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Fresh News on Earthworms . 
[February, 
P. E. Muller combats an objedtion which has been brought 
forward, — to wit, that worms cannot effedt very great changes 
in the subsoil. As Darwin admits, they live chiefly in the 
upper stratum of the soil, and only retire lower down in 
severe cold or in prolonged dry weather. To this Muller 
replies that the smaller earthworm (L. communis) frequents 
the upper layer of soil, in which it is not unfrequently frozen 
up in a hard winter ; but that the larger species, as is main- 
tained also by Hensen, works in the subsoil, and rarely visits 
the surface except in mild rainy nights. 
The importance of worm-tubes in aiding the penetration 
of the roots of plants into the soil has also been called in 
question, chiefly on the faith of observations which are not 
quite to the point. Suppose we fill a pot with earth or sand, 
quite free from worms, and introduce a plant ; its roots will 
quickly make their way downwards. But such soil or sand 
is comparatively loose and porous. In the fields and gardens 
the soil, even where it is within the adtion of culture, is 
relatively compadt, and below the reach of the plough or the 
spade it is very dense indeed, almost impenetrable to roots. 
Thus the above-mentioned experiment is illusory. It is also 
proved by diredt observation that the existing tubes or chan- 
nels are preferentially utilised by the roots of plants. Thiel, 
to whose researches we have referred above, admits that the 
roots chiefly penetrate down into the substratum by means 
of such channels, but he doubts whether they derive any 
important share of nutrition from the subsoil, as they do 
not touch the sides of the tubes very closely, but often seem 
to hang in them loosely suspended. 
But Muller shows, in reply, that the minute capillary 
rootlets are most adtive in the absorption of food-matters, 
and these are particularly abundant in the tubes in the sub- 
soil, where they meet with favourable conditions for growth, 
such as an equable temperature, an unexhausted soil, a 
moist air, rich in carbonic acid and space for undisturbed 
growth. The capillaries not merely spread themselves over 
the sides of the tubes, but make their way into minute chinks 
and apertures. 
Another important feature is here brought prominently 
forward by Prof. Muller — the underground dew. In the 
severe winter of 1879-80 he made the following observation : 
—After a frost of several weeks uninterrupted duration the 
frozen stratum was dug through. Immediately below it 
was a moist subsoil of from 1 to 2 feet in thickness, but on 
penetrating still lower down the earth was again drier. 
The presence of the moisture can be accounted for only on 
