Abstract
The oxytocin content of a solution of oxytocin and ergometrine can be assayed with great accuracy by the chicken blood pressure method provided the rooster preparation is highly sensitive to oxytocin. The hormone can also be assayed with reasonable accuracy by measuring the response of the milk-ejection pressure in the mammary gland of the lactating rabbit. However, the rat uterus in vitro method yields erroneously high results due to the additional uterotonic effect of the ergometrine.