Whilst he was preparing this vintage tour, which he intended to make with three “Normaliens,” Duclaux, Gernez and Lechartier, the three heterogenists, Pouchet, Joly and Musset, proposed to use that same time in fighting Pasteur on his own ground. They started from Bagnères-de-Luchon followed by several guides and taking with them all kinds of provisions and some little glass flasks with a slender pointed neck. They crossed the pass of Venasque without incident, and decided to go further, to the Rencluse. Some isard-stalkers having come towards the strange-looking party, they were signalled away; even the guides were invited to stand aside. It was necessary to prevent any dusts from reaching the bulbs, which were thus opened at 8 p.m. at a height of 2,083 metres. But eighty-three metres higher than the Montanvert did not seem to them enough, they wished to go higher. “We shall sleep on the mountain,” said the three scientists. Fatigue and bitter cold, they withstood everything with the courage inspired by a problem to solve. The next morning they climbed across that rocky chaos, and at last reached the foot of one of the greatest glaciers of the Maladetta, 3,000 metres above the sea-level. “A very deep narrow crevasse,” says Pouchet, “seemed to us the most suitable place for our experiments.” Four phials (filled with a decoction of hay) were opened and sealed again with precautions that Pouchet considered as exaggerated. Pouchet, in his merely scientific report, does not relate the return journey, yet more perilous than the ascent. At one of the most dangerous places, Joly slipped, and would have rolled into a precipice, but for the strength and presence of mind of one of the guides. All three at last came back to Luchon, forgetful of dangers run, and glorying at having reached 1,000 metres higher than Pasteur. They triumphed when they saw alteration in their flasks! “Therefore,” said Pouchet, “the air of the Maladetta, and of high mountains in general, is not incapable of producing alteration in an eminently putrescible liquor; therefore heterogenia or the production of a new being devoid of parents, but formed at the expense of ambient organic matter, is for us a reality.”