The data gathered among the Kalmuk population justified Metchnikoff's hypothesis. In the centre of the steppes, where the Kalmuks were still isolated, tuberculosis was completely unknown; diagnosis reactions were negative. They became positive more and more frequently as we came nearer the periphery of the steppes and the Russian population. The extreme sensitiveness of the Kalmuks must therefore depend on the fact that they have suffered no natural vaccination in the steppes, which would support the idea that some natural vaccine exists amongst us. Metchnikoff therefore concluded that he might direct ulterior researches towards the quest of natural tuberculous vaccines. Such were the scientific results of the expedition. Apart from that, the journey to Russia had a strong personal influence on Metchnikoff. He had formerly left his country under the impression of the fatal error committed by the revolutionaries in killing Alexander II., an error which had led to a protracted reaction. He had therefore remained very sceptical concerning the Russian revolutionary movement; he thought that the necessary reforms might come from a Government evolution. But, during his sojourn in Russia, he was able to appreciate events which modified his ideas to a great extent. He was impressed by the contrast between the progressive aspirations of the "intellectuals" and the inertia or noxious activity of the rulers. The policy of Casso, the Minister of Public Instruction, who ordered regular raids in the universities, the persecution of Poles and Jews, the encouragement of the "black band" obscurantism, giving plenary powers to creatures of darkness like Rasputin and his peers, all these things excited indignation in a man who placed the free development of human culture above everything. He thus ceased to count upon the progressive evolution of a Government which was incapable of solving the complicated problems of Russian life, and henceforward thought that those problems would be solved by the "intellectuals" apart from the Government and in opposition to it. CHAPTER XXXII Further researches on the intestinal flora--_Forty Years' Search for a Rational Conception of Life._ Since Metchnikoff had conceived the idea that a considerable part was played in human life by the intestinal flora, his thoughts had centred around a study which he thought profitable: that of the influence of intestinal microbes on the normal and on the pathological organism.