( 1H7 ) 



luis later been proved lo Ix' false. AjkI in spile of all (lie praise 

 Avhieli Sachs jnsily beslows (Mi him, he adds ihat Ditkociikt "sieh 

 <»f( dnreli seine ei<^enen Vorni'lheile beirren lies//' '). 



Meanwhile the qnestion remained nnsellled, for Dutkociikt gave 

 oidy a negation and no explanation. On Dee. 9, 1829, he also read 

 his artiele to the vSoeiété de Pharmaeie de Paris -'). 



In i8o2 api^eared the Physiologic végétale by A. P. uk Candou.k 

 who gave a short description of the experiments of Pinot and Mui.ükk •'). 

 He wrongly was of opiJiion that Pinot fixed the seeds, for his silver 

 needle was a movable balance. From jMui.dkr's experiments he drew 

 the conclusion that the roots penetrated into the mercury on acconnt 

 of their "stiffness"; the tender roots of the buckwheat were not stiff 

 enough then to force themselves in. To the penetration of freely 

 floating seeds he opposed Dutkochet's negation. 



Several handbooks of those days, as those of Bischoff, Lindlky, 

 Trfa'IRAnus and Meyen, make no mention of the experiments with 

 mercury. Dutrochet himself omits them entirely from his "JMémoircs 

 pour servir a I'histoire anatomique et physiologique des végétaux et 

 des animaux", 1837. 



On Ma}' 27,1844, however, Payer sent a paper to the Académie, 

 entitled "Memoire sur la tendence des racines a s'enfoncer dans la 

 terre et sur leur force de penetration." In this paper lie described 

 his experiments which seemed to confirm Pinot's ol)ser\^ations. The 

 paper itself does not seem to have been printed ; an extract of it 

 however was given by Payer in the Comptes Rendus ■*), while an 

 elaborate report of it occurs in tlie Comptes Rendus of 1845 ^). 



Payer devised an apparatus in order to determine the deiith to 

 Avhicli a germroot could penetrate into the mercuiy. For this [lurpose 

 he used layers of mercury of varying thickness, being at the bottom 

 in contact with a layer of water. In a glass trough namely, one or 



1) Sachs, Gescliichte der Botaiiik 1875 p. 555. 



2) Journal de Phamacie Tome XVI 1830 p. 28. 



^) X. P. DE Candolle, Physiologie végétale Tome II 1832 p. 827—828. 



^) Comptes rendus Tome XVIII. 1844 j^ag. 993—995. Hofmeister gives p. 933 

 instead of p. 993; this mistake is found in the following papers: 



HoFMEisTER, Bel', der köu. Sachs. Ges. d. Wiss. zu Leipzig XII 18G0 p. 203. 



Hofmeister, Piingsli. Jahrb. Ill 18G3 p. 105. 



HoFMEisTER, Die Lelne von der Pdanzenzelle 18ü7 p. 284. 



A. B. Frank, Beitriige zur Pflanzenpliysiologie, 1868 p. 22. 



Th. GiEsiELKi, in Cohn's Beilriigc zur Biologie der Pflanzen I, 2 1872 p. 11. 



A. ScHOBER, Die Anschauungcn iiber den Geotropismus der Pdanzen seil Knight, 

 1899 pag. 9. 



'') Comptes rendus Tome XX bsi5 p. 1257- 12()8. 



13 



Proceedings Royal Acad. Amsterdam, Vol. VI. 



