s 
BOTANY. 55 
work is beautifully, indeed lavishly, illustrated with seventy-eight 
plates, of which thirty-one are colored, nearly every plate repre- 
senting a distinct species highly magnified. The work will com- 
mend itself to microscopists, as it is accompanied by an essay, by 
Mr. Joseph Beck, on the scales of certain Poduræ, with figures of 
the scales highly magnified. 
BOTANY. 
IRRITABILITY OF THE LEAVES OF THE SuNDEw.—In our last 
number attention was called to the old observations of Roth re- 
` specting the irritability of Drosera leaves. It will be interesting 
to our readers to glance at a short abstract of Roth’s treatise.* 
The author begins by referring to the difficulty of drawing any 
line of demarcation between animals and plants. Some plants were 
believed, by the ancient philosophers, to possess a soul, since they 
appear to share with animals a kind of sensitiveness and motion. 
The word sensitiveness is, on some accounts, objectionable and it 
may be better, therefore, to employ the term irritability. A few 
plants possess this irritability in a high degree, but may we not as- 
cribe to others, irritability less in degree? The author next refers 
to the kindred plants Dionea muscipula and Drosera, intimating 
that the latter has, in a slight degree, the kind of irritability which 
characterizes the flytrap. He then describes the action of Dionza 
in catching insects, and proceeds to give an account of the two 
more common species of sundew, Drosera rotundifolia and longi- 
olia. 
In July, 1779, while on a botanical excursion, Roth observed that 
some leaves of both species of Drosera had closed. Upon sepa- 
rating the infolded surfaces, he discovered dead insects, whereupon 
asked himself whether sundew did not act just as Dionæa does. 
He transferred healthy plants to his house and proceeded to make 
the following experiments : — 
lst. He placed, by a pair of pincers, an ant on the open leaf of 
Drosera rotundifolia. As soon as the ant tried to recover its free- 
dom, the hairs of the leaf turned towards his body, and the edges 
of the leaf rolled over towards him. In a few minutes the ant was 
oe eee pare 5 EA eee 
nm yoo 4 
-*Von der Reizbarkeit der Blätter des sog ten S ii 
folia, longifolia.) Beyträge zur Botanik, Erster theil. s.60. Von Albrecht Wilhelm 
Roth. Bremen, 1782. On the Irritability of the Leaves of the so-called Sundew (Dro- 
a rotundifolia). p.60. By Albrecht Wilhelm Roth. 1732 
