1. In the venous blood of a patient with Vaquez' disease normal values were found for the oxygen unsaturation (reduced hemoglobin), although the total hemoglobin and oxygen capacity were abnormally high. The carbon dioxide content was normal.
2. The color of the skin and mucous membranes of this patient was more reddish than blue.
3. It is proposed to call the color of the skin in polycythemic patients erythrosis in order to distinguish the condition from cyanosis.