In some respects this sort of protection is even more necessary, as well as more deficient, in regard to _the falsification of drugs_. The College of Physicians and the Apothecaries’ Company are supposed to exercise supervision in the matter; so that at least its necessity is recognised by the law. The security thus afforded is, in practice, null. It is notorious in my profession that there are not many simple drugs, and still fewer compound preparations, on the standard strength of which we can reckon. It is notorious that some important medicines are so often falsified in the market, and others so often mis-made in the laboratory, that we are robbed of all certainty in their employment. Iodide of potassium--an invaluable specific, may be shammed to half its weight with the carbonate of potash. Scammony, one of our best purgatives, is rare without chalk or starch, weakening it, perhaps, to half the intention of the giver. Cod-liver oil may have come from seals or from olives. The two or three drops of prussic acid that we would give for a dose may be nearly twice as strong at one chemist’s as at another’s. The quantity of laudanum equivalent to a grain of opium being, theoretically, 19 minims; we may practically find this grain, it is said, in 4.5 minims, or in 34.5. And my colleague, Dr. R. D. Thomson, who has much experience in these matters, tells me that of calamine--not indeed an important agent, but still an article of our pharmacopœia--purporting daily to be sold at every druggist’s shop, there has not for years, he believes, existed a specimen in the market.[5] [5] Dr. Thomson tells me that he has known white precipitate of mercury sold in hundred-weights as calomel, and in one case (he believes by accident or ignorance) as trisnitrate of bismuth. In my text I have endeavoured to adduce such illustrations as I suppose to be most notorious; but I may refer the reader to various interesting papers published, through the last two or three years, in the LANCET (_Analytical Sanitary Commission_) from one of which I quote the astounding instance, given above, of variations in the strength of laudanum. Mr. Thomas Taylor, of Vere Street, informs me that, whereas an ounce of laudanum should contain about four grains of morphia, he finds the actual quantity varying in different specimens from two grains to six; and that in two specimens of solid opium, outwardly alike and supposed to be of equal quality, he has found the per centage of morphia to vary from 3½ to 10. It requires little instruction in medicine to appreciate these facts.