Assertion: solution | /r/MadeOf | potassium
Facets:
value: in a definite proportion
type: OTHER
Source sentences:
text: Ringer's solution is named after Sydney Ringer, who in 1882–1885 determined that a solution perfusing a frog's heart must contain sodium, potassium and calcium salts in a definite proportion if the heart is to be kept beating for long.