CHAP. II. OVULE. 177 



ging into a seed. Its internal structure is exceedingly difficult 

 to determine, either in consequence of its minuteness, or of 

 the extreme delicacy of its parts, which are easily torn and 

 crushed by the dissecting knife. It is doubtless owing to this 

 circumstance chiefly, that the anatomy of the ovule was almost 

 unknown to botanists of the last century, and that it has only 

 begun to be vmderstood within ten or twelve years, during 

 which it has received ample illustration from sevei'al skilful 

 observers. Brown, indeed, claims to have pointed out its real 

 nature so long ago as 1814; but the brief and incomplete 

 terms then used by that gentleman, in the midst of a long 

 description of a single species, in the Appendix to Captain 

 Flindes's Voyage, unaccompanied as they were by any ex- 

 planatory remarks, prove indeed that he knew something 

 of the subject, but by no means entitle him to the credit of 

 having, at that time, made the world acquainted with it. The 

 late Mr. Thomas Smith seems to deserve the honour of having 

 first made any general remarks upon the subject: of what 

 extent they exactly were is not kno^v^l, as his discoveries, in 

 1818, were communicated, as it would seem, in conversation 

 only; but it is to be collected from Brown's statement that 

 they were of a highly important nature. Since that period 

 the structure of the ovule has received much attention from 

 Brown, in England; Turpin and Adolphe Brongniart, in 

 France ; and Treviranus, in Germany ; by all of whom the 

 subject has been greatly illustrated. It is, however, to Mir- 

 bel, — who, by collecting the discoveries of others, examining 

 their accuracy, and combining them with numerous admirable 

 observations of his own, has given a full account of the gra- 

 dual development and the different modifications of the ovule, 

 — that we are indebted for by far the best description of that 

 important organ. His two papers read before the Academy 

 of Sciences at Paris, in 1828 and 1829, are a perfect model 

 of candour and patient investigation, and form the basis of 

 what is here about to be recorded on the subject. I regret, 

 however, that the space which can now be devoted to the 

 explanation of the structure of the ovule is by no means such as 

 its intricacy and interest demand. 



As the ovules are the production of the placentae, they 



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