#3 OXYGENATIOtt OF BLOOD. SECT. XXXVIIX. $. 



minutes after their birth ; while puppies and kittens 

 remain many days without opening their eyes. And 

 though on the reparation of the cotyledons of ru- 

 minating animals no blood is effufed, yet this is 

 owing clearly to the greater power of con trad ion 

 of their uterine lacunas or alveoli. See Medical 

 Mays, Vol. V, page 144. And from the fame caufe 

 they are not liable to a fangurfer^us menftruation. 



The neceffity of the oxygenation of the blood in 

 the fetus is farther illuflrated by the analogy of the 

 chick in the egg ; which appears to have its blood 

 oxygenated at the extremities of the veffels fur- 

 rounding the yolk j which are fpread on the air-bag 

 at the broad end of the egg, and may abforb oxy- 

 gene through that moift membrane from the air 

 confined behind it ; and which is fhewn by experi- 

 ments in- the exhaufled receiver to be changeable 

 though the (hell. 



This analogy may eve^n be extended to the grow- 

 ing feeds of vegetables ; which were fhewn by Mr. 

 Scheele tor require a renovation of the air over the 

 water, in w'hicb they were confined. Many vege- 

 table feeds are furrounded with air in their pods or 

 receptacles, as peas, the fruit of ftaphylea, and lich- 

 nis veficaria 1 ; but it is probable* that thofe feeds, 

 after they are fried, as well as the fpawn of fifh, by 

 the fituation of the former on or near the moid and 

 aerated furface of the earth, and of the latter in the 

 ever-changing and ventilated water, may not be in 

 need of an apparatus for the oxygenation of their 

 firft blood, before the leaves of one, and the gill* 

 of the other, are produced for this purpofe* 



III. j. There .are many arguments, befides tfie 

 ltri& analogy between the liquor amnii and the 

 albumen ovi, which mew the former to be a nutri- 

 tive fluid ; and that the fetus in the latter months 

 ef pregnancy takes it into its ftomach j and that 



in 



