I.N l ROD! I I ION. 



to all known rules. '• When Zo Mr. Milne Edwards, "is only 



itudied in systematic works, it is often supposed that • 



family, and each genua, present to us boundaries pi 



that there can be no uncertainty as to the place to I • 



classification, to everj animal the or/ rhich i- 



known. Bui when we Btudy this science from Nature hei 



convinced of the contrary, and we Bometim the trai 



plan of atructure to an entirely different Bcheme of organisation take j 



i, v ,i, mpletely shaded one ij other that it b 



difficult to trace the line of demarcation between the groups I 



1." Ann. Sc. Nat. 1840, Sept. Raj Ij pointed this out in a 



mv\ remarkable passage, which cannot '• ften quoted. 



•• Verum quod ahaa dixi illud hie repeto et inculco, non sperandam .'i 

 ICethodum undequaque perfectam el omnibu absolutam, quae 



et plantaa in genera ita distribual ut universae species compn hendantur, 

 nulla adhuc anomalA et Bui generis reliqua, et unumquodque aotis 



suis propriis el characteristicis ita circumscrihat, ut nulla.- inveniantur 



is incerti, at ita dicam, laris, et ad plura genera revocabiles. 

 enim id patitur natura rei. Nam. cum Natura (ut dici solet) non 1 

 Baltus, neque ah eztremo a<l extremum transeat nisi per medium, inter 

 sopei inferiores, rerum ordines nonnullas mediae et ambiguse condi- 



tionis producere solet, quae de utroque participent, et utrosque velut con- 



•it. ut ad utrum pertineant omnind incertum .-it. Praet dem 



alma parens in method! cujuscunque angustias 



libertatem et avrovofuap Buam nullis legibus obnoxiam ostentandam, in 

 unoquoque rerum ordine nonnullas species creare solet, tanquam excepti 



rulis generalibus, Bingulares et anomalas. ' — (Rah, // I I nt. vol. i. 

 LdnnsBus < 1 i «1 but copy this when he asserted that Nature maki 

 leaps [Natura ru << facte saltus.—PhiL Bot. i . 



ine has, however, been lately called in question by no 

 eminent a writer than M. AJphonse De Candolle, who requires that absolu te 

 limits should be assigned to all groups of whatever i •• It'.' - he - 



"we cannot Btate in what respect two families differ permanently 



rsally, those two families arc but one. Two pieces of land which 

 touch each other form one island, and not two; but two pieces of land 

 which are separated by an arm of the sea, form two islands, and : 

 — Annates des > 3, vol. 1. p. 254. But this is a kii 



reasoning wholly inapplicable to Natural Bistory, for the reas 

 mirahly given by Ray, and is contrary to all experience. It' the 

 limited by M. AJphonse De Candolle himself arc examined by t) 

 they alone suffice to demonstrate how visionary are Buch ex] Mr. 



Bentham has satisfactorily answered the learned Botanist 

 •• We B itariists," he Bays, " canni I 1"- so mathematically i 

 phers, and where an isthmus • narrow, we must 



with the island. Bow often does it happen that two ' 

 five hundred to two thousand or three thousand stinct 



from rath other in all tl cies by a - 



yet connected by some small isolated genus of a dozen, hall 

 single Bpecies, in which these very characters an 

 tain, or variously combined as to leave no room for thi 

 which we ought to navigate between the two islai /. 



of Botany, 4. 232. It would be very convenient to find tl 

 M. AJphonse De Candolle were practicab le, but in truth th. ■ juite 



Utopian. 



