[27] A cutaneous scarification by tuberculin which provokes local inflammatory redness on the scarified point in tuberculous subjects only.
The expedition was also intended to elucidate a few questions on the etiology of endemic plague in the Kirghiz steppes. When this intention became known, the Russian authorities desired to add to it a local mission on the study of plague epidemics in the steppes. Metchnikoff, who was chiefly concerned with the question of tuberculosis, was only able to draw up a plan of work for the Russian mission and to start it going in one of the plague centres.
The Pasteur Institute expeditionary party comprised, besides Metchnikoff, MM. Burnet, Salimbeni, and Iamanouchi. They were joined at Moscow by Drs. Tarassevitch and Choukevitch, and at Astrakhan by the physicians of the Russian plague mission. The Institut Pasteur party left Paris on May 14, 1911, full of spirits; Metchnikoff, eager to make the journey pleasant for his companions, was doing the honours of his country to the best of his ability; he fully succeeded, owing to the warm welcome and liberal hospitality which they received in Russia, where every one tried to contribute not only to the success of the expedition but to the comfort and pleasure of its members. The latter, indeed, preserved a most pleasant recollection of this journey, and, in later years, always spoke of it with pleasure.
Navigation on the Volga from Nijni Novgorod to Astrakhan was full of peculiar charm. That five days' journey was one of the rare periods of complete rest in Metchnikoff's life. He indulged in the _dolce far niente_ as he watched the peaceful landscape on the passing banks. The Volga, then in flood, covered immense spaces. Here and there, whole forests emerged from the river which reflected them as in an enchanted dream. From time to time, little isolated villages appeared with the gilt cupola of a church or a monastery, then meadows, forests, steep cliffs, or gentle slopes down to the river. What poetry, what grandeur in simplicity! As in a kaleidoscope, types of varied populations and pictures of local customs followed upon each other.
Along the banks now and then were seen processions of pilgrims. Their humble, gray, stooping figures breathed deep faith and resignation. Sometimes popular songs arose from the Volga, sad, expressive, soul-penetrating chants.