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194 INTERNATIONAL BOTANICAL CONGRESS. 
think of the Crystal Palace, of Chatsworth, and of the humble gardener 
who became a great architect. If we visit the beautiful establishment 
at Kew, we see everywhere around us proofs of the indefatigable activity 
of Sir William Hooker. Lastly, if we ask the origin of the garden of 
the Royal Horticultural Society at Kensington, we are told it is only a 
development of that at Chiswick, where Lindley stood pre-eminent 
by his knowledge and his energy; and of that society where botanists 
of my age found in their youth such valuable encouragement in their 
studies. 
The names of Sir William Hooker and of Dr. Lindley, thanks to - 
their special works, will ever remain distinguished in science. These 
two botanists have, moreover, been directors of horticultural journals, 
and of great horticultural establishments, and since their influence has 
been so fully acknowledged by practical men, I shall have little trouble 
in showing that science is as useful to horticulturists as horticulture is 
to botanists,—and this will form the second part of my discourse. 
2. The Advantage of Botany to Horticulture. 
The principles of vegetable physiology are what horticulturists and 
agriculturists usually study in books on botany. They do not always 
find direct answers to their questions ; but they can draw from them 
certain rules, certain ways of experimentalizing and reasoning, which 
saye them from falling into many errors. Should some ridiculous idea 
be promulgated by some ignoramus or charlatan, it is by an appeal to 
the general rules of physiology that a practical man may at once reject 
them, or, at least, hold them in distrust. On the contrary, innova- 
tions, if in harmony with the principles, may be, and I will even say, 
ought to be readily accepted. 
Do not let us put too much faith in the lucky results of experiments 
made absolutely by chance. It is with some of these experiments as 
with dreams and presentiments,—if they come true once in a thousand 
times they are talked about, otherwise they are passed over and for- 
gotten. Besides, it must be said, men nearly always are guided by 
theories ; but the theories of the ignorant are often absurd and without 
foundation, whilst those of educated men are based on probabilities, or 
on an accumulation of facts. 
- Conjointly with physiology, botanical geography shows the distribu- 
tion of phate all over the globe; their struggle with the elements, their 
