“No.  And now let us look at the other wound.  Will you note down the description?” He handed me his notebook, and I wrote down as he dictated:  “A clean-punched circular hole in skull, an inch behind and above margin of left ear—­diameter, an inch and seven-sixteenths; starred fracture of parietal bone; membranes perforated, and brain entered deeply; ragged scalp-wound, extending forward to margin of left orbit; fragments of gauze and sequins in edges of wound.  That will do for the present.  Dr. Morton will give us further details if we want them.”

He pocketed his callipers and rule, drew from the bruised scalp one or two loose hairs, which he placed in the envelope with the sequins, and, having looked over the body for other wounds or bruises (of which there were none), replaced the sheet, and prepared to depart.

As we walked away from the mortuary, Thorndyke was silent and deeply thoughtful, and I gathered that he was piecing together the facts that he had acquired.  At length Mr. Stopford, who had several times looked at him curiously, said: 

“The post-mortem will take place at three, and it is now only half-past eleven.  What would you like to do next?”

Thorndyke, who, in spite of his mental preoccupation, had been looking about him in his usual keen, attentive way, halted suddenly.

“Your reference to the post-mortem,” said he, “reminds me that I forgot to put the ox-gall into my case.”

“Ox-gall!” I exclaimed, endeavouring vainly to connect this substance with the technique of the pathologist.  “What were you going to do with—­”

But here I broke off, remembering my friend’s dislike of any discussion of his methods before strangers.

“I suppose,” he continued, “there would hardly be an artist’s colourman in a place of this size?”

“I should think not,” said Stopford.  “But couldn’t you got the stuff from a butcher?  There’s a shop just across the road.”

“So there is,” agreed Thorndyke, who had already observed the shop.  “The gall ought, of course, to be prepared, but we can filter it ourselves—­that is, if the butcher has any.  We will try him, at any rate.”

He crossed the road towards the shop, over which the name “Felton” appeared in gilt lettering, and, addressing himself to the proprietor, who stood at the door, introduced himself and explained his wants.

“Ox-gall?” said the butcher.  “No, sir, I haven’t any just now; but I am having a beast killed this afternoon, and I can let you have some then.  In fact,” he added, after a pause, “as the matter is of importance, I can have one killed at once if you wish it.”

“That is very kind of you,” said Thorndyke, “and it would greatly oblige me.  Is the beast perfectly healthy?”

“They’re in splendid condition, sir.  I picked them out of the herd myself.  But you shall see them—­ay, and choose the one that you’d like killed.”