1859.] REVIEW. 83 



of the plants in more developed Orders are but modifications 

 or extensions of the simpler elementary organs of vegetation. 



The following quotation merits special consideration^ and it 

 is therefore given in the author's own words. " Quemadmo- 

 dum sui quosque ordines intrant certique organismi nee alii, 

 sic qui cuique organismo intra ordinem locus tribuatur, certa 

 constet lege et ordinandi fas est. Atque naturali methodo per 

 omnes ducta systematis partes, inveniamus quae cuique ordine 

 naturali pertineant ; qua autem lege omnes et singulse partes or- 

 dinis inter se dispoui debeant, et quae sit totius ordinandi norma, 

 hac paragrapho nobis esquirendum est. Quod quo assequamur, 

 lipec disputationes via nobis ingredienda videtur." 



The author next states, what every one is ready to admit, that 

 organisms are composed of a few definite [quibusdam) organs 

 (elements) which in their primordial condition are alike, but in 

 their development are changed, some more, some less. — That 

 from these changes the varieties of both forms and qualities 

 which abound in nature are derived. The generally received 

 name for these changes is Metamorphosis or jMorphology. He 

 next inquires how this metamorphosis is evolved — whether it is 

 exerted or accomplished in a longer or in a shorter space of time. 



When the larva of the insect crawls out of the egg, it gradually 

 comes to perfection, through the nympha stage, till it reaches its 

 imago state. And these changes and the mode of their accom- 

 plishment are proper or peculiar to one and the same individual : 



" HIC METAMOEPHOSIUM ORBEM QUENDAM CONFICIT INDIVIDUUM. 

 . . . PLANTARUM QUOQUE DICITUR METAMORPHOSIS COMMUTATIO 

 ESSE PARTIUM QUJE SENSIM SENSIMQUE PROVENIANT IN UNO EO- 

 DEMQUE INDIVIDUO." 



The author next maintains that there are two kinds of meta- 

 morphosis, viz. first the successive, when the progress is from a 

 simpler or less perfect state to a more complex or perfect con- 

 dition ; and second, the collateral, viz. the changes both in form 

 and function, which organs that are typically identical undergo 

 in different classes, orders, and genera. The author illustrates 

 these laws of morphology or com.parative anatomy from examples 

 taken from the animal kingdom (pp. xxiii. and xxiv.). 



"Duo esse, (inquit auctor,) quibus conditur naturale systema, 

 structur(B norma (organtzationis norma) et perfectione evolutionis 

 forganizatiouis perfectionej ." Hence, if we understand the tcrmi- 



