited with soda-lime, yielded ammonia very 

 largely ; analysis has also proved that, as regards the 

 Maas water, the only addition to its inorganic con- 

 stituents is that of one part of chloride of sodium, by 

 weight, in forty_ thousand parts of water by the ap- 

 plication of this process. Dr. Gunning has found 

 that the effect of the perchloride is not so conspicu- 

 ous with some well waters containing much carbonic 

 acid ; while, moreover, there may exist in some of 

 these kinds of waters, either in quantity or quality, 

 inorganic salts which delay or altogether impede the 

 peculiar mode of flocculent precipitation observed 

 with the above-named Maas and other waters to take 

 place after addition of the iron salt. 



Phosphates in Wheat. Mr. F. Grace Oalvert, 

 in a paper read before the British Association, 

 gave the result of his inquiries into the amount 

 of soluble and insoluble phosphates in wheat. 

 The following is a tabular statement : 



C bran nd IL IIL 1V> Flour ' 



Phosphoric acid com- ) 



bined with sesqui- [ 0.042 0.047 0.037 0.015 0.022 



oxide of iron, ) 



Phosphoric acid com- 1 1.485 1.259 0.657 0.329 0.047 



bined with magne- 1 



sia and a small f ' 144 



quantity of CaO...J 

 Phosphoric acid com- 1 ., fvr1 . n4p . ft Afia A OQn n _., 



bined with potash., f 1 ' 071 1 ' 046 - 459 - 280 ' 758 



Total.... 2.593 2.352 1.153 0.624 0.971 



1 - 942 



- 918 - 529 - 080 



