PARTURITION— PUERPERIUM— LACTATION 8i 



ever been regarded as complete or satisfactory. As to why 

 the uterus, after having borne its burden so tolerantly and for so 

 long, should suddenly be thrown into violent contraction, has 

 remained a mystery, at any rate until quite recently, but, as we 

 shall see later, there is now evidence that the cause is to be 

 sought for in the rhythm of the endocrine activities of the ovary. 

 It has been known that even the virgin uterus undergoes faint 

 contractions at more or less regular intervals, and that these 

 may increase in force at the periods of menstruation, when 

 the ovaries are more active. Moreover, recent investigation 

 has shown that the ovarian influence upon the uterus is inhibited 

 during pregnancy when the corpus luteum is a dominating factor, 

 but that as this structure declines the uterine contractions gain 

 in force, the expulsion of the foetus being the culminating effect. 

 It would appear probable that the ovary does not act directly 

 upon the uterus but rather through the intermediation of the 

 pituitary gland. This is a matter to which we shall return in 

 the next chapter when considering the ovary as an organ of 

 internal secretion. 



The Puerperium 



The puerperium or " lying-in " period usually lasts from about 

 ten days to three or four weeks. It is the time when the lacerated 

 uterine mucosa becomes healed, and the whole uterus undergoes 

 rapid involution, but it never regresses to the size of the virgin 

 uterus. It is important that the lying-in period should not be 

 imprudently shortened, as, apart from the danger of " prolapsus 

 uteri," which may occur as a result of undue exertion after delivery, 

 the whole body is in need of rest and recuperation. It is to be 

 noted, however, that among labouring women and others who 

 are exceptionally healthy and strong, the lying-in period may 

 be considerably shortened, whilst among uncivilised races there 

 is often hardly any puerperium at all. Still more so is this true 

 of the lower mammals. 



There is generally a slight rise of temperature on the third day 

 after labour, but this is merely indicative of some metabolic 

 disturbance of a febrile nature on the part of the mother, and 

 should very soon subside. If, however, owing to want of 

 proper cleanliness the bleeding uterine mucosa becomes infected, 

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