Serum Chlorides in Pregnant Mice

Abstract

DURING previous work on the serum chlorides of agouti and non-agouti mice, it was noted that pregnant mice usually gave lower results than non-pregnant. This has been investigated, using the technique previously described¹. Estimations were made at the tenth day of pregnancy, as judged by the date of the vaginal plug and checked by the age of the embryos². It is considered that the limits of departure from this date did not exceed 24 hr. All females were placed with the male at the age of eight weeks. They did not all become pregnant on the same day, due to variations in their œstrus cycles, so that there were differences in the ages at which the estimations were made, the greatest being four days. No relationship between these differences in age, either in pregnant or non-pregnant mice, and the chloride levels has been found. Controls were non-pregnant mice from the same litters at the same ages.