What did joseph black and his student daniel rutherford study that impacted modern stoichiometry?

Daniel Rutherford's chemistry teacher was originally William Karen, and in 1766 Karen succeeded Robert White as Dean of the Faculty of Medicine, and Joseph Blake took over as a professor of chemistry at Karen. Blake in the study of the nature of carbon dioxide, found in the gas can not burn in this gas. He gave the question to his students, and in his doctoral thesis submitted in 1722, Daniel Rutherford found that carbon dioxide can be obtained by calcining limestone or by limestone and acid reaction and can be absorbed with caustic soda solution.Then Daniel Rutherford put animals and burning candles in a sealed container, and found that the animals were still dead and the candles were extinguished, and a large part of the gas was still present in the container. He absorbed some of the carbon dioxide with caustic soda and left some gas that could not support breathing, so he called the gas "harmful gas" (ie, nitrogen). As Rutherford and Blake all believe that the phlogiston said that burning is a combustible material release of phlogiston, the surrounding gas to accept the process of phlogiston, and the gas in the gas has been saturated, and therefore do not support the burning, so called "fuel gas" TheAfter taking a doctorate in medicine, Daniel Rutherford traveled to France and Italy, and returned to Edinburgh for medical practice in 1775. In 1777 he was elected a member of the Royal Medical Association, and in 1778 read out about the active gas (oxygen) Of the paper. In 1786 he succeeded John Hugh as the professor of botany at the University of Edinburgh and the manager of the Edinburgh Royal Botanical Garden.

What? i don’t understand