98 THE ANALYST. PRESENCE OF II'ETALLIC COMPOUNDS I N ALIMENTARY SUBSTANCES. By B. H. PAUL, 1%. I), F.C.S., AND C . T. EINGZETT, F.C.S. Abstract of Paper read before the Pharmaceutical Con$erence at Plymouth. 1. INTPODUCTION.-~nder the Sale of Food and Drugs' Act a number of prosecutions have been instituted during the last few years, haying regard to the presence of metallic compounds in articles of food.Meanwhile, the knowledge possessed by either chemists or medical men as to the bchaviour of such coinpouuds upon the human system is extremely mcagre. There can be no doubt that many mineral substances exercise a prejudicial influence upon hcnlth, but the mcasure and nature of this influence is in most cases an undetermined quantity, while it is probable that, owing to popular prejudices, a number of harmless substances are assunied t o possess pernicious or poisonous properties.THE ANALYST.99 2 . PRESERVED PEAS AND COPPEEL-A popular food which has been most severely remarked upon is preserved peas. The quantity of sulphate of copper added varies between o m and two p i n s of the ordinary blue sulphate to the tin of peas containing from 9& to 92 ounces of peas, and 150 C.C.of liquor. The question of what influence this copper has upon health is one which has been hotly discussed, and widely differing opinions have been expressed by medical men. It appeared t o us that in order to arrive at a proper knowledge of the physiological influence of the copper contained in preserved peas, it mas desirable to determine the following points :- (1).I s the copper in mere admixture with the peas, or is i t in actual combination ? (2). noes it pass into solution under the influences of the digestive processes ? (3). I s any part or all of the copper thus introduced in the stomach absorbed, or 3. PRESENCE OF COPPER IN ORGANIC TISSUES AND PRoDucrs.--Before proceeding to describe the experiments me have made relative to these questions, we may take note of the fact that from the time of Margraff, Gahn, and Vauquelin, chemists have been acquainted with the presence of copper in organic tissues and products.In view of these facts we deemed it desirable t o examine green peas for copper, and accordingly, two experimcnts were made with this object. 4. METIIOD FOR DETECTION OF Cowm.-The method pursued throughout this inyestigation for the detection of copper may be at once stated ; it consists in burning the suspected matters with a mixture of pure sodic carbonate and potassic nitrate, causing complete destruction of all organic matter ; solution of the fused mass in dilute acid ; and addition of excess of ammonia and filtration from alumina, phosphates, etc.5. 80 grms. of green petis wcre examined and found t o be absolutely free from copper. 6. The copper present in preserved peas is, therefore in actual combination, 7. The peas in stomachic digestion give up their copper t o solution. 8. Is THE COPPEE INTRODUCED INTO THE STOXACE ABSORBEI), OR WHAT BECOMES OF IT? On the 13th July, the authors of this paper took each a dose of 0.3 grains nf CuSO, 5H@, and examined the urine eliminated during the next 48 hours ; it was found to be entirely free from copper.The faxes secreted on the 30th by one of us, after taking 3 daily doses of *3 grain was examined, and was found t o yield abundant evidence of copper, forming indeed a very considerable proportion of a dose. Therefore, even if a part of the copper be absorbed into the system, another and pro6abZy the greater part passes out with the fseces.9. GENERAL CONSIDERATIONS AND CoNcLusroNs.-Inasmuch as copper is normally present in certain organs of the body as stated above, it must get there in the first place through an introduction into the stomach. How then can we reconcile this fact with the partial secrction, at least, of copper with the f w e s ? Apparently this is very easy of explanation. After gastric digestion and while the contents of the stomach are still acid, a part of the chyme is absorbed into the blood system, and this would seem to constitute the stage at which the copper is absorbed.The greater part, however, of the digested mass passes on through the pylorus, and undergoes a further change in the duodenum, whcre alkaline biliary fluid takes part in the process.The probable result as regards the is i t eliminated, and, if so, how ?104) TEE ANALYST. copper would be its precipitation as phosphate, which would not be changed in the intestines, but would be passed as such with the faeces. Now, if it be considered that ordinarily one person consumes only about two ounces of preserved peas at a meal, and that this quantity would contain only a fraction of a grain of cupric sulphate; and if it be further considered that only another fraction of this amount is ultimately absorbed into the blood system, it is impossible to defend the opinion of the prejudicial influence of such amount of copper upon health.This represents our conclusion based.upon the experiments we have described, and we think it probable that quite as much copper finds its way into the system through the handling of copper coins, the use of copper vessels in cooking operations, and in the consumption of pickles and such articles which are often prepare3 in copper vessels. At least we believe preserved peas are absolutely innocuous to health.10. OTHER CONFIRMATORY EVIDENCE OF THE I ~ ~ o c n o u s NATURE OF TRACES OF COPPER PRESENT IN FooDs.-In a prosecution case conducted before the Marlborough Street Police Court, on Monday, January 22, 1877. Dr. Pavy expressed the opinion that 0.31 of a grain of copper (sulphate 2) would not be injurious to health ; this opinion was unsupported by any evidence. In what has gone before we have supplied the evidence required, and these results are confirmed by, and confirmative of, other results recently communicated by M.Galippe to the French Academy of Sciences.s" He has found that the administration of large doses causes vomiting, but that the same compounds may be taken in increasing amounts for prolonged periods of time without the attendance of any painful symptoms.Galippe cites the experiments of Burq and Ducom, who fed ddgs with food that had been cooked and cooled in vessels made of copper, and previously exposed to the action of vinegar and salt ; the dogs mere not at all affected. Moreover, Galippe and his family have lived on food similarly prepared, without experiencing any poisonous effects. Dr. Redwood said he had been engaged in the prosecution of some dealers in preserved peas, which were contaminated with copper, and should be inclined to say that the case which had just been brought forward waB somewhat overproved.He referred to Some cases where the poisonous effects noticed mere without doubt due to copper. He was not prepared to say that a dealer was justified in supplying peas prepared with a substance which had an effect which was not necessary, and which was probably dangerous.If they were supplied, he thought they ought to be labelled '' peas preserved .rvith sulphate of copper." Mr. Siebold protested against the notion that because the copper was eliminated therefore no poisonous effect would he produced. He instanced iodide of potassium and other medicines as also being rapidly eliminated, but which had undoubted medicinal effects.Dr. Paul said the instances were not analogous. The copper passed through the system without being absorbed at all. Dr. Rome mentioned some instances from his own neighbourhood where streams, largely contaminated with copper, were indiscriminately drank by the population. I n one case there waa sufficient copper in the water to pay for its extraction; in another instance there was no less than sixteen grains to the imperial gallon. Nr. William Thomson had for a long period given t o a dog one grain of sulphate of copper per day in his food with no unfarourable results. Mr. Chipperfield said that in the neighbourhood of copper works, while vegetation was almost entirely destroyed, and copper could be distinctly tasted in the air, it was a fact that the residents were remarkable for longevity. He had found two grains of copper in each tin. * Compfus Iiemhs, April 9, 1877.