274 LAMARCK, HIS LIFE AND WORK 
“The animal which lives a free, wandering life on 
plains, where it habitually exercises itself in running 
swiftly ; the birds whose needs (desoins) require them 
unceasingly to traverse great spaces in the air, finding 
themselves enclosed, some in the compartments of our 
menageries or in our stables, and others in our cages 
or in our poultry yards, are submitted there in time 
to striking influences, especially after a series of re- 
generations under the conditions which have made 
them contract new habits. The first loses in large 
part its nimbleness, its agility; its body becomes 
stouter, its limbs diminish in power and suppleness, 
and its faculties are no longer the same. The second 
become clumsy ; they are unable to fly, and grow more 
fleshy in all parts of their bodies. 
‘Behold in our stout and clumsy horses, habituated 
to draw heavy loads, and which constitute a special 
race by always being kept together—behold, I say, 
the difference in their form compared with those of 
English horses, which are all slender, with long necks, 
because for a long period they have been trained to 
run swiftly: behold in them the influence of a differ- 
ence of habit, and judge for yourselves. You find 
them, then, suchas they are in) some deoreesin 
nature. You find there our cock and our hen in the 
condition we have [made] them, as also the mixed 
races that we have formed by mixed breeding be- 
tween the varieties produced in different countries, or 
where they were so in the state of domesticity. You 
find there likewise our different races of domestic 
pigeons, our different dogs, etc. What are our cul- 
tivated fruits, our wheat, our cabbage, our lettuce, 
etc, etc., if they are not the result of changes which 
ve ourselves have effected in these plants, in chang- 
ing by our culture the conditions of their situation ? 
Are they now found in this condition in nature? 
To these incontestable facts add the considerations 
which I have discussed in my Recherches sur Ices 
