May 2nd, 1SS7. 



SCIENTIFIC NEWS. 



61 



Leaving lead, the fitting type ot an age of fraud, we turn 

 to one of its companions — zinc. At one time tliis metal was 

 recommended to dairymen for bowls and pans, as causing 

 the cream to rise more readily to the surface. This was 

 really the fact, but the recommcnders overlooked a slight 

 drawback. The fatty matter of the milk and the lactid acid, 

 as fast as formed, dissolve zinc and become poisonous. It 

 is of course known that a moderate dose of the sulphate of 

 zinc causes severe vomiting, and is thus at once expelled 

 from the system ; but in other forms it occasions severe ill- 

 ness. We remember a case which occurred lately in 

 America. Three persons were attacked with every symptom 

 indicating a corrosive poison, and narrowly escaped with 

 their lives. They had been eating " canned " tomatoes. On 

 inquiry it appeared that, in soldering up the tins, the use of 

 resin had been discarded in favour of chloride of zinc, which 

 is cheaper, easier to use, and very poisonous. Perhaps the 

 most serious feature in this case is that, under very conceiv- 

 able circumstances, some innocent person might have been 

 accused of intentional poisoning. 



Of all poisons the most generally-known and dreaded is 

 arsenic, in its various states and combinations. It is not 

 generally introduced into articles of food, though we have 

 heard of a woman who had access to some white arsenic 

 (obtained for the benefit of the rats), and who mistook it for 

 ground rice (!) and made it into a pudding. No less lament- 

 able was the fate of a woman at Huddersfield, who, being 

 troubled with heartburn, bought and took a dose of prepared 

 chalk. By some mistake she had been supplied with so- 

 called French chalk, and in some mysterious manner this 

 French chalk had been mixed with a large proportion of 

 white arsenic. 



But the channels through which arsenical compounds 

 usually enter our bodies are very difierent. Unfortunately 

 not a few of the colours used in the manufacture of paper- 

 hangings and of painters' colours are arsenical. This refers 

 especially to greens, some of the most pleasing of which are 

 compounds of arsenic and copper. On careful analysis, 

 however, arsenic has also been found where its presence 

 seems gratuitous — in greys, drabs, reds, etc. Now, con- 

 cerning the poisoning experienced by persons living, and 

 especially sleeping, in rooms hung with arsenical papers, 

 there has been much discussion, some authorities exaggerat- 

 ing the mischief and some denying it altogether. One emi- 

 nent chemist, who has been practically conversant with the 

 manufacture of" emerald green," holds that if the arsenious 

 oxide present in the colour were given off, either as such, 

 or were first converted into arseniuretted hydrogen, the 

 green colour of the paper would disappear, which is not the 

 case. He points out, also, that the men employed in the 

 manufacture of this substance, and who, when packing it 

 for sale, are enveloped in clouds of its dust, have not been 

 known to suffer from arsenical poisoning, because they get 

 used to it, like the Styrian arsenic-eaters. It is a curious 

 fact, however, that it is (or, at any rate, was at the time 

 emerald green was so fashionable a colour) customary to 

 pay the men employed in its manufacture additional wages, 

 and the hands working at it were changed week by week. 



On the other hand, there is a large amount of incontro- 

 vertible evidence showing the reality of the mischief. Some 

 persons — for all are not susceptible — on having to occupy 

 a bedroom the walls of which are covered with an arsenical 

 paper, are soon attacked with a series of distressing 

 symptoms, and can obtain no relief from medical treatment. 

 But if they try a change of air, or even change one room for 

 another, they forthwith experience complete relief And if 

 they do not return to the same room, or to one papered 

 with a similar material, this relief proves lasting. If, 

 however, they do so return, the symptoms recur also. 



Again, it has been found that some men can work at 

 emerald green making almost with impunity, whilst others 

 would never seem to get, as one might say, acclimatized to it. 

 Among the more common affections are chronic sore throat, 

 inflamed eyes, nervous prostration, sickness, cramp in the 

 bowels, etc. In all these cases the wall-paper has been 

 found, on careful analysis, to be rich in arsenic. From some 

 flock-papers 59 per cent, of arsenic has been obtained by 

 Professor Taylor, the late eminent toxicologist. Another 

 important point in the evidence is that if the arsenical paper 

 is carefully removed and if a non-arsenical paper is put in 

 its place, the room may then be occupied with impunity 

 even by a person who formerly suffered severely. This, of 

 course, proves that, save the paper, there was nothing 

 injurious in the room. 



But wall-papers are by no means the only articles 

 coloured with arsenical preparations. " Emerald green " is 

 in great request for lamp and candle shades, for the backs 

 of playing-cards, for artificial flowers, and for colouring wax 

 or paraffin candles. All such objects are, of course, more 

 or less dangerous for household use. The coloured candles 

 are perhaps the most objectionable, since, as they burn, the 

 poison is diffused in the air. 



We come next to children's toys which are gaily orna- 

 mented with a tempting assortment of poisons. White- 

 lead, red-lead, chrome-yellows and oranges, and arsenical 

 greens are used without scruple. This is the more to be 

 condemned since young children invariably suck or lick 

 anything given them to play with. In the cheaper kinds 

 of toys, the colours are not applied as oil-paints and 

 covered with a good coating of varnish, but are simply 

 mixed with size or even with water. Hence if rubbed or 

 wetted the colour " comes off" with the greatest ease. 



Much mischief has been wrought, in former times more 

 than at present, by poisonous colours used in the decora- 

 tion of sweetmeats, jellies, bridecake, blanc-mange, etc. 

 Here our old friend the arsenical emerald green once more 

 puts in an appearance. Now, for the application of poisons 

 to such purposes there can be no excuse. Cochineal and 

 safflower yield every shade of red ; quercitron bark supplies 

 a yellow, indigo, a blue, and a beautiful green may be 

 obtained by bruising raw coffee and steeping it in white of 

 egg. In some countries official lists have been drawn up 

 showing what colours may be lawfully used for ornament- 

 ing foods and beverages, and which, on the contrary, are 

 strictly prohibited. We have not arrived at such a needful 

 precaution. But, perhaps, the right to poison each other — 

 in the way of business —is one of those liberties which we 

 Britons cannot think of surrendering. 



There is another possible, or at least conceivable form of 

 poisoning which has given rise to sensational statements 

 innumerable. This form has come under notice only since 

 the introduction of the coal-tar colours in dyeing and tissue- 

 printing. No one seeks to deny that some of the primary 

 materials used, such as aniline and nitro-benzol, are decidedly 

 poisonous. Unfortunately, too, the reagent first used for 

 converting a mixture of aniline and toluidine into magenta 

 was arsenic acid. The earlier manufacturers of magenta, 

 too, were not perfectly versed in the art of eliminating the 

 residues of arsenic from their magenta, and this colour con- 

 sequently came into the hands of the dyer and the calico- 

 printer in a decidedly impure condition. And as magenta, 

 besides being extensively used as such, served as the raw 

 material for manufacturing the aniline blues and violets ; 

 hence, not unnaturally, the coal-tar colours were condemned 

 as a whole. 



Another circumstance has here intervened. Some forty 

 years ago the arts of the dyer and the tissue-printer were 

 exercised mainly upon materials destined for outside gar- 



