Noun
Jealousy.
The quality or state of being yellow; as, the yellowness of an orange.
Source: Webster's dictionaryLight which triggers this greenness response more than the yellowness or blueness of the other color opponent mechanism is called green. Source: Internet
However, on pages 191–192, he states "… I shall consider the cause of the yellowness which is so remarkable in this distemper, as to have given it the name of the Yellow Fever." Source: Internet