732 CHEMISTR Y OF RESPIRA TION. 



prevent vigorous contractions of the uterus, the blood in the umbilical 

 vein of the foetus was brighter than that in the arteries ; and that the 

 difference in colour of the umbilical vein and arteries disappeared 

 during asphyxia of the mother, to reappear when artificial respiration 

 was performed. Pfliiger 1 had also noticed that the colour of the 

 umbilical vein was reddish brown in the normal condition, but became 

 black during asphyxia. 



The results obtained by Zweifel were confirmed and extended by 

 Zuntz, 2 who showed that during asphyxia of the mother the foetal blood 

 lost oxygen in the placenta, the blood of the umbilical vein becoming 

 darker than that of the corresponding arteries ; that when the maternal 

 vessels supplying the placenta were compressed the umbilical vein 

 became as dark as the arteries ; that a foetus respiring air through its 

 lungs lost oxygen in the placenta, which was left connected with an ex- 

 cised piece of the uterus ; that during normal breathing of the mother 

 the umbilical vein coming from the intact placenta contained blood as 

 red as the arterial blood of the 'uterus, and that movements of the 

 foetus made the blood of the umbilical arteries darker in colour. Zuntz 

 maintains that the oxidation taking place in the foetus must be small, 

 for the difference in the colours of the umbilical arteries and vein is 

 slight, corresponding to a difference of about 1 per cent, in the amount 

 of oxygen ; and the foetus can live for a long time upon the oxygen in 

 its blood, when respiration by the placenta or lungs is prevented. 

 According to Zuntz's estimate, the human foetus would need daily 

 0*169 grin, of oxygen per kilo, of its weight, as compared with 

 14-15 grms., the amount required by an adult. 3 Pn tiger 4 and 

 Zuntz found that the blood of the foetus, in comparison with that 

 of an adult, had a low specific gravity and was poor in corpuscles 

 and haemoglobin ; these results, however, are opposed to those 

 of Hayem, 5 Hoesslin, 6 Sorensen, 7 Wiskemann, 8 Preyer, 9 Denis, 10 and 

 others, 11 who found higher values for the foetus than for the 

 mother. 



The difference in the tension of oxygen in the blood of the 

 umbilical artery of the foetus and the maternal blood is small, 

 but it is sufficient, owing to the intimate relationship of the 

 maternal and foetal circulations, to supply the oxygen needed by the 

 foetus. 12 



Cohnstein. and Zuntz 13 have analysed the blood of the umbilical 

 artery of a foetal sheep, which was 53 cm. long, weighed 1535 grms., 



1 Arch.f. d. ges. PhysioL, Bonn, 1868, Bd. i. S. 80. 



-Ibid., Bonn, 1877, Bd. xiv. S. 605. 



"This is contested by Wiener, Arch.f. Gynaek., Berlin, 1884, Bd. xxiii. S. 183. This 

 paper gives numerous references to the work on the general metabolism of the foetus, but 

 does not disprove the relatively small oxidation in the foetus. 



4 Arch.f. d. ges. PhysioL, Bonn, 1868, Bd. i. S. 61 ; 1875, Bd. x. S. 274. 



5 Compt. rend. Acad. d. sc., Paris, 1877, tome Ixxxiv. p. 1166. 



6 Ztschr.f. BioL, Munchen, 1882, Bd. xviii. S. 612. 



7 Jahresb. u. d. Fortschr. d. Anat. u. PhysioL, Leipzig, 1878, Bd. v. Abth. 3, S. 192. 



8 Ztschr.f. BioL, Miinchen, 1876, Bd. xii. S. 434. 



9 " Specielle Physiol. des Embryo," Leipzig, 1883, S. 144. 



10 Ann. de chim. etphys., Paris, 1842, Ser. 3, tome v. p. 313. 



11 Poggiale, Compt. rend. Acad. d. sc., Paris, 1847, tome xxv. p. 112 ; Panum, 

 Firchoiv's Archil", Bd. xxix. S. 481. See also Cohnstein and Zuntz, Arch.f. d. ges. PhysioL, 

 Bonn, 1884, Bd. xxxiv. S. 183. 



12 Zuntz, ibid., 1877. Bd. xiv. S. 626. 



13 Arch.f. d. ges. PhysioL, Bonn, 1884, Bd. xxxiv. S. 206, 231. 



