“Ptomaines are chemical compounds of an alkaloidal nature formed in protein substances during putrefaction.  They are purely chemical bodies and differ from the toxins.  There are also what are called leucomaines, formed in living tissues, and when not given off by the body they produce auto-intoxication.

“There are more than three score ptomaines, and half of them are poisonous.  In fact, illness due to eating infected foods is much more common than is generally supposed.  Often there is only one case in a number of those eating the food, due merely to that person’s inability to throw off the poison.  Such cases are difficult to distinguish.  They are usually supposed to be gastro-enteritis.  Ptomaines, as their name shows, are found in dead bodies.  They are found in all dead matter after a time, whether it is decayed food or a decaying corpse.

“No general reaction is known by which the ptomaines can be distinguished from the vegetable alkaloids.  But we know that animal alkaloids always develop either as a result of decay of food or of the decay of the body itself.”

At one stroke Kennedy had reopened the closed case and had placed the experts at sea.

“I find that there is an animal conine as well as the true conine,” he hammered out.  “The truth of this matter is that the experts have confounded vegetable conine with cadaveric conine.  That raises an interesting question.  Assuming the presence of conine, where did it come from?”

He paused and began a new line of attack.  “As the use of canned goods becomes more and more extensive, ptomaine poisoning is more frequent.  In canning, the cans are heated.  They are composed of thin sheets of iron coated with tin, the seams pressed and soldered with a thin line of solder.  They are filled with cooked food, sterilised, and closed.  The bacteria are usually all killed, but now and then, the apparatus does not work, and they develop in the can.  That results in a ’blown can’—­the ends bulge a little bit.  On opening, a gas escapes, the food has a bad odour and a bad taste.  Sometimes people say that the tin and lead poison them; in practically all cases the poisoning is of bacterial, not metallic, origin.  Mr. Godwin may have died of poisoning, probably did.  But it was ptomaine poisoning.  The blown cans which I have discovered would indicate that.”

I was following him closely, yet though this seemed to explain a part of the case, it was far from explaining all.

“Then followed,” he hurried on, “the development of the usual ptomaines in the body itself.  These, I may say, had no relation to the cause of death itself.  The putrefactive germs began their attack.  Whatever there may have been in the body before, certainly they produced a cadaveric ptomaine conine.  For many animal tissues and fluids, especially if somewhat decomposed, yield not infrequently compounds of an oily nature with a mousey odour, fuming with hydrochloric acid and in short, acting just like conine.  There is ample evidence, I have found, that conine or a substance possessing most, if not all, of its properties is at times actually produced in animal tissues by decomposition.  And the fact is, I believe, that a number of cases have arisen, in which the poisonous alkaloid was at first supposed to have been discovered which were really mistakes.”