"Allow me to take one of your clean specimen slides," observed Mr. Tertius, picking up a square of highly polished glass. "There! I place this slide here and upon it I deposit this sandwich. Now, my dear Cox-Raythwaite, favour me by examining the sandwich even more closely than you did the glass--if necessary." But the Professor shook his head. He clapped Mr. Tertius on the shoulder. "Excellent!" he exclaimed. "Good! Pooh!--no need for care there. The thing's as plain as--as I am. Good, Tertius, good!" "You see it?" said Mr. Tertius, delightedly. "See it! Good Lord, why, who could help see it?" answered the Professor. "Needs no great amount of care or perception to see that, as I said. Of course, I see it. Glad you did, too!" "But we must take the greatest care of it," urged Mr. Tertius. "The most particular care. That's why I came to you. Now, what can we do? How preserve this sandwich--just as it is?" "Nothing easier," replied the Professor. "We'll soon fix that. We'll put it in such safety that it will still be a fresh thing if it remains untouched until London Bridge falls down from sheer decay." He moved off to another part of the laboratory, and presently returned with two objects, one oblong and shallow, the other deep and square, which on being set down before Mr. Tertius proved to be glass boxes, wonderfully and delicately made, with removable lids that fitted into perfectly adjusted grooves. "There, my dear fellow," he said. "Presently I will deposit the glass in that, and the sandwich in this. Then I shall adjust and seal the lids in such a fashion that no air can enter these little chambers. Then through those tiny orifices I shall extract whatever air is in them--to the most infinitesimal remnant of it. Then I shall seal those orifices--and there you are. Whoever wants to see that sandwich or that glass will find both a year hence--ten years hence--a century hence!--in precisely the same condition in which we now see them. And that reminds me," he continued, as he turned away to his desk and picked up his pipe, "that reminds me, Tertius--what are you going to do about these things being seen? They'll have to be seen, you know. Have you thought of the police--the detectives?" "I have certainly thought of both," replied Mr. Tertius. "But--I think not yet, in either case. I think one had better await the result of the inquest. Something may come out, you know." "Coroners and juries," observed the Professor oracularly, "are good at finding the obvious. Whether they get at the mysteries and the secrets----" "Just so--just so!" said Mr. Tertius. "I quite apprehend you. All the same, I think we will see what is put before the coroner. Now, what point suggests itself to you, Cox-Raythwaite?" "One in particular," answered the Professor. "Whatever medical evidence is called ought to show without reasonable doubt what time Herapath actually met his death." "Quite so," said Mr. Tertius gravely. "If that's once established----"