In speaking of the principle of irritability he expresses himself in the following manner. “I think that the oxygen is absorbed by the blood, and that the venous blood is oxygenated in the lungs during respiration. The most celebrated naturalists and chemists are of a different opinion: they think that the oxygen does not combine with the venous blood. According to them, this last loses carbon and hydrogen, and recovers the bright colour natural to it, without absorbing any thing from the atmosphere.... After having a long time attended the phenomena of respiration, and made many experiments upon this subject, I think it may be concluded that one part of the oxygen of the vital air combines with the venous blood, of which it changes the black colour, and makes it vermilion;[67] the second part of the oxygen unites with the carbon contained in the carbonic-hydrogen gas, which exhales from the venous blood, and forms carbonic acid air; a third part unites with the carbon of the mucus, contained in great quantities in the lungs, and which is continually decomposing; this part also forms carbonic acid air; a fourth part of the oxygen combines with the hydrogen of the blood to form water.” [67] Here Dr. Beddoes, from whose publication this account of Girtanner’s memoir is taken, has the following note: “Dr. Goodwyn had proved this before. Could Dr. Girtanner be ignorant of his experiments?” In justice to myself, however, I must observe that this very doctrine had been published in the Encyclopædia Britannica long before either Dr. Goodwyn or Dr. Girtanner had made any experiments on the subject. It may still be seen under the article BLOOD, and reasons are there given for supposing that only one part of the oxygen, viz, the elastic part, can be absorbed.