304 LAMARCK, HIS LIFE AND WORK 
to those which have given origin to these new indi- 
viduals. 
‘These are the two fundamental truths which can 
be misunderstood only by those who have never 
observed or followed nature in its operations, or only 
by those who allow themselves to fall into the error 
which I have combated. 
“Naturalists having observed that the forms of the 
parts of animals compared with the uses of these 
parts are always in perfect accord, have thought that 
the forms and conditions of parts have caused the 
function; but this is a mistake, for it is easy to 
demonstrate by observation that it is, on the contrary, 
the needs and uses of organs which have developed 
these same parts, which have even given origin to 
them where they did not exist, and which conse- 
quently have given rise to the condition in which we 
observe them in each animal. 
“If this were not so, it would have been necessary 
for nature to have created for the parts of animals as 
many formsas the diversity of circumstances in which 
they have to live had required, and that these forms 
and also the circumstances had never varied. 
“ This is certainly not the existing order of things, 
and if it were really such, we should not have the 
race-horses of England; we should not have our great 
draft horses, so clumsy and so different from the first 
named, for nature herself has not produced their 
like; we should not, for the same reason, have terrier 
dogs with bow legs, greyhounds so swift in running, 
water-spaniels, etc. ; we should not have tailless fowls, 
fantail pigeons, etc.; finally, we could cultivate the 
wild plants as much as we pleased in the rich and 
fertile soil of our gardens without fearing to see them 
change by long culture. 
“For a long time we have felt’ the force of the 
saying which has passed into the well-known proverb— 
habits form a second nature. 
