PERIODICAL PHZANOMENA OF ANIMALS AND VEGETABLES. 327 
go out without corn in the ear ; it is curious to determine at what period these 
cerealia put forth the ear in the various parts of Belgium and Europe. 
According to the request of a large number of observers, we have classed 
the plants recommended to their attention in alphabetical order. The list 
has been increased by the addition of some new plants; but on the other 
hand, the Academy has resolved not to include in its publication any plants 
but those selected for the observers. To admit all observations indiscrimi- 
nately would be to encumber the Memoirs of the Academy, and to render 
comparisons almost impossible; whilst, by the arrangement we have adopted, 
an analysis of the lists may readily be made, and we shall be able to publish 
with each plant the dates relating to it in each locality. 
Having detailed the views by which we have been guided in drawing up 
the table for annual observations, it remains for us to speak of the dyties of 
the observer. 
Linnzus, who first understood all that was to be deduced from the appli- 
eation of meteorology to the vegetable kingdom, pointed out four periods 
for observation, viz. the foliation, the flowering, the fructification, and the 
fall of the leaf. Other authors have gone further; they have multiplied the 
details. In experiments intended to assume a general character, this ap- 
pears to us neither necessary nor useful; for by heaping up detail upon de- 
tail, these observations cease to be comparable, and thus lose their principal 
utility. Even in the data of Linnzus, there are some which are only applicable 
to a few vegetables. For instance, the foliation and defoliation can hardly 
be determined except on woody plants. It thus appears to us that we must 
confine ourselves to the four data we have pointed out, paying special atten- 
tion to the most important of all, that which alone would in case of necessity 
suffice, viz. the flowering. We leave to each observer the care of noting 
_any peculiarities which may appear to him worthy of notice. 
In the order of observations, two methods may be employed; we may 
either note the plants in their wild state or in their cultivated state. We 
think that the former does not present sufficient facilities, and is subject to too 
much uncertainty, for the observer would be compelled to traverse daily very 
different regions, at great distances apart, and would never be sure of making 
a second observation on the same plant that he had first examined. Where 
in Europe can we find two localities in which the same species of perennial 
plants are to be met with upon a space sufficiently limited for making the 
daily observations? It is impossible for the naturalist to observe daily the 
fields, the woods and the meadows of his country; he must then confine 
himself to approximations. Now that which is essential is, that the daily 
observation of the plants fixed on for comparison should be made in similar 
positions. From this consideration, we are of opinion that these observa- 
tions should be made on individuals planted in an airy garden. The plants 
should neither be sheltered nor exposed to a south wall. As regards trees, 
they should be selected in open fields, but not in woods, which always afford 
very unequal shelter. 
As to the indication of the periods, they should be made, for the foliation, 
when the first leaves burst the buds and become visible; and for the 
flowering, when the anthers are visible; the same will hold good for the 
flowers of the Composite. The period for noting the foliation may offer 
difficulties, from its presenting different phases, which, especially in spring, 
may cause considerable differences. It is requisite, therefore, to have a fixed 
period easily ascertained by every one. We propose to select the moment 
when, from the advance of the vernation, the upper face of the outer leaves 
becomes exposed to the action of the atmosphere and commences its vital 
functions. The fructification should be noted at the time of the dehiscence 
