Note F — Chapter VIII · THE FUNCTIONS OF THE FEMALE GENITAL ORGANS
Reading edition
This monthly periodicity is attributed by some authorities to cosmic influences (the new moon and full moon). But since other vital processes also show a certain undulatory increase and decrease in strength (e. c. the systole and diastole of the heart), it is more probable that the periodicity of ovulation is due to an undulatory motion, where the length of the wave is about four weeks.