Ornithology. 177 



eigg. This, which some call the punctum saliens, or punctum 

 vitce, was found in those that were impregnated by the male to be 

 large but in the others small. Upon examination with the micro- 

 scope it was found to be a kind of bag, containing a transparent 

 Hquor in the midst of which the embryo was seen. The embryo 

 resembled a composition of little threads, which the warmth of 

 future incubations tended to enlarge. 



Upon placing the egg in a proper warmth, after six hours the 

 vital speck begins to dilate Kke the pupil of the eye. The head 

 of the chicken is distinctly seen, with the back-bone something 

 resembhng a tadpole floating in its ambient fluid, but as yet seem- 

 ing to assume none of the functions of animal life. About six 

 hours more the httle animal is seen more distinctly; the head be- 

 comes more plainly visible, and the vertebras of the back more 

 easily perceivable. All these signs of preparation for life are in- 

 creased in SIX hours more; and, at the end of twenty-four, the 

 ribs begin to take their places, the neck begins to lengthen, and 

 the head to turn to one side. 



At this time, the fluids in the egg, seem to have changed places ; 

 the yolk which was before in the centre of the shell, approaches 

 nearer the broad end. The watery part of the white is diminish- 

 ed, the grosser part sinks to the small end; and the little animal 

 appears to turn towards the part of the broad end in which a cav- 

 ity has been described, and with its yolk seems to adhere to the 

 membrane there. 



At the end of forty hours the great work of life seems fairly 

 begun, and the animal plainly appears to move; the back bone 

 thickens; the first rudiments of the eyes begins to appear; the 

 heart beats, and the blood begins already to circulate. The 

 parts, however, as yet are fluid, but by degrees, become more 

 and more tenacious. At the end of two days, the liquor in which 

 the chicken swims, seems to increase; the head appears with two 

 little bladders in place of eyes; the heart beats in the manner of 

 every embryo where the blood does not circulate through the lungs. 

 In about fourteen hours after this, the chicken is grown more 

 strong; the veins and arteries begin to branch, in order to form 

 the brains; and the spinal marrow is seen stretching along the 

 back bone. In three days, the whole body of the chicken ap- 

 pears bent; the head with its two eye-balls, with their different 

 humours, now distinctly appear; and five other vesicles are seen, 

 which soon unite to form the rudiments of the brain. The out- 

 lines also of the thighs, and wings, begin to be seen, and the body 

 begins to gather flesh. At the end of the fourth day, the vesicles 

 that go to form the brain approach each other; the wings and 

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