CHANGES DURING PREGNANCY 549 



According to Veit and Seholten,i the villi can dissolve intact red 

 cells of the circulating blood, just as the solution of erythrocytes can 

 be produced by placental extracts. As a result of this, hiemo- 

 globinaemia may occur in pregnancy. Wychgel ^ observed it in eight, 

 out of twenty-three pregnancies, and the condition occurs more- 

 frequently still in eclampsia. At present, however, it is not yet 

 generally accepted that an erythrotoxin is formed by the syncytium, 

 though Bonnet^ has shown histologically that a destruction of red 

 cells probably takes place during life. He noticed on the surface of 

 the villi " perfect and damaged erythrocytes in all stages of degenera- 

 tion, clumping and solution." So Hofbauer found, by adding neutral- 

 red to the chorionic villi of two fresh two-months' placentae teased iu 

 saline, that many of the blood corpuscles showed red dots indicating 

 degeneration. 



(&.) Calcium. — The great demand for calcium by the developing 

 embryo, especially during the last three months of pregnancy, would 

 lead one to suppose that pregnancy involves a loss of calcium on the 

 part of the mother. It has, in fact, been stated that teeth are apt to 

 become brittle in pregnancy from a decrease in calcium fluoride 

 ■ and a deficiency in enamel formation.* Evidence of a special 

 drain on calcium is also found in puerperal osteomalacia, which 

 occurs in poor people who presumably live on an ill-constructed 

 diet, and which has been produced experimentally as the result 

 of such a diet in animals.^ The effect on the teeth is not admitted 

 as a general occurrence in pregnancy by some authorities,^ if it 

 occurs at all, and is probably the result of a diet deficient in calcium. 

 The exact observations of Hoffstrom have shown clearly that on a 

 suitable calcium-rich diet the mother actually gains in calcium. On 

 such a diet Hoffstrom's patient retained 34"3 gja. Ca during the whole 

 pregnancy, of which 30'1 gm. were required by the foetus, so that the 

 mother ended her pregnancy with a net gain of 4-2 gm. Ca. As has 

 been stated, the requirements of the fostus are particularly high 

 during the last three months of pregnancy, and the mother responds 

 to this increased call for calcium by diminishing the excretion of 

 calcium in the urine and to a lesser extent by the intestine. Even 

 on this diet and with a total positive balance there are short periods of 



^ Veit and Scholten, " Synzytiolyse und Hamolyse,'' Zeitsch. f. Oehurtsh. u. 

 0//iidi:, vol. xlix. 



2 'VVychgel, " Untersucliungen iiber das Pigment der Haut und der Urin 

 wahrend der Sehwangerscliaft," Zeitseh. f. Oeburtsh. u. Gyntik., vol. xlvii. 



^ Bonnet, quoted by Hofbauer {Biologie der Tnefiisohliclien Plazmita, Wien und 

 Leipzig, 1905). 



* Terrier, " De Finfluenee de la grossesse sur les dents," These de Paris, 1899. 



5 Stilling and Mering, "Ueber experimen telle Erzeugung von Osteomalacia," 

 Zentralbl.f. med. Wissensohaft, 1889. 



" Dr. Sim Wallace, Private communication. 



