Part I. in /^^ C r e at i o n. 73 



(Indeed this lower Region of it, by Reafon of 

 the Weight of the Superincumbent, is always 

 in a compreffed State) hath, been made Ufe of 

 in the common Weather-Glafles, in Wind-Guns, 

 and in feveral ingenious Water- Works, and 

 doubtlefs hath a great Intereft in many natural 

 EfFedts and Operations. 



Againft what we have faid of the Neceffity of 

 tha Air for the Maintenance of the Vital Flame, 

 it may be objeded, That the Foetus in the 

 Womb lives, its Heart pulfes, and its Blood 

 circulates \ and yet it draws in no Air, neither 

 hath the Air any Accefs to it. To which I an- 

 fwer. That it doth receive Air, fo much as is 

 fufRcient for it in its prefent State, from the 

 maternal Blood by the Placenta Uterina^ or the 

 Cotyledons, This Opinion generally propounded, 

 viz. That the Refpiration of the Dam did 

 ferve the Fcetus alfo, or fupply fufficient Air to 

 it, I have met with in Books ; but the explicit 

 Notion of it I owe to my Learned and Worthy 

 Friend Dr. Edward Hulfe, which, comparing 

 with -mine own Anatomical Obfervations, I 

 found fo confonant to Reafon, and highly pro- 

 bable, that I could not but yield a firm Aflent 

 to it. I fay then, That the chief Ufe of the 

 Circulation of the Blood through the Cotyledons 

 of a Calf in the Womb, (which I have often 

 diffefted) and by Analogy thro' the Placenta Ute^ 

 r/;^^ in an ^u man Fcetus, feems to be the Im- 

 pregnation of the Blood with Air, for the Y^^A- 

 ing of the Fital Flame : For if it were only for 

 Nutrition, what Need of two fuch great Arte- 

 ries 



