LAMARCK’S THEORY OF EVOLUTION 235 
faculties, etc., is entirely the result of circumstances 
to which the race of each species has been subjected 
by nature. 
“T could prove that it is not the form either of the 
body or of its parts which gives rise to habits, to the 
mode of life of animals, but, on the contrary, it is 
the habits, the mode of life, and all the influential 
circumstances which have, with time, made up the 
form of the body and of the parts of animals. With 
the new forms new faculties have been acquired, and 
gradually nature has reached the state in which we 
actually see her”’ (pp. 12-15). 
He then points out the gradation which exists from 
the most simple animal up to the most composite, 
since from the monad, which, so to speak, is only an 
animated point, up to the mammals, and from them 
up to man, there is evidently a shaded gradation in 
the structure of all the animals. So also among the 
plants there is a graduated series from the simplest, 
such as AZucor virtdescens, up to the most complicated 
plant. But he hastens to say that by this regular 
gradation in the complication of the organization he 
does not mean to infer the existence of a linear series, 
with regular intervals between the species and genera: 
“« Such aseries does not exist ; but I speak of a series 
almost regularly graduated in the principal groups 
(asses) such as the great families; series most as- 
suredly existing, both among animals and among 
plants, but which, as regards genera and especially 
species, form in many places lateral ramifications, 
whose extremities offer truly isolated points.” 
This is the first time in the history of biological 
science that we have stated in so scientific, broad, 
