Paul Sabatier

Theories cannot claim to be indestructible. They are only the plough which the ploughman uses to draw his furrow and which he has every right to discard for another one, of improved design, after the harvest.

My own ideas on the mechanism of catalytic phenomena were very different from those at one time commonly held, ideas which I no doubt owed to the influence of the illustrious teacher who had guided my first steps in chemistry nearly twenty years before - I refer, of course, to Berthelot.

They also explained how the sensors can monitor the levels of acetone on people's breath, and this can be used to tell people who suffer from diabetes when their next insulin shot is due. This is a more discreet method than what is currently on the market.

In organic chemistry, we have learnt to derive from compounds containing only carbon and hydrogen, i.e. from the hydrocarbons, all other types of combinations, such as alcohols, aldehydes, ketones, acids, etc.