Gravitation sensitiveness not confined 
to apex of root. 
By 
Frederick Newcombe, 
Ann. Arbor, U. S. A., Univ. of Micbigan. 
With plate III and 6 figures in the text. 
From the time that Charles and Francis Darwini) in 1880 
publi-shed their experiments on the behavior of decapitated roots 
toward gravitation down to the year 1895 when Czapek 2 ) pub- 
lished bis results obtained by the employment of glass caps, the 
contest waged over the qnestion of the perceptive region of the 
root, a contest accompanied by nnmerons polemics and thousands 
of root-decapitations. With the pnblication of Czapek’s work, how- 
ever, the botanical world seems to haye accepted the matter as 
ended, and has apparently given adherence to the view that only 
the apical one or two millimeters of the root-tip acts as the per¬ 
ceptive Organ for gravitation. Earely an anthor, as in the case 
of Eicht er 3) and Jost^), States that the proof is still lacking. 
Now it can be shown that neither'Czapek’s methodnorany 
other method so far employed has or can prove the restriction of 
the perceptive region to the apical two millimeters of the root. 
And this demostration can be given without farther experiment, as 
a matter of logical reasoning. 
Part I: Lack of evidence of localization of geotropic 
sensitiveness. 
As is well known, most roots, when two millimeters of the 
apex are excised, show no farther response to gravitation. This 
resnlt however has not been accepted as demonstrating restriction 
b Power of movement in plants. London. 
2) Untersuchungen über Geotropismus. (Jahrb. wiss. Botanik. XXVII. 
1895. 243.) 
b Zur Frage nach der Funktion der Wurzelspitze. Inauguraldiss. Frei¬ 
burg i. Br. 1902. 
b Beview of papers by Richter, Darwin and Massart. (Bot. Zeit. 
61. 1903. Abt. n. 23.) 
