Meanings of rarify in English

Nature, however refined and cultivated the man, or rarified his atmosphere, sees to this.

Who participate in that joy which dissolves and rarifies man to the essence of heaven?

If the heat rarifies the blood and juices, while the cold air constringes the fibres, and obstructs the perspiration, inflammatory disorders must ensue.

How do they dwell on the principle of virtue, and turn it in every metaphysical light, until their philosophy rarifies it to nothing!