SECT. 2] TO THE RENAISSANCE loi 



time afterwards, however, they settle down a little and lose their swelling 

 owing to the digestive action of the heat — and all this is brought about by 

 the action of the formative virtue carried along the passage which is 

 directed to the head, but before arriving there is separated and ramified 

 by the great vein of the albumen-membrane, as may be clearly seen by 

 anyone who breaks an egg at this time and notes the head appearing in 

 the wet part of the egg and at the top of the other members. For what 

 appears first in the making of a foetus are the upper parts because they are 

 nobler and more spiritual being compacted of the subtler part of the egg 

 wherein the formative virtue is stronger. When this happened one of the 

 aforementioned two passages which spring from the heart branches into 

 two, one of them going to the spiritual part which contains the heart and 

 divides there in it carrying to it the pulse and subtle blood from which the 

 lungs and other spiritual parts are formed, and the other going through 

 the diaphragm \dyqfracmd\ to enclose within it at the other end the yolk 

 of the Qgg, around which it forms the liver and stomach. It is accordingly 

 said to take the place of the umbilicus in other animals and through it food 

 is drawn in to supply the flesh for the chick's body, for the principle of genera- 

 tion of the radical members of the chick comes from the albumen but the food 

 from which is made the flesh filling up all the hollows is from the yolk." 



After ten days, Albert goes on to say, all the constituent organs 

 are mapped out and the head is greater then than the rest of the 

 body put together. He observes that the yolk liquefies early in 

 development and that slimy concretions are present in the allantoic 

 fluid later on (uric acid). But the passage quoted does demonstrate 

 that before further progress could be made some better name must 

 be found than "the interior membrane to which the first vessel 

 proceeds" for a given structure. 



Albert, however, was accomplishing a good work. One of his best 

 amplifications of Aristotle was his description of the relationship 

 between yolk and embryo in fishes. Just as his words about the chick 

 demonstrate that he must have opened hen's eggs at different stages 

 during incubation, so his words about fish eggs show that he must 

 have dissected and examined them also. Thus (Book vi, tractate 2, 

 chap, i) he says, "Between the mode of development [anathomiam 

 generationis] of birds' and fishes eggs there is this diflference ; during 

 the development of the fish the second of the two veins which extend 

 from the heart does not exist. For we do not find the vein which 

 extends to the outer covering of the eggs of birds which some wrongly 

 call the umbilicus because it carries the blood to the outside parts, 

 but we do find the vein which corresponds to the yolk vein of birds, 

 for this vein imbibes the nourishment by which the limbs increase. 



