364 QUARTERLY JOURNAL. 



2d Day. The eyes begin to make their appearance about the 

 thirtieth hour ; and additional vessels, closely joined together, indi- 

 cate the situation of the navel : the brain and spinal marrow, rudi- 

 ments of the wings, and principal muscles, become observable ; the 

 formation of the head is also evidently proceeding. 



3d Day. The heating of the heart is perceptible, although no blood 

 is visible : after a few hours, however, two vesicles, containing 

 blood, make their appearance ; one forming the left ventricle, the 

 other the great artery : the auricle of the heart is next seen, and, in 

 the whole, pulsation is evident, 



4ih Day. The wings now assume a more defined shape ; and the 

 increased size of the head render.s the globules containing the brain, 

 the beak, and the front and hind part of the head, distinctly visible. 



5th Day. The liver makes its appearance ; and both auricles, now 

 plainly seen, approach nearer the heart than before : that splendid 

 phenomenon, the circulation of the blood, is now evident. 



6th Day. The lungs and stomach are distinguishable, and the full 

 gush of blood from the heart is distinctly apparent. 



7ih Day. The intestines, veins, and upper mandible become 

 visible, and the brain begins to assume a distinct form. 



8lh Day. The beak for the first time opens, and the formation of 

 flesh upon the breast commences. 



9th Day. The deposition of matter forming the ribs takes place, 

 and the gall-bladder is perceptible. 



10th Day. The bile is distinguishable by its green color ; and the 

 first voluntary motion of the body of the chick is seen, if separated 

 from its integuments. 



llth Day. The matter forming the skull now becomes cartilagi- 

 nous, and the protrusion of feathers may be noticed. 



12th Day. The orbits of sight are apparent, and the ribs arc 

 perfected. 



13th Day. The spleen gradually approaches to its proper position 

 near the stomach. 



1 4th Day. The lungs become enclosed within the breast. 



15th, 16th and 17th Days. During these days, the infinity of 

 phenomena in this wonderful piece of vital mechanism elaborate it 

 into more perfect form, and it presents an appearance closely 

 approaching the mature state ; the yolk of the egg, however, from 

 which it derives its nourishment, is still outside the body. 



18th Day. On the eighteenth day, the outward and audible sign 

 of developed life is apparent, by the faint piping of the chick being, 

 for the first time, heard. 



19th, 20th and 21st Days. Continually increasing in size and 

 strength, the remainder of the yolk gradually becomes enclosed 

 within its body ; then, with uncommon power for so small and frail 

 a being, it liberates itself from its prisun in a peculiar and curious 

 manner, by repeated efforts made with its bill, seconded by muscular 

 exertion with its limbs, and emerges into a new existence. 



