Louis Pasteur and Claude Bernard initiated a test of the idea of pasteurization by heating blood and urine in sealed flasks, 1862. The result of no observed fermentation or decomposition after 50 days supported the possibility of heating foods sufficiently to kill germs without significantly altering their chemical composition.
William Crookes in 1895 identified a new gas isolated by William Ramsay as helium (He, element 2, which had previously been observed as a line in the solar spectrum some 27 years earlier.)