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CHAPTER VL 



STRUCTURE OF EGGS. 



BEFORE entering upon the details of hatching, it 

 seems indispensable to give some account of the 

 structure of eggs ; and in order to render this curious 

 but difficult subject as plain as possible to those but 

 little acquainted with physiology, we shall trace the 

 egg from its appearance in the ovarium, or " egg- 

 organ" (as we may call it), of the hen, till the final 

 exclusion of the chick in the process of hatching. 

 This subject has been investigated with much care 

 and skill by some of the most distinguished observers 

 and experimentalists, in consequence of the light it 

 was expected to throw upon obscure points in the 

 early history of other animals, whose development 

 was of more difficult if not of impossible observation. 

 Amongst the illustrious men who have engaged in 

 these researches we may name Harvey, Malpighi, 

 and Haller ; and, in our own times, Spallanzani, Blu- 

 menbach, Scarpa, Prander, Meckel, Dutrochet, Sir 

 E. Home, and Dr. Paris. The chief facts which they 

 have ascertained we shall now endeavour to con- 

 dense into a brief but explicit sketch. 



The egg of a bird appears in the egg-organ (ova- 

 rium) under the form of a small yellow globe or 

 sphere, frequently smaller than mustard-seed, but 

 gradually increasing in size till it drops from its slen- 

 der fastening and falls into the egg-tube (pviductus) . 

 The egg-organ contains all the eggs which are to be 



