108 THE EXTENSION OP THE PRINCIPLE. 
from the volva, was four days. Extraordinary as 
this rapidity may appear, I believe it to he far 
surpassed by other plants of this family, as I was 
informed by Lady Arden, who has paid great at- 
tention to them, that the lives of some were so 
brief as scarcely to allow of sufficient time to 
finish her drawings of them. Marvellous are 
the accounts of the rapid growth of cells in the 
fungi ; but in the above instance it cannot for a 
moment be imagined that there was any actual 
growth of new cells, but merely an elongation of 
the erectile tissue of the plant. These cases may 
likewise be made available in clearing up the 
confusion which exists in the determination of 
the genera and species of this family. Out of 
one species (Thelephora sulphur ea), according to 
Fries, no less than eight genera have been formed 
in consequence of degeneration or imperfect 
states of growth. 
Lastly, the scientific naturalist will be assisted 
in exploring that debateable ground on the con- 
fines of the animal and vegetable kingdoms, 
where in our present state of ignorance, it is 
often impossible to determine the point at which 
the one ends or the other begins. 
I shall conclude my little work with pointing 
out the application of the same principles, which 
have proved so successful in the growth of plants, 
