372 OXYGENATION, &c. SECT. XXXVIII, 3. 3. 



the placenta is an organ for the purpofe of giving due oxygena- 

 tion to the blood of the fetus ; which is more neceflary, or at 

 leaft more frequently neceflary, than even the fupply of food. 

 The queftion of the great Harvey becomes thus eafily anfwer- 

 cd. " Why is not the fetus in the womb fuffocated for want 

 of air, when it remains there even to the tenth month without 

 refpiration : yet if it be born in the feventh or eighth month, 

 and has once refpired, it becomes immediately fuffocated for 

 want of air, if its refpiration be obftrufted ?" 



For further information on this iubjeft, the reader is referred 

 to the Tentamen Medicum of Dr. Jeffray, printed at Edinburgh 

 in 1786. And it is hoped that Dr. Forefter will fome time 

 give his thefes on this fubjeft to the public. 



SECT, 



