Species

The Nineteenth Century, a Period of Change 125

held that fossil species merely transformed into later forms.^49 Gillispie notes that

Lamarck was slightly inconsistent on species between 1797 and the statements of

1802 and 1807, but goes on to say

... the inconsistency on species (is) trivial. ... All he did between 1797 and 1800 was

to assimilate the question of animal species—or rather their nonexistence—to that of

species in general. For in Lamarck the word has not lost its broader connotations. It

still carries the sense of all the forms into which nature casts her manifold productions

in all three kingdoms (or rather in both divisions).^50

Lamarck is still indebted to the medieval notion of species as subsidiary divisions
of the summum genus (being) through to the infimae species of rational living things
in the case of humans. In this respect, he was attempting to classify all things as the
outcome of physical molecules and forces, and animal species were just an arbitrary
part of that chain of being. Still, his view of these nominalistic species is that they
are formed out of the generative properties of the life-fluid, and so this is a generative
notion of species in that respect at least.
As to nomenclature, he accepted Linnaeus’ binomial convention, and given there
was no fact of the matter, held that an international agreement should be made to
make names stable.^51 At this stage, Buffon’s objections to the binomial nomencla-
ture have lost the field entirely, when even his own student accepts the practice.
Lamarck’s view of evolution is basically a temporalization of the ladder of nature/
great chain of being. He treated each species as a single lineage that had its own
original spontaneous generation out of non-living material, and which ascended
something like Bonnet’s ladder, although the ladder could branch, as we see in the
famous diagram (Figure 4.1).
The ladder that Lamarck adopted, however, was less direct than Bonnet’s. He
wrote:

I do not mean that existing animals form a very simple series, regularly graded

throughout; but I do mean they form a branching series, irregularly graded and free

from discontinuity, or at least once free from it.^52

Lamarck’s definition was echoed by Isidore Geoffroy Saint-Hilaire (1805–1861),

in 1859, in his Histoire naturelle génerale des règnes organiques:

The species is a collection or a succession of individuals characterized by an ensemble

of distinctive features whose transmission is natural, regular and indefinite in the cur-

rent order of things.^53

(^49) Nordenskiöld 1929, 325.
(^50) Gillispie 1959, 272.
(^51) Nordenskiöld 1929, 326.
(^52) La ma rck 1914; diagram from 179, quote from 37.
(^53) Quoted in Lherminer and Solignac 2000, 156. The French is
(^) L’espèce est une collection ou une suite d’individus caractérisés par un ensemble de traits dis-
tinctifs dont la transmission est naturelle, régulière et indéfinie dans l’ordre actuel des choses.
[Saint-Hilaire 1859, 437, italics original]