230 THE LARCH. 
Another source, we believe, arises from the roots resting on 
a retentive subsoil. A ferruginous crust or subsoil which 
retains water is generally found to yield diseased larch tim- 
ber. During winter, when the tree is in a dormant state, its 
small fibres retain life in stagnant water for a considerable 
time ; but in the months of August and September, the season 
at which floods frequently occur, the spongioles are in an active 
state, and stagnant water has been known to rot the weakest 
fibres in the course of two days. Excessive moisture is thus 
calculated to commence the disease in woods standing on 
retentive subsoil, where it is imperfectly drained. The rot in 
larch no doubt arises at first from a decayed or injured root, 
and whatever tends to damage a fibre should be avoided. 
It is generally admitted by vegetable physiologists that a 
perfect root with its spongioles in a healthy state has the 
power, at least to a great extent, of selecting the food adapted 
to the plant; but let the spongioles become mutilated or de- 
cayed, and they possess that power no longer, but absorb any 
fluid with which they come in contact. 
The rot is sometimes met with in young woods in the best 
description of larch soil. It appears in thinning, when the 
trees are no stronger than prop-wood ; this is commonly the 
result of planting very large plants with mutilated roots. 
I lately observed, on some fine specimens of the larch, about 
forty-five years’ growth, being removed from a mixed planta- 
tion of larch and oak, that the timber was generally quite 
sound and healthy, pumping was of very rare occurrence, not 
more than one or two instances of it in an acre on the aver- 
age, and where it did occur it was generally in the centre of 
the trunk. I saw, however, on one of the largest roots near 
the outside, which yielded one of the heaviest trunks on the 
ground, that the disease had taken possession of one side only, 
forming a bulge or swelling which enclosed the vacuity in the 
timber ; the stump left in the ground showed that the ailment 
arose purely from one main root. To find out if possible the 
source of the disease, I had the root laid open by excavating 
the ground for the distance of a few yards, where it was 
