FARMERS' REGISTER— CANADA THISTLES. 



29 



the water with which the milk was dikited. liut 

 tills adulteration was too obvious to the senses. 

 Any person even of indillercnt delicacy ot" palate, 

 could detect the altered taste of the niilic; and be- 

 sides, after too hours' rest, the flour sank to the 

 bottom, restoring the translucent blueness of the 

 milk, and pointing out the nature of the fraud. 

 To ])revent this mconvenience, the dealers boiled 

 the tlour in the water before mixing it with the 

 milk; and in this way an opaque mixture was pro- 

 ciH-ed, which retained its opacity on standing. As 

 even with this addition the fabricated liquid had a 

 flat taste, sugar or sugar-candy was dissolved in it, 

 by which means the peculiar sweetness of the 

 milk was partly restored. This adulteration, how- 

 ever, has become so easy of detection by means 

 of iodine, which renders the mixture blue by its 

 action on the fecula of the flour, that M. Barruel 

 believes that the fraud now described is very little 

 practised in the present day at Paris. In Britain, 

 where the municipalities take no charge whatever 

 of the purity of this most important article of food, 

 it may be presumed that the adulteration with 

 flour, sugar, and water is common enough, as it 

 is a simple and cheap mode of accomplishing 

 every purpose of the fraudulent dealer. The best 

 mode of proving the presence of farinaceous mat- 

 ter in such mixtures, is to heat the milk with a 

 little sulphuric acid, to coagulate the casein, to 

 filter the whey, and then to add to the latter the 

 tincture of iodine; upon which a fine blue color 

 will be struck. Driven from this species of adul- 

 teration, the Parisian dealers have latterly resorted 

 to another so ingenious, that M. Barruel con- 

 ceives they could not have discovered it, without 

 the aid of some scientific person. The method is 

 simple, so cheap, that for ten-pence the opacity 

 and color of the milk may be imparted to thirty 

 English pints of water, and so far secret that no 

 disao-reeable taste is conununicated. This is 

 nothing more than the employment of an emul- 

 sion of almonds, for which some dealers, more 

 greedy and less cautious than the rest, have sub- 

 .stituted hemp-seed, which however, is apt to im- 

 part an acrid taste. By either of these means the 

 milk may be diluted to an indefinite extent; and 

 the only corrective required is a little sugar-candy 

 to remove the flat taste. A peculiar advantage 

 possessed by this mode of adulteration over every 

 other is, that the vegeto-animal matter or vege- 

 ble albumen of the emulsion by which the oifof 

 almond is held in suspension, is coagulated, or 

 curdled, like casein, by acids. The method re- 

 commended by M. Barruel for detecting the fraud 

 is founded on two circumstances, — the greatly in- 

 ferior quantity of coagulum formed by acids in the 

 mixture of milk and almond emulsion, compared 

 with that formed in milk alone, and the facility 

 with which, by kneading the coagulum with the 

 fingers, oil may be squeezed out of the former, 

 while none exists in the latter. On examming 

 carefully four dilferent specitnens of pure millT, 

 procured from different quarters in Paris he found 

 that 300 parts of each, coagulated by heating 

 them with an equal volume of vinegar, gave each 

 a quantity of curd, which, when well drained, and 

 equally pressed between folds of bibulous ])aper 

 weighed 29 parts; and that the same quantity of 

 milk taken from a cow in presence of a person 

 sent to procure it, gave 30 parts of curd. He then 

 found, that when the same milk was mixed with 



various portions of water, the quantity ol curd was 

 exactly in the inverse ratio of the ])ro]iortion of 

 water added. The water, therefore, did not pre- 

 vent any portion of the curd i'rom being throAvn 

 down by the usual modes of curdling the milk. 

 He next found, that, if a given quantity of sugar 

 was added to the mixture of milk and water, the 

 quantity added could be separated exactly by evap- 

 orating the whey to the consistence of an extract, 

 heating this with alcohol, filtering the alcoholic 

 solution, and evaporating to diyness. He then 

 also found, when equal parts of almond emulsion 

 and milk were mixed together, 300 parts of the 

 mixture, curdled by vinegar as above, gave 16^ 

 parts of curd; and that the same quantity of mix- 

 ture containing two parts of emulsion to one of 

 milk, gave only 10 4-5th parts of curd. So that 

 filthough, as was to be expected, the adulteration 

 with almond emulsion did not lessen the quantity 

 of curd to the same extent as adulteration with 

 water only, yet the decrease was very great, and 

 very nearly in the ratio of the quantity of emulsion 

 added. Lastly, on placing pure curd on white 

 paper, no oily matter was thrown out; but the curd 

 procured from the mixture of milk and almond 

 emulsion, besides being less firm than the former, 

 gave out in 24 or 48 hours, a quantity of oil suf^ 

 licient to stain the paper. Another adulteration 

 to which milk is subjected in Paris, is with carbo- 

 nate of potass or soda. The object of this va- 

 riety of adulteration is, in the hot summer months, 

 to prevent the milk from becoming sour and curd- 

 ling, or to break down the curd and correct asces- 

 cency when the milk has actually become spoiled. 

 In this process, acetate of potass or soda is formed. 

 Neither of these salts, in moderate quantity, is 

 injurious to the health; indeed, acetate of potass 

 exists naturally in milk, and is the source of some 

 embarrassment in the detection of the present 

 fraud. The mode of analysis adopted by M. Bar- 

 ruel is as follows: — As the alkaline acetates are 

 converted by incineration into carbonates, he en- 

 deavored, by means of this property, to ascertain 

 the quantity of alkali naturally contained in whey. 

 He therefore, evaporated a certain quantity of 

 whey to dryness, incinerated the residue in a pla- 

 tinum crucdilc, and procured an alkaline ley from 

 the remainder, which by the process recommended 

 by Decroisil, tor measuring the strength of alka- 

 line fluids, indicated from one and a half to two 

 degrees of alkalinity. Hence any increase of 

 alkaline strength above the last of these points, 

 must be considered as owing to the intentional ad- 

 dition of carbonate of potass or soda. This is 

 evidently the mostdilBcult of the processes recom- 

 mended for detecting the various adulterations 

 specified in M. Ban-ucfs paper. Indeed a chemist 

 alone could conduct it. The others may be easily 

 executed by any body. 



CANADA THISTLES. 



From the Genesee Fanner. 



I have recently noticed in the Genesee Farmer 

 several articles on the destruction of the Canada 

 thistle; but none of them seem to reach the root 

 of the evil. I am, however, pleased to see the 

 public attention draAvn to the subject. 



The extermination of this pest of our plough 

 fields, is an object of great importance to all farm- 

 ers, Avho are unfortunate enough to have them on 



