ts in compensation, but does not quote any instances.)

[September 1846].

Have you ever thought of G. St. Hilaire's "loi de balancement" (23/2.
According to Darwin ("Variation of Animals and Plants," 2nd edition,
II., page 335) the law of balancement was propounded by Goethe and
Geoffroy Saint-Hilaire (1772-1844) nearly at the same time, but he gives
no reference to the works of these authors. It appears, however, from
his son Isidore's "Vie, Travaux etc., d'Etienne Geoffroy Saint-Hilaire,"
Paris 1847, page 214, that the law was given in his "Philosophie
Anatomique," of which the first part was published in 1818. Darwin
(ibid.) gives some instances of the law holding good in plants.), as
applied to plants? I am well aware that some zoologists quite reject it,
but it certainly appears to me that it often holds good with animals.
You are no doubt aware of the kind of facts I refer to, such as
great development of canines in the carnivora apparently causing
a diminution--a compensation or balancement--in the small size of
premolars, etc. I have incidentally noticed some analogous remarks on
plants, but have never seen it discussed by botanists. Can you think
of cases in any one species in genus, or genus in family, with certain
parts extra developed, and some adjoining parts reduced? In varieties
of the same species double flowers and large fruits seem something of
this--want of pollen and of seeds balancing with the increased number
of petals and development of fruit. I hope we shall see you here this
autumn.

(24/1. In this year (1847) Darwin wrote a short review of Waterhouse's
"Natural History of the Mammalia," of which the first volume had
appeared. It was published in "The Annals and Magazine of Natural
History," Volume XIX., page 53. The following sentence is the only one
which shows even a trace of evolution: "whether we view classification
as a mere contrivance to convey much information in a single word, or as
something more than a memoria technica, and as connected with the laws
of creation, we cannot doubt that where such important differences in
the generative and cerebral systems, as distinguish the Marsupiata from
the Placentata, run through two series of animals, they ought to be
arranged under heads of equal value."

A characteristic remark occurs in reference to Geographical
Distribution, "that noble subject of which we as yet but dimly see the
full bearing."

The following letter seems to be of