236 ON GENERATION. 



imbibed a larger quantity of blood, it becomes enlarged, and 

 starts into view; in the systole, however, subsiding instan- 

 taneously as if convulsed by the stroke, and expelling the blood, 

 it vanishes from view. 



Fabricius depicts this palpitating point in his third figure; 

 and mistakes it a thing which is extraordinary for the body 

 of the embryo ; as if he had never seen it leaping or pulsating, 

 or had not understood, or had entirely forgotten the passage in 

 Aristotle. A still greater subject of amazement, however, is 

 his total want of solicitude about his chalazse all this while, 

 although he had declared the rudiments of the embryo to be 

 derived from them. 



Ulyssus Aldrovandus, 1 writing from Bologna nearly at the 

 same time, says : " There appears in the albumen, as it were, a 

 minute palpitating point, which The Philosopher declares to be 

 the heart. And I have unquestionably seen a venous trunk arising 

 from this, from which two other branches proceeded; these are 

 the blood-vessels, which he says extend to either investing mem- 

 brane of the yelk and white. And I am myself entirely of his 

 opinion, and believe these to be veins, and pulsatile, and to 

 contain a purer kind of blood, adapted to the production of the 

 principal parts of the body, the liver, to wit, the lungs, and 

 others of the same description." Both of the vessels in ques- 

 tion, however, are not veins, neither do they both pulsate ; but 

 one of them is an artery, another a vein, as we shall see by and 

 by, when we shall farther show that these passages constitute 

 the umbilical vessels of the embryo. 



Volcher Goiter has these words : " The sanguineous point or 

 globule, which was formerly found in the yelk, is now observed 

 more in the albumen, and pulsates distinctly." He says, erro- 

 neously, " formerly found in the yelk ;" for the point discovered 

 in the vitellus is white, and does not pulsate; nor does the san- 

 guineous point or globe appear to pulsate at the end of the 

 second day of incubation. But the point which we have indi- 

 cated in the middle of the circle, and as constituting its centre 

 in connexion with the vitellus, disappears before that point which 

 is characterized by Aristotle as palpitating, can be discerned; 

 or, as I conceive, having turned red, begins to pulsate. For 



1 Ornithologia, lib. xiv, p. 217. 



