Organization in Phcenogamous Plants. 181 



the other case, be presently explained. The first case consti- 

 tutes, however, a singular exception. But I cannot help 

 expressing a doubt as to its being really an exception, and 

 would ask if the said leaf may not perhaps be a foliaceous ex- 

 panded stalk. How long have such grounds been deemed 

 sufficient to overturn a general rule, naturally deducible out 

 of the principle of unity ? It is further a recognised axiom 

 in logic, that an hypothesis is by so much the more allowable, 

 the easier it explains all phaenomena connected with it, and 

 the less it stands in need of other hypotheses for its support. 

 Now I ask, in order to take an extreme case, what abnormal 

 assumptions are not rendered necessary in the explanation of 

 the true placenta centr^alis libera according to the usual mode, 

 as, for instance, in the Plumbaginece (figs. 20 to 23) ? Here the 

 five carpellary leaves would have been bent inwards, have uni- 

 ted by their edges, then have separated themselves once more 

 from their edges, would have again expanded, and then have 

 united to one another anew ; and lastly of at least ten ovula, 

 nine would be abortive, the remaining one having in addition 

 taken a remarkable position upon the summit of the central 

 pillar ; and be it remarked, all this would occur without the 

 possibility of discovering even one step of so complicated a 

 process in the plant itself. It would indeed be universally 

 necessary to have recourse to the supposition of an abortion 

 in all uniovulate ovaries, a circumstance not in the least corro- 

 borated by an appeal to nature. 



The second and opposite case is however almost more dan- 

 gerous still as respects the usual view; for when the entire 

 surface of the carpellary leaf bears ovules, as is the case in 

 the Gentianece^ Nymphccacece^ Butomecc, &c., I know of no 

 tenable explanation of this phaenomenon deducible through 

 the common hypothesis. This has made it necessary to have 

 recourse to many explanations ; sometimes the ovula are re- 

 presented as formed on the edge of the carpellary leaf, some- 

 times on the central nerve*, and sometimes on both. 



* Thus in a work by a M. Eisengrein, entitled " Die Familie de)- Schmet- 

 terlingsbluthigen mit besonderer Hinsicht auf Pflanzen-Physiologie,^'* it is 

 advanced as a law that in the LeguminoscB the ovules are formed on the 

 middle nerve. Independently of the circumstance that the position of the 

 different parts of the flower shows that in this family the convoluted bor- 

 ders of the leaf are the seat of the ovules, M. E. might easily have convinced 

 himself of the uselessness of his lengthy observations, had he taken the 

 trouble to examine a bean-bud with a tolerably strong magnifying glass. I 

 feel indeed disposed to consider the book altogether as a pathological 

 symptom of the spirit of the age. It combines the most barren trifling with 

 empty comparisons, in the style of a modern, but already expiring school, 

 and this is put forth as philosophy ! The book discloses as little investi- 



