148 BOTANICAL GAZETTE [AUGUST 
still holds to his former view concerning the motor mechanisms of Mimosa, in 
spite of the doubt cast upon his theory by the work of MacDovucat and Frrrine. 
The noteworthy changes that are to be found in this third edition make it 
necessary for all libraries. Many among us may not accept the teleological views 
that are to be found throughout the work, and it may occasion disappointment 
to find at several points, as stated above, that the author maintains his own 
unstable theories in the face of what will appeal to most botanists as conclusive 
proof against them. In particular, it is highly doubtful if we may longer believe 
in the condensing power of the aerial roots of orchids, conduction by the shortest 
route as explaining the elongation of palisade cells, the conductive function of 
latex tubes, the secretive rather than storage function of aleurone, or the hydro- 
static propagation of stimuli in Mimosa. 
The teleological views of the author are apparently not merely conveniences 
of expression, but purpose in plant structures appears to be regarded as an objec- 
tive reality, which operates as a cause in the development of plant organs and 
tissues. As a consequence, it may not be surprising that the author is almost 
violent in his opposition to the contributions of such men as DEVAUX, SPANJER, 
and WIELER, and gives no place at all or at most inadequate consideration to 
the work of such men as GRIFFON, BERNARD, and FRIEDEL. The trend of 
modern investigation is certainly away from the idea that purpose is the directive 
factor in the evolution of structures, as well as from the idea that all structures 
must have a definite and advantageous function. However, the vast majority 
of structures are certainly useful, and the study of function in relation to structure 
gives life and vitality to what is otherwise a dead and profitless study to most 
students. And for this reason HABERLANDT’s work fills a place that is taken by 
no other work. For this reason, too, it is much to be hoped that there will soon 
be available a translation of this third edition.—H. C. Cow Les. 
Smoke and vegetation. 
THERE have been a number of treatises dealing with the injurious effects 
of smoke on vegetation, but we are now favored with a monographic treatment 
of the subject by Hasetuorr and Linpav.3 There are first some general Bi 
siderations on the origin of smoke, the characteristics and extent of its injune 
to plants, the various causes of the formation of leaf spot, and the on 
of normal plant characteristics with in juries due to smoke. The body of the wor 
deals with the injurious smokes and vapors in detail. Particular atten pe 
paid to the effect of sulfurous and sulfuric acid vapors. Injurious € ace 
found to be associated chiefly with the foliage organs; little or no eS 
to the plant through vapors which may have been absorbed by the soil. 4 ia 
ful effects are made evident through the formation of leaf spots, the wes : 
leaves and young branches, the disorganization of chloroplasts, P — 
3 HasELHorr, E., and Linpav, G., Die Beschadigung der Vegetation ap 
Rauch: Handbuch zur Erkennung und Beurteilung von Rauchschaden. Imp: 
PP. vilit+412. figs. 27. Berlin: Gebriider Borntraeger. 1903. M10- 
tion is 
