^2 INTRODUCTION TO SEXUAL PHYSIOLOGY 



septicaemia or puerperal fever may result. This condition is, of 

 course, abnormal and may be dangerous, requiring immediate 

 medical treatment. 



The normal discharge of blood and mucus from the interior 

 of the uterus lasts for about two weeks after parturition. It 

 is called the lochia and varies considerably in amount in different 

 individuals, any quantity between ten and fifty ounces being 

 normal. For the first few days after parturition the lochia 

 consists largely of blood, but it gradually becomes paler, and later 

 is composed almost entirely of mucus with which secretions from 

 the cervix and vagina mix. The occurrence of a persistent 

 discharge consisting largely of white corpuscles is abnormal 

 but not very uncommon. It indicates a local lesion which has 

 become infected. 



The involution of the uterus occurs rapidly in the first few 

 days after delivery, and then becomes more gradual, being 

 completed after from five to eight weeks. Thus the freshly 

 delivered uterus weighs about 1,000 grams or 2 lb. (as compared 

 with 30 grams for the virgin uterus), but a week after parturition 

 the organ weighs 500 grams, and at the end of the puerperium 

 as little as 60 grams or 2 oz. By the tenth day after parturition 

 the uterus becomes once more confined to the pelvis and cannot 

 be felt above the symphysis. The process of involution relates 

 chiefly to the muscle walls, the size of the cells being diminished, 

 while the vessels become more compressed. 



Lactation 



The structure of the mammary glands has been described in 

 a previous chapter. These glands, prior to conception, consist 

 of a few ducts in the immediate neighbourhood of the two 

 bilaterally situated nipples. In the human female it is not until 

 the beginning of pregnancy that they undergo any true growth, 

 such apparent hypertrophy as they appear to show at the 

 menstrual periods being confined mainly or entirely to an 

 augmented vascularisation and a slight increase in the number of 

 the ducts. After conception a rapid hypertrophy sets in, the 

 actual gland cells undergoing division and multiplication, and 

 new secretory alveoli are formed, while the nipples also develop 

 more fully. New alveoli are formed from those already in 



