CHANGES IN THE MATERNAL ORGANISM 521 



the lymphoid tissue of the endometrium, and by others to an 

 increase in the groups of lymphatic glands in the neighbourhood 

 of the genital apparatus. 



According to Spiegelberg and Gscheidlen, the total amount 

 of blood is increased during pregnancy in the dog from 7 '8 per 

 cent, to 9 per cent, of the body-weight. There is no essential 

 difference in the specific gravity (Nasse, Blumreich ^). The 

 observations on the alkaUnity of the blood are few and con- 

 tradictory. Lebedeff states that it is increased, and similarly 

 Blumreich, who investigated the blood of pregnant rabbits 

 and women. The alkahnity quickly returned to the normal 

 level. On the other hand, Payer's estimations of the 

 " diffusible " alkali, i.e. alkali not combined with protein, 

 of defibrinated blood give values sUghtly below the non- 

 pregnant level. The molecular concentration of the blood 

 shows no change during pregnancy. 



h. The Heart and Circulation. — Older authorities stated that 

 a true hypertrophy of the heart occurred during pregnancy, 

 and was caused by the increased length and size of the uterine 

 vessels, the placental circulation, and the compression of the 

 aorta by the gravid uterus. Experiments showed, however, 

 that the uterine vessels did not offer a resistance which required 

 an increase in the work of the heart (Engstrom ^), while the 

 compression of the abdominal aorta and the introduction of 

 large quantities of fluid into the abdominal cavity produced no 

 change which could be detected from the pulse (Heinricius ^). 

 The controversy has been a long one, but it does not properly 

 belong to this article. The present-day opinion of the cardiac 

 modifications in the human female may be summed up as 

 follows : Tendency to dilatation, especially of the right heart, 

 and to some compensatory hypertrophy. The frequent em- 

 barrassment of the right ventricle, even in the early stages of 

 pregnancy, is marked by the occurrence of shortness of breath 



' Blumreich, "Der Einfluss der Graviditat auf die Blutalkalesoenz," 

 Arch. f. Oyndk., vol. lix. , 1899. 



' Engstrom, "L'Influence de la grossesse sur la circulation," Arch, de 

 Gyn., 1886, vol. ii. 



' Heinricius, ExperimenteUe und klinische Untersuchungen iiber Circula- 

 tionsverhalten der Mutter und der Frucht, Helsingfors, 1889. 



