It is now many years since I inhabited the “students’ quarter” in the gay city, and rented a couple of little rooms in an hotel meuble not far from the gardens of the Luxembourg.  Medical students are never rich, and I was no exception to the rule, though, compared with many of my associates, my pecuniary position was one of enviable affluence.  I had a library of my own, I drank wine at a franc the litre, and occasionally smoked cigars.  My little apartment overlooked a wide street busy with incessant traffic, and on warm evenings, after returning from dinner at the restaurant round the corner, it was my habit to throw open my window-casement and lean out to inhale the fresh cool air of the coming night, and to watch the crowds of foot-passengers and vehicles going and coming like swarms of ants along the paved street below.

On a certain lovely July evening towards the close of my student career, I took up my favourite position as usual, luxuriating in the fumes of my cigarette and in that sweetest of mental enjoyments, absolute idleness, carried at the cost of hard and long-continued toil.  The sun had but just gone down, the sky was brilliant with pink lights and mellow tints of golden green blending with the blue of the deep vault overhead, scores of swift-darting birds were wheeling about in the still air, uttering sharp clear cries, as though calling one another to rest below, women stood at their house-doors gossiping with their neighbours; peals of laughter and the incessant chatter of feminine voices mingled with the din of horses’ hoofs on the hard road and with the never-ending jingle of the harness-bells.

Gazing lazily down into the street, my attention was suddenly arrested by the singular appearance and behavior of an odd-looking brown dog, which seemed to be seeking someone among the hurrying crowds and rattling carts.  Half-a-dozen times he ran up the street and disappeared from view, only to retrace his steps, each time with increasing agitation and eagerness of manner.  I saw him cross the street again and again, scan the faces of the passersby, dash up the various turnings and come panting back, his tongue, his tail drooping; one could even fancy there were tears in his eyes.  At length, exhausted or despairing, he crossed the street for the last time and sat down on the doorstep of the house I inhabited, the picture of grief and dismay.  He was lost!  Now I had not served my five years’ apprenticeship to medical science in Paris without becoming intimate with the horrible secrets of physiological laboratories.  I knew that a lost dog in Paris, if not handsome, and valuable to sell as a pet, runs a terrible chance of falling directly or indirectly into the hands of vivisecting professors, and dying a death of torture.  He may be picked up by an employee engaged in the search for fitting victims, and so handed over to immediate martyrdom, or he may be hurried off to