198 The Botanical Gazette. (May, 
Strassburg), and especially of FRANK SCHWARZ (at the For- 
estry Academy at Eberswalde). 
he tendency to give a mathematical aspect to observed 
phenomena controlled Nigeli’s investigations of apical growth, 
which he published in 1845. Ina similar way, but with in- 
dependent broadening and deepening of the problem, W. HOF- 
MEISTER (Heidelberg, Tiibingen, died in 1877), followed the 
course of development of the organs of the plant from the proc- 
esses of division which take place in growing points and embryo 
and in 1851 published his now famous comparative researches 
on the germination, development, and fruiting of the higher 
cryptogams, and the formation of seeds in the Conifere. 
Those researches laid the foundations for a phylogeny of the 
vegetable kingdom ten years before the appearance of Charles 
Darwin’s ‘Origin of Species.” The value of a knowledge of 
development, of morphological comparisons based on exhaust- 
ive investigation, was thus set in a new light, and a broad 
field was opened for further study. That many single state- 
ments in this book were erroneous does not in any way dimin- 
ish its value, for this rests on the broad foundation of the 
whole wor 
Hofmeister’s remarkable ability to comprehend the homolo- 
gies of the most remote divisions of the vegetable kingdom, 
gave permanent value to his morphological comparisons. At 
the same time, the gulf which seemed to separate the crypto- 
gams from the phanerogams was bridged by Hofmeister’s dis- 
coveries, and the processes which take place in the formation 
of the embryo among phanerogams, were set in their proper 
relations with the alternation of generations among the higher 
cryptogams. In the field thus opened by Hofmeister, Prings- 
heim labored with similar objects in view, but with limita- 
tions of the problem, and his achievements are now classical 
in every detail. Gaps in our knowledge have been closed by 
the valuable contributions of METTENIUS(Leipzig, died in 1866), 
CRAMER (of Ziirick), von Hanstein, Kny, and Strasburget. 
LEITGEB (of Graz, died in 1888) devoted to the Hepatice 
seven full years of the most careful study along similar lines. 
The value of these researches, which laid bare the origin, 
development and homologies of the organs of the plant, will 
be permanent, despite the fact that the early investiga- 
tions, inaugurated by Niigeli, of the processes of division 
