loo EXAMINATION OF 



* cumdantem membranam teiidit, alter ad lute- 



* um, officio umbilici.' 



Harvey, becaufe Ariftotle fays that the yolk 

 rifes to the fmall end of the egg, coucludes that 

 he had feen nothing himfelf, but that he had re- 

 ceived his information from fome other pretty 

 accurate obferver. In this accufatlon, Harvey 

 evidently injures Arlftotle ; for the.rihng of the 

 yolk to either end, depends folely upon its por- 

 tion during the time of incubation; for the yolk, 

 being lighter than the white, uniformly mounts 

 to the top, whether the large or the fmall end of 

 the egg be uppermoft. This obfervation we owe 

 to William Langley, a phyfician in Dordrecht, 

 who made experiments on the hatching of eggs 

 in the year 1635, about 20 years before Harvey's 

 time *'. 



But, to return to the palTage we have quoted. 

 It is apparent, that the cryftalline liquor, the 

 animated point, the two circles, the two blood- 

 veflels, &c. are defcribed by Ariftotle in the fame 

 manner as they were fcen by Harvey. This 

 anatomiil maintains, that the animated point is 

 the heart, that the heart is the firft part of the 

 foetus which is formed, and that the vifcera and . 

 other members fucceed. All thefe circumftanccs 

 have been mentioned by Ariftotle, and feen by 

 Harvey ; and yet that the heart is firft formed is 

 by no means confonant to truth. To be alfured 

 of this fadt, we have only to repeat the fame ex- 

 periments, 

 * See Langley obferv. editae a Jufto Schradero, Amft. 1674. 



