ANIMALS. l?B 



lengthen ; the belly is closed up, and tumid ; the liver te seen within 

 it very distinctly, not yet grown red, but of a very dusky white ; both 

 the ventricles of the heart are discerned, as if they were two separate 

 hearts, beating distinctly ; the whole body of the animal is covereu 

 over ; and the traces of the incipient feathers are already to be seen. 

 The seventh day, the head appears very large ; the brain is covered 

 entirely over ; the bill begins to appear betwixt the eyes ; and the 

 wings, the thighs, and the legs, have acquired their perfect figure.* 

 Hitherto, however, the animal appears as if it had two bodies ; the 

 yolk is joined to it by the umbilical vessels that come from the belly, 

 and is furnished with its vessels, through which the blood circulates, 

 as through the rest of the body of the chicken, making a bulk greater 

 than that of the animal itself. But towards the end of incubation, the 

 umbilical vessels shorten the yolk, and with it the intestines are thrust 

 up into the body of the chicken, by the action of the muscles of the 

 belly ; and the two bodies are thus formed into one. During this 

 state, all the organs are found to perform their secretions ; the bile 

 is found to be separated, as in grown animals ; but it is fluid, trans 

 parent, and without bitterness : and the chicken then also appears to 

 have lungs. On the tenth, the muscles of the wings appear, and the 

 feathers begin to push out. On the eleventh, the heart, which hither- 

 to had appeared divided, begins to unite ; the arteries which belong 

 to it join into it, like the fingers into the palm of the hand. All these 

 appearances only come more into view, because the fluids the vessels 

 had hitherto secreted were more transparent; but as the colour of the 

 fluids deepen, their operations and circulations are more distinctly 

 seen. As the animal thus, by the eleventh day completely formed, 

 begins to gather strength, it becomes more uneasy in its situation, and 

 exerts its animal powers with increasing force. For some time before 

 it is able to break the shell in which it is imprisoned, it is heard to 

 chirrup, receiving a sufficient quantity of air for this purpose, from 

 that cavity which lies between the membrane and the shell, and which 

 must contain air to resist the external pressure. At length, upon the 

 twentieth day, in some birds sooner, and later in others, the inclosed 

 animal breaks the shell, within which it has been confined, with its 

 beak ; and by repeated efforts, at last procures its enlargement. 



From this little history we perceive, that those parts which are mosi 

 conducive to life, are the first that are begun: the head and the back- 

 bone, which, no doubt, inclose the brain, and the spinal marrow, 

 thougn both are too limpid to be discerned, are the first that are seen 

 to exist ; the beating of the heart is perceived soon after ; the less no- 

 ble parts seem to spring from these : the wings, the thighs, the feet, and 

 lastly the bill. Whatever, therefore, the animal has double, or what- 

 ever it can live without the use of, these are latest in production. Nji 

 ture first sedulously applying to the formation of the nobler organs, 

 without which life would be of short continuance, and would be begun 

 in vain. 



The resemblance between the beginning animal in the egg, and the 

 L-mbry in the womb, is very striking ; and this similitude has induced 



* Haller. 



