The largest amount of tin I ever detected in actual solution in food was in some canned soup, containing a good deal of lemon juice.  It amounted to only three-hundredths of a grain in a half pint of the soup as sent to table.  Now, Christison says that quantities of 18 to 44 grains of the very soluble chloride of tin were required to kill dogs in from one to four days.  Orfila says that several persons on one occasion dressed their dinner with chloride of tin, mistaking it for salt.  One person would thus take not less than 20 to 30 grains of this soluble compound of tin.  Yet only a little gastric and bowel disturbance followed, and from this all recovered in a few days.  Pereira says that the dose of chloride of tin as an antispasmodic and stimulant is from 1/16 to 1/2 a grain repeated two or three times daily.  Probably no article of canned food, not even the most acid fruit, if in a condition in which it can be eaten, has ever contained, in an ordinary table portion, as much of a soluble salt of tin as would amount to a harmless or useful medicinal dose.

Metallic particles of tin are without any effect on man.  A thousand times the quantity ever found in a can of tinned food would do no harm.

Food as acid as say ordinary pickles would dissolve tin.  Some manufacturers once proposed using tin stoppers to their bottles of pickles.  But the tin was slowly dissolved by the acid of the vinegar.  These pickles, however, had a distinctly nasty “metallic” flavor.  The idea was abandoned.  Probably any article of food containing enough tin to disagree with the system would be too nasty to eat.  Purchasers of food may rest assured that the action taken by this firm would be that usually followed.  It is not to the interest of manufacturers or other venders to offend the senses of purchasers, still less to do them actual harm, even if no higher motive comes into force.

In the early days of canning, it is just possible that the use of “spirits of salt” in soldering may have resulted in the presence of a little stannous, plumbous, or other chloride in canned food; but such a fault would soon be detected and corrected, and as a matter of fact, resin-soldering is to my knowledge more generally employed—­indeed, for anything I know to the contrary, is exclusively employed—­in canning food.  Any resin that trained access would be perfectly harmless.  It is just possible, also, that formerly the tin itself may have contained lead, but I have not found any lead in the sheet tin used for canning of late years.

In conclusion:  1.  I have never been able to satisfy myself that a can of ordinary tinned food contains even a useful medicinal dose of such a true soluble compound of tin as is likely to have any effect on man. 2.  As for the metal itself, that is the filings or actual metallic particles or fragments, one ounce is a common dose as a vermifuge; harmless even in that quantity to man, and not always