254 



SCIENCE- G OS SIP. 



CONDUCTED BY C. AINSWORTH MITCHELL, 

 B.A.OXON., F.I.C., P.C.S. 



Food Preservatives Inquiry. — The Depart- 

 mental Committee of the Local Government Board, 

 appointed in July 1899 to investigate into the use 

 of preservatives and colouring matters in food 

 products, have just issued their report in the form 

 of a Blue Book of 500 pages. The use of boric acid 

 is shown to be very general as a preservative in 

 butter, cream, ham, and potted meats. In the case 

 of the flesh foods the Committee consider that 

 there is no sufficient reason for interfering with 

 the use of boron preservatives, but that the quantity 

 used fcr butter or margarine should not exceed 

 0'5 per cent., and should be accompanied by a 

 notification of its presence and amount. Salicylic- 

 acid or its salts was found in 320 of the products 

 examined, temperance drinks forming nearly half 

 of this total. Formalin was detected in twenty 

 samples, of which thirteen were milk and cream 

 The Committee recommend that formalin be 

 absolutely prohibited, and that salicylic acid be 

 not used in greater proportion than 1 grain to a pint 

 in liquid food, or 1 grain to the lb. in solid food. 

 Further recommendations are that no preservative 

 or colouring matter be added to milk or to any food 

 intended for the use of infants or invalids. 

 Professor Tunnicliffe differs from the rest of the 

 Committee in that he would allow half a 

 grain of metallic copper per lb. as a colouring 

 matter in tinned peas, whereas the other members 

 would prohibit its use entirely. It is to be hoped 

 that the Court of Eeference which the Committee 

 suggest should exercise supervision over preserva- 

 tives and colouring matters may eventually be esta- 

 blished, since new preservatives, not yet tried to 

 any extent, will probably become common when 

 the use of the older ones is prohibited or limited. 



Action op Formalin on Flesh. — Formalde- 

 hyde has been made the basis of many meat 

 preservatives such as " carnolin," which is a very 

 weak solution slightly acidified ; but according to 

 the results of different observers it has not proved 

 successful. Ehrlich, for instance, found that an 

 8 per cent, solution preserved horseflesh perfectly, 

 but that a very unpleasant odour was developed. 

 Beef treated with the same solution was equally 

 preserved, and did not develop the odour of horse- 

 flesh ; but on the other hand the meat was only 

 fit to be eaten for a short time after the addition 

 of the preservative, owing to the chemical changes 

 caused by it. According to Bloxam, too, fish 

 treated with formaldehyde becomes so hard as to 

 be unsaleable, even when the preserving solution 

 only contains 1 part in 5,000. It is an interesting 

 confirmation of these statements that a large 

 consignment of birds' skins recently imported from 

 New Zealand have become absolutely rigid. The 

 cause of this change is the combination which 

 takes place between the formaldehyde and the 

 albuminous compounds in the flesh, with the 



formation of remarkably insoluble substances. 

 This hardening influence on animal tissues must 

 necessarily render meat less digestible, and in fact 

 it has been found that as little as 0-2 gramme of 

 formaldehyde interfered with the artificial peptic 

 digestion of blood fibrin, so that the recommen- 

 dation of the Preservatives Committee {supra) is 

 fully justified by these facts. It is interesting to 

 note that while formaldehyde is a powerful anti- 

 septic for bacteria, it does not inhibit the growth 

 of moulds or yeast. The writer has succeeded in 

 cultivating an exceedingly pure yeast in a solution 

 containing sufficient formaldehyde to prevent 

 bacterial growth for weeks. 



Water of the Dead Sea. — The most remark- 

 able characteristic of the water of the large inland 

 lake which receives the river Jordan is its great 

 density, which far exceeds that of any commonly- 

 known natural water. So striking is this property 

 that it has attracted the attention of every traveller, 

 and is the origin of the many marvellous legends 

 found in old and mediaeval literature. Sir John 

 Maundeville, for instance, whose "Travels" were 

 published between 1357 and 1371, wrote: — "And 

 neither Man, Beast nor any thing that beartth Life 

 in him may die in that Sea. And that hath been 

 proved many times by Men that have deserved to 

 be dead, that have been Cast therein and left there 

 for 3 Days or 4, and they might never die therein ; 

 for it receiveth no Thing within him that beareth 

 Life. And no Man may drink of the Water for 

 Bitterness. And if a Man Cast Iron thereon it will 

 float above. And if Men Cast a Feather therein 

 it will sink to the Bottom, and these be Things 

 against Nature." Lavoisier, who analysed somn 

 of the water in 1778 by the imperfect methods 

 of analysis at his disposal, found it to contain 

 46'6 per cent, of solid matter, consisting of 40 per- 

 cent, of calcium and magnesium chloridi s and the 

 remainder of common salt. The specific gravity 

 was 1-2403. The present writer has recently had 

 an opportunity of examining a specimen of the 

 water brought back some years ago. This had a 

 specific gravity of 1-203, or, in other words, agallon 

 of it would weigh approximately 12 lb., as com- 

 pared with ordinary sea-water, a gallon of which 

 weighs about 10|- lb. The density of the water 

 was due to the saline matter in solution — 24 - 46 per 

 cent., as against about 35 per cent, in sea- 

 water. This large proportion of salts is due 

 to continuous evaporation of the water, and the 

 introduction of fresh quantities charged with 

 mineral matter from the surrounding soil. The 

 effect of this saline matter on bathers is very 

 striking, the skin rapidly becoming coated with a 

 thin crust of salts on leaving the water. A small 

 amount of organic matter (0'5 per cent.) was also 

 present, probably consisting of bituminous sub- 

 stance derived from the asphalt which is still 

 found floating on the water ((/. Gen. xiv. 10). 

 The salts consisted chiefly of magnesium chloride 

 and sodium chloride, with smaller quantities of 

 calcium chloride and potassium chloride; but these 

 constituents were present in a very different pro- 

 portion from their ratio in sea-water. Calculated 

 into their probable combinations the salts consisted 

 of per cent. : — Magnesium chloride, 9'06 ; calcium 

 chloride, 3-49 ; sodium chloride, 8-52 ; potassium 

 chloride, 2'37 ; iron and aluminium chlorides, 0-55 ; 

 calcium sulphate, 0-148 ; ammonium chloride, 0-029 ; 

 silica, 0083; magnesium bromide, 021 . Total, 

 24 4G0. 



