however, burnt away on the seams during the closing of the tins, leaving the solder exposed, and thus not only tin, but lead, is frequently found in the contents of such "protected" goods. Dr. Wynter Blyth said it struck him as possible that Mr. Hehner had rather too readily assumed that the tin in the meat and the vegetables he had examined was in a soluble form, but it was he (Dr. Blyth) thought more likely that very minute particles of tin had been rubbed off by the mere friction of the vegetable or meat, and therefore if it was of frequent occurrence in tinned meats, they had to deal with the question of whether tin in a metallic state was poisonous. When he was in medical practice he frequently gave metallic tin in a finely divided state, and he had certainly never seen any bad action follow. He had given at least 350 milligrammes in a finely divided state, and seen no deleterious action arise from it. With regard to the black precipitant it was well not to be too hasty in putting down that as lead. He had always found considerable difficulty in discriminating between dark discolouration when there was only that to work upon, and that was all there was when there was a mere trace in water. With regard to the symptoms about the excrement being small, it struck him as being on account of the loss of appetite. Dr. Dupré said that in lemonade the lead was traceable to the citric acid used, where, although the action of the lemonade on the vessel in which it was contained was slight, it was nevertheless almost impossible to get citric acid or tartaric acid free from lead. Mr. Dyer said that the letter, to which Mr. Hehner had referred, was written just after an inquest on a child, who had died from eating poisonous tinned meat (or supposed so). Everyone who had tasted it had experienced symptoms of poisoning. The medical man who attended the child did not appear to have made any analysis either of the meat or of the stomach, but he expressed an opinion that the death was due to metallic poisoning, and suggested that it was owing to the hydrochloric acid used in the process of soldering having dissolved some of the tin. He had also had another case, of ox tongue. Cases of poisoning were by no means confined to tinned meats, many cases happened with untinned— for instance, with sausages. Referring to another point, he wished to ask if any member had had any experience in finding the presence of small quantities of zinc. He had had cases of water being contaminated with small quantities of zinc, evidently derived from galvanic tanks. He wanted to know what quantity was considered dangerous. The point seemed rather obscure. Mr. Wigner said, having had much experience in all kinds of canned goods, he was sure that 20 or 30 milligrammes of tin in the pound could be detected by the taste. He had as yet only found one sample of canned fish which was free from tin present in the fish This was a tin of prawns, and they had probably been canned less than a month. He did not think that in the case of fish it was merely as Dr. Blyth had suggested, the mechanical adherence of the tin. In nearly every case condensed milks, which had been kept more than a month or six weeks, tin and lead were both present. As to the meats, he had during the late Food Exhibition examined something like 50 different brands of Tongues, Hams, Chicken, Corned Beef, Roast Beef, &c., and there was only one tin (or brand) in which tin was present in any appreciable quantity; equal to about 0.5 milligrammes in the pound instead of the 10 milligrammes spoken of by Mr. Hehner. He believed the solder, used to fill up the blow holes of the tins, most frequently contained bismuth, and that was at the bottom of the galvanic action which was set up. In the last number of THE ANALYST he referred to a very old can of meat, which was free from tin. With regard to canned fruits he had tried more than 300 varieties, and only about 8 or 10 had turned out bad. He thought an alteration in the character of the tin, or rather of the tinning, would meet the difficulty. Mr. Hehner, in replying, said he did not think there was the slightest doubt that the tin was in a dissolved state, for it was found not only in solid meats but in soups and curries and in compressed meats; also one could plainly see that it was not metallic tin; it was not only on the outer surface that the tin was found, but in the parts near the surface as well. He thought Mr. Wigner was very fortunate in getting samples free from tin, as he himself had obtained his indiscriminately, and invariably found tin. ON THE COMMERCIAL ANALYSIS OF CINCHONA BARKS. THE immense mass of writing on this subject places the analyst, seeking a good commercial process, much in the position of the patient who was killed by having too many doctors. Having, however, had occasion to study every proposed method from time to time, and being often asked for information, I now take the opportunity of laying before our readers the actual process which I find best in practice, and which I have modified from those originally proposed by De Vrij & Moëns. As to the actual extraction of the crude material I will say nothing, except to state that, of the published processes, the extraction of the bark (previously mixed with milk of lime and dried) by successive portions of methylated spirit of 93 per cent., and then converting into sulphates and distilling off the alcohol, is the best, provided the alcohol is only strong enough (which may be cheaply attained by placing a quantity of freshly ignited potassium carbonate in a bottle of the strongest methylated spirit sold) and the bark and spirit are boiled together under an upright condenser. Bark analysts have generally an extraction process, which they keep secret, suitable to the method used by the chief manufacturers for whom they work; and I do not mean to infer that I, in practice, always use the extraction mentioned, but I say it is the best published process. Suppose, therefore, that the bark has been extracted and the alkaloids obtained as sulphates in solution, I begin by the very old method of adding to a very concentrated solution—a distinct excess of sodium hydrate, and shaking out with 50 c.c. of chloroform, and then successively with three quantities of 25 c.c. each. This I find will bring back invariably 5.99 out of 6 grammes of pure mixed alkaloids, and is decidedly the most accurate method, given practice in the way of shaking, &c., so as to get the chloroform to settle quickly. The chloroform should be received into a small tared 5-ounce squat beaker, placed under a Wynter Blyth's recovery apparatus, and the residue dried in the bath at 212°, and then heated in the air bath to 240° F., and the fused mass weighed. The total alkaloids are then dissolved in absolute alcohol, and the solution divided into two equal portions by weight, and treated as follows: Portion A is placed under a burette containing volumetric sulphuric acid (11.6 grms. acid of 1843 sp. gr. in 1 litre of water each c.c. of which=1 gramme crystallized sulphate The of quinine) and titrated until just faintly acid to delicate litmus paper, and the acid used is noted as a guide for future operations. The spirit is then evaporated off, and the residue is dissolved in water at 185o F., using 5 c.c. of water for each c.c. of volumetric acid taken, and if not all soluble, then volumetric acid is to be dropped in until all is dissolved. whole being still kept at 185°, very dilute sodium hydrate (4-74 NaHO per litre) is to be cautiously added, stirring well until the whole is just all but neutral. The amount of volumetric acid used to dissolve over that required at first to titrate, will be an index of the soda required, because the solutions are to be made to balance each other. The whole is now rapidly cooled to 60°, and kept at that point for an hour, and then filtered through a pair of filters previously mutually counterbalanced, and the filtrate received into a graduated c.c. The crystals are washed with 1.5 c.c. of water at 60° for each c.c. of acid used in the titration, and when drained, well pressed, and dried first at 2129, and then gradually up to 240° and weighed, using the outer filter as a tare. The filtrate and washings are measured and ⚫000817 added to the weight of crystals of QUININE SULPHATE for each c.c. of the fluid. If the last drops of water running from the crystals are still acid, then the funnel must be placed over an empty beaker, and the washing continued with saturated solution of quinine sulphate at 60° F. till all free acid is washed away, as if not the crystals will char in drying. measure. Portion B is rendered just acid with hydrochloric acid, the spirit evaporated off, and the residue dissolved in the least possible quantity of water at 100° F. Dilute soda is added to neutralization, and then excess of saturated solution of Rochelle salt, and the whole cooled to 60° for an hour with frequent stirring. The precipitate is collected on a pair of mutually counterbalanced filters, washed with say 100 c.c. of water at 60°, and the filtrate and washings received into a measure. The precipitate is dried at 220° and weighed, using the outer filter as a tare, and ⚫00083 is added for each c.c. of filtrate. The quinine sulphate previously found is multiplied by 915, and the answer is deducted from the weight of the mixed tartrates, and the balance multiplied by ·804 gives CINCHONIDINE. filtrate from the tartrate is concentrated to its original volume, cooled, rendered just faintly acid by a drop of dilute acetic acid, and excess of saturated solution of potassium iodide is added with constant stirring. After an hour or so at 60° it is collected like the cinchonidine, and treated in every respect the same, and weighed, and the weight having had ⚫00077 added for each c.c. of filtrate and washings, is multiplied by 7168, and result is QUINIDINE. The The filtrate from the quinidine is made distinctly alkaline by sodium hydrate, and the precipitated cinchonine and amorphous alkaloid are filtered out in a similar manner, washed and weighed. The precipitate is then treated with spirit of 40 per cent. to dissolve out the amorphous alkaloid and again weighed, and the difference is AMORPHOUS ALKALOID, while the last weighing is CINCHONINE. This is the worst separation in the whole process, but as cinchonine is the least valuable alkaloid it is not of any great consequence. The weight of the cinchonine and amorphous alkaloid together must have deducted from it 00052 for each c.c. of the filtrate from the quinidine hydriodide, and 00066 for each c.c. of filtrate rom the cinchonidine tartrate, and the balance is then the true weight, which, minus the amorphous alkaloid, gives the cinchonine. The process is very expeditious, both portions going on at once, and the whole can be done in six hours. Of course, like all others, it requires experience, especially to see that the neutralizations are carried to the exact point, and the quantities of water properly judged, but, given that, I have frequently got back with it 99 per cent. of mixed pure alkaloids, and for Indian Barks it works very well indeed. There is nothing special in the actual separations, but only in the general manner of working, and the saving of time by using the two solutions, and in the collection on double filters so as to compensate the amount of solution absorbed in every case, and in the allowances which are not exactly perhaps theoretical, but what I have practically found the best. No allowance is mentioned for the solubility of cinchonine because it is very slight and not important. The allowance on the first step of B is a practical one based upon a usual sort of mixture of quinine and cinchonidine, but is to be modified according to the quinine found in part A. In practice, however, it is usually close enough. SUBSTITUTE FOR ALUM IN MAKING BREAD. BY J. NAPIER, F.C.S. I READ with great interest the article by Mr. C. Estcourt, on the above subject, in the October number of THE ANALYST. Having since then obtained a sample of the liquid from Manchester, I am able to give some further information about it. The liquid is called "yeast improver," and is recommended to be used in the proportion of eight ounces per sack of flour (280 lbs.). It is manifest that this solution is not intended as a substitute for yeast, but merely as an adjunct in the case of new flours, and many English flours, where the binding qualities-so essential to making a good, easily-digested loaf-are somewhat lacking. Indeed, with some home flours it is almost impossible to get a satisfactory result. I found the liquid to contain the ingredients, and in similar quantities, as Mr. Estcourt stated phosphates of lime and magnesia, held in solution by phosporic acid. Having certain misgivings as to the purity of the materials used in manufacture, I tested for arsenic and other metallic poisons, but these were completely absent; so also were free sulphuric and hydrochloric acids. Alumina was present to the extent of ·06 per cent. Using eight ounces per sack of flour—making 100 loaves,-thirty-five grains of the liquid will be found in every 4-lb. loaf. The free phosphoric acid in this quantity will not neutralise more than one-tenth the amount of earthy and alkaline phosphates naturally present. The percentage of alumina cannot be any objection to the use of the liquid, there being only 021 grain-equal to 13 grain alum-introduced into each 4-lb. leaf. From the absence of impurities, it is very evident this liquid must be made from very pure materials. This is in striking contrast to the results of analysis of the sample reported to the Salford bench by Mr. J. C. Bell as being made from phosphates of alumina, lime, and magnesia. I think it only remains for our chemical authorities to say whether or not this liquid, in the small quantities used, is injurious to health; but I think there can be little doubt that their decision will be in its favour. The use of bread containing this solution will be decidedly beneficial in the case of children, where a plentiful supply of earthy phosphates is requisite. LAW REPORTS. What is Fair Notice to the Public that Milk Sold is Skimmed :— At Worship Street, William Brainwood, a milk seller, of 480, Old Ford Road, Bow, was summoned for selling milk adulterated with 25 per cent. of water. Mr. B. J. Abbott defended. The evidence of William Walter Burrows, sanitary inspector of Bethnal Green, proved that on August 24th he purchased a pint of milk from the defendant in the street. The defendant vended his milk in the thoroughfares, going about with a van and large cans of milk. In reply to Mr. Abbott, the witness said he saw a printed card in the van stating that the milk was " country skim'd milk, sold as adulterated milk," at 2d. a quart; but he did not see it until after he had stated the purpose for which he had bought the milk. The defendant then told him that it was sold as adulterated. Witness did not believe that the card could be seen, because the defendant went from door to door serving the milk from a can he carried, and the van road. was in the Mr. Abbott relied on the notice, but the magistrate considered that under the circumstances it was no notice to the public. A certificate of Dr. Tidy, analyst for the parish, was put in, showing that an addition of water to the extent of 25 per cent. had been made, besides the abstraction of cream. Mr. Abbott then said that the defendant denied the addition of water, and asked for an adjournment to enable the defendant to have the sample left by the inspector analysed. The magistrate refused to allow any adjournment, and said he was satisfied, in the absence of any defence, with the evidence. Mr. Burrows added that the defendant had before been fined £5. The magistrates now fined him £10 with 2s. costs, or six weeks' imprisonment. Objection that Sample not Personally Analysed by Public Analyst overruled :— At the Hull Police Court, John Stephenson, cow-keeper, of Thearne, was summoned before Mr. E. C. Twiss, Stipendiary Magistrate, for selling, to the prejudice of the purchaser, a quantity of milk which was not of the nature, substance, and quality of the article demanded by such purchaser. The prosecution was instituted by the Urban Sanitary Authority of the Corporation and Mr. G. P. Spink appeared in support of the information. Mr. Laverack represented the defendant. Mr. Dale, Sanitary Inspector of the Hull Corporation, stated that on the morning of the 14th September, he saw defendant snpplying customers with milk, and witness procured from him a pint of new milk, for which he paid 2d. He informed the defendant that he had purchased it for the purpose of being analysed by the Borough Analyst, to whom one-third of the pint was subsequently forwarded. Another portion was given to defendant, and the third part witness retained. Witness put in the analyst's certificate, which certified that the milk contained 25 per cent. of water. Mr. Laverack: He told you he had no milk to spare I believe? Witness: Yes. Mr. Laverack: You got about the last he had? Witness: Yes; there was a little left. William Fox, assistant to the Borough Analyst, deposed that on the date named Mr. Dale brought them a quantity of milk which he had purchased from the defendant. Witness made the analysis. Mr, Baynes was present when it was made, and superintended it. They found only 6.25 of solids, not fat, and the results gave 25 per cent. of water. Mr. Twiss According to your analysis I make it 31 per cent. of water. Witness: Yes, it is 31 as matter of fact. The whole analysis was in favour of the milk. It was not of the nature, substance, and quality of new milk. After cross-examining the witness as to the quantities contained in the analysis, Mr. Laverack submitted that the Act of Parliament was not complied with, first of all because the milk was not personally analysed by the “Public” Analyst ̧ He said it was to be analysed by the "Borough" Analyst. The directions contained in the Act must be strictly complied with. Mr. Dale said that he mentioned Public and Borough Analyst to the defendant. Mr. Laverack considered it hardly fair to his client that this should be stated after he had raised his objection. Mr. Spink said he took it that Borough Analyst meant Public Analyst. In reference to the first objection, Mr. Twiss said that his impression was that if the Public Analyst were present from the commencement of the analysis to its fulfilment, and if he had somebody acting under his supervision the objection could not be sustained. Mr. Laverack said that being the case he would beg leave to call the defendant before his Worship decided the second point. The defendant was then sworn. He stated that on the morning of the 14th inst. his milk was sold out before had served all his customers, and he therefore purchased two gallons of milk from a milkseller named George Smith, for which he paid 14d. a pint. He had disposed of nearly the whole of his extra supply when the inspector came up and purchased a pint of it. He (defendant) bought the milk in belief that it was as good as his own. Mr. Twiss: If that is the case Smith ought to be in defendant's place. Mr. Spink (to defendant): Did you never water your milk? Witness: No. Mr. Spink: Is it the custom of the trade to water it? Witness: Yes, a little sup. His Worship said that defendant and others could not be allowed to sell milk |