174 
ARE SOILS ENRICHED, IMPOVERISHED, [Part III- 
planta socialis assists and is assisted by bis 
fellow planta socialis; that there is, as Liebig 
expresses it, “ a mutual interchange of nutri¬ 
ment between the plantsthat each battens 
on his neighbour’s excretions; and that each is 
relieved by his neighbour from his own, to him¬ 
self, poisonous excretions, in which an all-wise 
Providence has thought fit to envelope the roots 
of every vegetable. When will these great the¬ 
orists persuade practical farmers to sow social 
plants with their crops, or even not to eradicate 
these social intruders ? Charlock has sworn an 
eternal friendship with turnips. The poppy and 
cornflower with corn-crops. Practical farmers 
nip all this vegetable affection in the bud, and 
forbid their crops the society of any followers or 
strangers whatever; though, alas! how often, 
like the parents of Pyramus and Thisbe, “vetuere 
quod non potuere vet are.” In this case the 
crops and the weeds ripen their seeds simul¬ 
taneously (which is one constant cause of pro¬ 
pinquity, or sociability, in cultivated annuals); 
and as they are threshed and re-sown by our 
own hands, their re-union is certainly not ef¬ 
fected by any choice of theirs. But ask the 
farmer if these social plants benefit his crops, 
and ask the physiologist how clean crops and 
