258 



Human Physiology. 



of gestation and lactation from the beginning of pregnancy 

 until the child is weaned the menses are suspended. 



It is upon the womb, and the embryo it protects and 

 nourishes, that the nervous power, the most interior life of 

 the mother, is chiefly expended ; and she needs every atom of 

 that life for the wonderful processes there to be accomplished. 

 The womb, or uterus, as shown in Fig. 59, p. 252, is shaped like 

 a flattened pear, with its neck downward, opening into the 

 vagina, and is scarcely larger than a small hen's egg. When 

 the germ becomes fecundated at or before its entrance into 

 the womb, as it passes out of the Fallopian tube, there is 

 a nervous shock of which women are sometimes conscious. 

 The womb suddenly expands ; its arteries enlarge and are filled 



with blood ; an exudation 

 from the inner or mucous 

 surface of the womb forms 

 a strong rough membrane, 

 which the germ pushes be- 

 fore it, so that it forms a 

 double envelopment for its 

 protection. A clot or plug 

 is formed to close the 

 mouth of the womb. A 

 mass of blood-vessels and 

 nerves forms upon the in- 

 side of the womb, called 

 the placenta ; a double 

 organ, with two complete 

 sets of vessels, one set 

 communicating with the 

 Fig. 63-FcExus IN UTERO.* mother, through the walls, 



arteries, and veins of the womb ; the other set with the child, 



* Sectional view of the uterus with the ovum ; the cervix uteri is plugged 

 up with a gelatinous mass, a. The decidua vera, c, sends a process, <r 2 , into 



