THE PRINCIPLES OF BOTANY. 
369 
the next by a crop of luxuriant grass, to whose superior 
height and dark colour is due the appearance of the ring 
.itself. 
“Now, it was argued, upon the De Candollean theory, that 
the excretions of the fungus were in the highest degree inju- 
rious to its subsequent development on the same spot ; but 
that, on the other hand, they were particularly favorable to 
the growth of the grass which followed them. It may easily 
be seen that this explanation is abundantly sufficient for 
every circumstance of the case, if the theory of De Candolle as 
to the excretions of plants were generally tenable. 
“ It is needless for me to remark, however, that this theory 
has been abandoned by most vegetable physiologists, and has 
lately met distinct confutation from the laborious investiga- 
tions undertaken by Dr. Daubeny on the rationale of the 
rotation of crops. It becomes, then, necessary to seek some 
other explanation for the formation of the fairy rings. In 
the spring of this year (1846) it occurred to me to make a 
chemical examination of these fungi, with the hope of throw- 
ing light upon their peculiar growth; and I was favoured 
with an excellent opportunity of making this examination 
from several magnificent rings growing on the pasture land 
surrounding the Agricultural College.” Now, we have reason 
to know these rings, as they afforded us many a meal of most 
delicious mushrooms, and always about the first or second 
week in May, and we ascertained them to be the true St. 
George's Mushroom, Agaricus gambosus, referred by Dr. 
Badham and others to A. prunulus, and called by the French 
moucheron or mousseron , from its often growing in poor 
mossy pastures. 
It was this species, then, which was analysed by Professor 
Way, and we here give ash analyses of the fungus, and also 
of the grass from some of the fairy rings. 
Ash Analyses by J. 
T. Way. 
Fungus. 
Grass. 
Silica ..... 
. 1-09 ... 
16-10 
Lime 
. 1-35 ... 
10-47 
Magnesia .... 
. 2-20 ... 
2-49 
Peroxide of Iron . 
. trace . . . 
293 
Phosphoric Acid . 
. 29-49 ... 
6-54 
Sulphuric Acid 
Carbonic Acid 
. 1-93 ... 
5 40 
. 3-80 ... 
12-47 
Potash 
. 55-10 
35-23 
Soda 
. 3-32 ... 
none 
Chloride of Sodium 
. 0-41 ... 
5-79 
98-G9 
97-42 
