IODINE TEARS

image source- wiki commons

This is from an old detective story entitled "The Sorceress of the Strand- V. The Bloodstone.", found in "The Strand" Magazine, 1903. Apparently there were six parts in the Sorceress Tales.... More information can be found here:

http://prettysinister.blogspot.com

A synopsis: Lady Bouverie(Violet) is being framed for the theft of a treasured Persian Bloodstone. Madam Sara(the villian) dresses up and acts the part of a distraught Violet handing something over to a masked man and then dropping a handkerchief during a midnight liaison in a moonlit garden...

"He", referred to below, is Eric Vandeleur, Doctor, Madam Sara's arch-nemesis and, conveniently, an old family friend of Lady Bouvier's(and her treating physician)! "I", referred to below, is the detective, Dixon Druce, also conveniently an old family friend of Violet's.

How fortuitous that the major players would all end up in the mansion at the same time... !!

you can read the story in it's entirety here, it's actually quite entertaining:

The Sorceress in the Strand, Part V

Vandeleur's expression suddenly changed. He was regarding Lady Bouverie with a steady look; he then took up the handkerchief which we had found, examined it carefully, and laid it down again.

"Have you been taking the medicine I ordered you, Lady Bouverie ?" was his remark.

"I have," she replied

image source- wiki commons

"To-day?"

"Yes; three times."

"Will someone give me a large, clean sheet of white paper?"

I found one at once and brought it to him. He carefully rolled the handkerchief in it, drew out his stylograph, and wrote on the package :—

'' Handkerchief found by Sir John Bouverie and Mr. Druce at 12:40 a.m."

He then asked Lady Bouverie for the one which she had in her pocket; this was almost as wet as the one I had picked up. He put it in another packet, writing also upon the paper:—

"Handkerchief given to me by Lady Bouverie at 3:20 a.m."

Then, drawing the inspector aside, he whispered a few words to him which brought an exclamation of surprise from that officer.

"Now," he said, turning to Sir John, "I have done my business here for the present. I mean to return to London at once in my motorcar, and I shall take Mr. Druce with me. The inspector here has given me leave to take also these two handkerchiefs, on which I trust important evidence may hang."

He drew out his watch.

"It is now nearly half-past three," he said. "I shall reach my house at 4.30; the examination will take fifteen minutes; the result will be dispatched from Westminster police-station to the station here by telegram. You should receive it, Sir John, by 5.30, and I trust," he added, taking Lady Bouverie's hand, "it will mean your release, for that you are guilty I do not for a moment believe. In the meantime the police will remain here."

He caught-my arm, and two minutes later we were rushing through the night towards London.

"My dear fellow," I gasped, "explain yourself, for Heaven's sake. Is Violet innocent?"

"Wonderful luck," was his enigmatical answer. "I fancy Sara has over-acted this piece."

"You can find the bloodstone?"

"That I cannot tell you; my business is to clear Lady Bouverie. Don't talk, or we shall be wrecked."

He did not vouchsafe another remark till we stood together in his room, but he had driven the car like a madman.
He then drew out the two packets containing the handkerchiefs and began to make rapid chemical preparations.

"Now, listen," he said. "You know I am treating Lady Bouverie. The medicine I have been giving her happens to contain large doses of iodide of potassium. You may not be aware of it, but the drug is eliminated very largely by all the mucous membranes, and the lachrymal gland, which secretes the tears, plays a prominent part in this process. The sobbing female whom you are prepared to swear on oath was Lady Bouverie at the rendezvous by the summer-house dropped a handkerchief—this one." He laid his finger on the first of the two packets. "Now, if that woman was really Lady Bouverie, by analysis of the handkerchief I shall find, by means of a delicate test, distinct traces of iodine on it. If, however, it was not Lady Bouverie, but someone disguised with the utmost skill of an actress to represent her, not only physically, but with all the emotions of a distracted and guilty woman, even to the sobs and tears—then we shall not find iodine on the analysis of this handkerchief."

My jaw dropped as the meaning of his words broke upon me.

"Before testing, I will complete my little hypothesis by suggesting that the note, evidently thrown in your way, was to decoy you to be a witness of the scene, and that the handkerchief taken from Lady Bouverie's room and marked with her initials was intended to be the finishing touch in the chain of evidence against her. Now we will come to facts, and for all our sakes let us hope that my little theory is correct."
He set to work rapidly. At the end of some operations lasting several minutes he held up a test tube containing a clear solution.

"Now," he said, opening a bottle containing an opalescent liquid; "guilty or not guilty?"

He added a few drops from the bottle to the test tube. A long, deep chuckle came from his broad chest.

"Not a trace of it," he said. "Now for the handkerchief which I took from Lady Bouverie for a check experiment."

He added a few of the same drops to another tube. A bright violet colour spread through the liquid.

"There's iodine in that, you see. Not guilty, Druce."

A shout burst from my lips.

"Hush, my dear chap!" he pleaded. "Yes, it is very pretty. I am quite proud."

-I am impressed that the authors of this turn of the century detective story knew that iodine is eliminated, in part, by the lachrymal glands!

-and that they knew of the iodine starch test :)

The Evil Madam Sara posing as Lady Violet in the Moonlit Garden...