REPRODUCTION. 477 



The uterine glands arc thought by some to afford a nutritive secretion to the 

 sinuses, and to the amniotic liquid has been ascribed a nutritive function. 

 Theoretically, these various means are not impossible, but true placental diffu- 

 sion must be regarded as the chief principle at work. The result is that the 

 mother relieves the child of all the labor of nutrition except that connected 

 directly with the hitter's own cellular and protoplasmic metabolism. The 

 fetal energies are, therefore, free to be expended in the process of growth, 

 while gestation profoundly affects the maternal organism. 



Physiological Effects of Pregnancy upon the Mother. — As might have 

 been expected, there is probably not one organic system within the mother's 

 body that is not more or less altered by pregnancy, often morphologically, but 

 especially in i*egard to function. And such normal alterations pass so gradu- 

 ally and so frequently into genuine pathological conditions that it is sometimes 

 difficult to draw the line between the two. The most marked changes are 

 connected with the body of the uterus, and have already been described. The 

 walls of the cervix uteri become hypertrophied, though to a less degree than 

 the body, and their glands secrete a quantity of mucus that forms a plug com- 

 pletely closing the passage-way of the cervix (Fig. 227). The rest of the 

 reproductive organs from the uterus outward become involved in the increased 

 venous hyperemia. The walls of the vagina become infiltrated with serous 

 liquid. The parts of the vulva partake in the general tumefaction. From the 

 second month of gestation onward the mammary glands undergo gradual devel- 

 opment as a preparation for the post-partum lactation. The increase in size of 

 the laden uterus brings gradually increasing pressure to bear upon the abdom- 

 inal viscera, and thus mechanically causes functional derangements of the 

 digestive and the urinary organs. The stretching of the abdominal skin 

 results in localized ruptures of the connective tissue of the cutis, the charac- 

 teristic scars forming the strice gravidarum, which persist after pregnancy. 

 Other organic changes are, however, more profound than these mechanical ones. 

 In accordance with the increased nutritive labor thrown upon the mother, the 

 total quantity of blood in her body is increased, if we can reason from deter 

 minations made upon the lower animals. 1 The condition of the blood has 

 been disputed. The old belief was that the blood of pregnancy is more waterv 

 and contains less haemoglobin than at other times. This is perhaps true for 

 the earlier months, but Schroeder 2 and others have shown that the proportion 

 of haemoglobin and the number of red corpuscles rise above the normal 

 during the later stages. The work of the maternal heart i- increased during 

 gestation. It is maintained by some that the heart beat- more rapidly — 

 according to Kehrer, 3 over eighty times in the minute. It has also been 

 thought, mainly from the results of percussion and from sphygmographic 

 tracings, that the left ventricle is hypertrophied during pregnancy. Post- 

 mortem examination confirms this inference. Pregnancv necessarily throws 



'(). Spiegelberg und R. Gscheidelen: Archivfur Gynakologie, 1872, iv. 

 2 E. Schroeder: Ibid., L890 91, xxxix.; Wild: Ibid., 1897, liii. S. 363. 

 3 F. A. Kelirer: Uebei- die Verdnderungen der Ptdmirve im Paerperium, 1886. 



