THE DEVELOPMENT OF THE EMBRYO 1139 



of these gave birth to a child which was subsequently suckled by either 

 with equally beneficial, results. 



The enlarging uterus also inflicts certain spatial restrictions upon the neighbor- 

 ing pelvic and abdominal organs. Since these changes are effected chiefly by its 

 fundus, whereas the cervix tends to retain its previous size, a rather acute angle 

 is finally formed between these parts, which is augmented stillfurther as the fundus 

 progresses upward beyond the boundaries of the pelvis. At the fourth month the 

 upper border of the latter lies opposite a horizontal line drawn midway between the 

 umbilicus and the symphysis pubis, at the end of the sixth month opposite the 

 umbilicus, and at the end of 9 months almost opposite the ensiform cartilage. The 

 intestines are forced into the lateral extents of the abdominal cavity, so that the 

 anterior wall of the uterus comes to rest against the anterior wall of the abdomen. 

 The linea alba is broad and sharply outlined by its glistening white color. It need 

 scarcely be emphasized that these encroachments are responsible for a whole series 

 of far-reaching reflex actions. 



Among the latter might be mentioned the vomiting of pregnancy, minor dis- 

 orders of digestion, constipation, and stagnation phenomena in the biliary passages. ^ 

 The kidneys may be affected directly by pressure, as well as indirectly in conse- 

 quence of various disturbances of metabolism. The heart is displaced and its area 

 of dulness increased. The latter change has given rise to the statement that this 

 organ undergoes at this time a mild hypertrophy. ^ The pulse rate is not materially 

 increased, whereas, the pulse-pressure and total work of the heart are augmented 

 in a considerable measure. The respiratory movements are'somewhat hindered, 

 owing to the upward displacement of the diaphragm, but the total interchange of 

 the gases is rather increased. This is made possible by a broadening out of the 

 thorax. A moderate hypertrophy of the thyroid and parathyroid bodies is not 

 uncommon even during normal pregnancy,^ and a similar change may be displayed 

 by the hypophysis and the cortex of the adrenal glands.^ Peculiar yellowish 

 discolorations, the so-called chloasmas, appear in different regions of the skin. 

 The pregnant woman also displays mild mental disturbances which are associated 

 with an increased irritability, of the entire nervous system. Thus, she may 

 crave for the most unusual articles of food and suffer from mental depression 

 and all sorts of imaginary evils. For the neuropathic woman, this period is one of 

 danger, because these mild and functional psychoses may finaily develop into a 

 permanent or true psychosis. 



In general, however, it cannot be doubted that pregnancy improves 

 the condition of the woman, and while this change may not be appar- 

 ent during the first few months, it certainly makes itself felt later on.^ 

 The initial period of fatigue, lassitude and mental depression appears 

 to be associated with the rapid depletion of her energy by the rapidly 

 growing embryo. Later on, however, when a more stable equilibrium 

 has been established by the development of greater storative qualities, 

 her health improves perceptibly. This is especially true of her power 

 of retaining nitrogen and constructing proteid tissue, which in turn 

 leads to an increase in her weight and a decrease in the nitrogenous 

 content of her urine from its previous level of about 90 per cent, to 



1 Opitz, Zeitschr, flir Geburtshilfe und Gynec, Ixxii, 1913, 351, and Hofbauer, 

 ibid., Ixi, 1908, 200. 



2 Jaschke, Archiv fur Gynec, xciii, 1911, 809. 



^ Seitz, Pnnere Sekretion und Schwangerschaft, Leipzig, 1913. 



" Mayer, Archiv fiir Gynec, xc, 1910, 600. 



^ Bar, Legons, de path, obstetricale, Paris, 1907. 



