oS enero 
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Artificial eee 197 
The natural incubation of chicke r domestic 
fow!s, and of partridges an ph ease [ eet ordinarily 
twenty-one days. Ducks, geese, and turkeys, require thirty- 
six. The artificial process in “Mr. Barlow oven is of the 
same: ‘duration, and it would be injurious to accelerate or 
retard it. As soon as the chicks have broken their shells, 
they are placed i in a cage beneath the even, the temperature 
of which is at cighty degrees Fahrenheit. Here they are left 
three or four days, during which the temperature is gradually 
diminished. They are then exposed to the open air, and in 
aati they are as robust as those that are hatched under 
ens. - 
Mr. Barlow — the progressive ve ia of the 
The second day, the heart Nest to eat on the third, 
appear two vesicles full of blood, the pulsations of which are 
very seusible : the one is the left ventricle. the other the 
base of the . artery. On the fourth, the lien, are dis- 
auricles of the heart. About the sixth the liver is distin- 
guished. The first voluntary movement of the embryo is 
manifest at the end of the 13Ist hour. At the 138th are 
seen the lungs and the stomach, and on the seventh day, 
the intestines, the kidneys, the upper jaw, and two drops of 
blood in place of the one before observed; the brain acquires 
some consistence. On the 8th day the bill opens, and the 
breast is covered with flesh ; on the oth the ribs issue from 
16th the bill opens and shuts, and about the 18th the Heck 
utters the first cry. From this time the animal gradually 
isoreases in strength until it breaks the shell. 
