SECT. II. INTERNAL CHANGES. 



guishable before impregnation ; but when the 

 seed is ripe it is easily detached from the interior 

 parts, though not always easily from the testa. 



With these two integuments the enclosed nucleus 

 of the seed is in its young state almost always fur- 

 nished, and is generally found to consist of the four 

 following parts : the Chorion, the Amnios, the 

 Sacculus colliquamenti, and the Embryo; all, ex- 

 cept the chorion, being the uniform product of fe- 

 cundation, and all, except the embryo, often dis- 

 appearing in the mature state of the seed. 



The Chorion, so named by Malpighi,* is the soft The cho 

 and pulpy substance of the primitive nucleus of 

 the seed, forming at first its principal A mass ; but 

 finally disappearing and leaving no trace of its ex- 

 istence behind, being gradually converted into the 

 nourishment of the other parts. 



The Amnios is a clear and transparent fluid, the The am- 

 product of fecundation, sometimes thin and some- 

 times gelatinous, generated and contained within 

 the chorion, but at last absorbed by the embryo, or 

 converted into a solid substance called the albumen. 



The Sacculus colliquamenti is a thin, white, and The sac- 

 pellucid membrane, originating in the vessels of the 



internal umbilical cord, and being a proper integu- 

 ment with which the amnios is sometimes invested, 



Last of all the Embryo is produced, the principal The em? 

 object of fecundation, and end of all the genital 

 apparatus occupying the centre of the nucleus, but 

 * Opera Omnia, p. 7 1 



