I wish I could even make any return for all your facts, views, and suggestions.
LETTER 23.

TO J.D.

HOOKER.
(23/1.

The following extract gives the germ of what developed into an interesting discussion in the "Origin" (Edition I., page 147).

Darwin wrote, "I suspect also that some cases of compensation which have been advanced and likewise some other facts, may be merged under a more general principle: namely, that natural selection is continually trying to economise in every part of the organism." He speaks of the general belief of botanists 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.