Part III.] OR POISONED BY VEGETABLE GROWTH? 
173 
In reference to this, Richard writes: — “This 
unctuous matter was the product of a kind of 
excretion performed by the roots. To this 
matter, which, as we have said, is different in 
different species of plants, the sympathies and 
antipathies which certain plants have towards 
each other have been attributed. It is well 
known, in fact, that certain plants have, as it 
were, a kind of liking to each other, and con¬ 
stantly live together. These are named social 
plants.” 
And again: “ Roots also excrete, by their 
slender extremities , certain fluids, which are in¬ 
jurious or useful to the plants which grow in 
their vicinity; and in this manner the likings 
and antipathies of certain plants may be ac¬ 
counted for.” 
In any branch of science other than vegetable 
physiology it would be considered a mechanical 
difficulty to pass the two contrary currents of 
absorption and excretion through the same ca¬ 
pillary tubes of the “ slender extremities,” to 
say nothing of the chemical difficulty of passing 
the food and poison through the same conduits. 
But what nonsense can be too nonsensical for 
vegetable physiologists! 
De Candolle, Liebig, &c. believe that each 
