Louis Pasteur, Conqueror of Disease

Yeast was alive and made of tiny living cells

The text clearly states that 'Pasteur became certain that yeast was alive, made up of tiny living cells.' He discovered that when these cells were healthy, the yeast worked well, but if diseased, both yeast and beer went wrong. Yeast is not a simple chemical compound, it works in bread-making too (not just beer), and while yeast contains microorganisms, Pasteur specifically identified it as living cells, not bacteria.

The bend in the long tube neck

Pasteur created a long narrow neck with 'a big bend in the middle.' This bend acted as a 'dust trap' - germs in dust could reach the bend but couldn't go further, so they settled there and couldn't infect the soup. The heating destroyed existing germs but wasn't the key feature preventing new ones. The glass type and bottle size weren't mentioned as important factors in the experiment.

On top of a high mountain

In Pasteur's air purity experiment, bottles opened 'on the top of a high mountain' had 'no germs in them at all.' Hotel bedroom bottles were completely mouldy (worst air), field bottles were mouldy but not as bad, showing mountain air was purest. This proved that germ concentration varies with location and that high altitudes have cleaner air. The laboratory isn't mentioned in this specific experiment.

50 to 60 degrees centigrade

The text specifically states that Pasteur showed 'by heating the wine, or milk, or whatever it might be to a temperature of 50 or 60 degrees centigrade, the germs were made harmless.' This moderate heating was sufficient to kill harmful germs without damaging the taste or quality of the product. Higher temperatures (70-80°C or 100°C) would be too hot and damage the product, while lower temperatures (30-40°C) wouldn't kill the germs effectively.