as in the case of the bears, of herbivorous
adaptation, as in the case of the horses, or myrmecophagous adaptation,
as in the case of the anteaters, are all secondary" (_loc. cit._, pp.
23-4).

We have now reached the end of our historical survey of the problems of
form. What the future course of morphology will be no one can say. But
one may hazard the opinion that the present century will see a return to
a simpler and more humble attitude towards the great and unsolved
problems of animal form. Dogmatic materialism and dogmatic theories of
evolution have in the past tended to blind us to the complexity and
mysteriousness of vital phenomena. We need to look at living things with
new eyes and a truer sympathy. We shall then see them as active, living,
passionate beings like ourselves, and we shall seek in our morphology to
interpret as far as may be their form in terms of their activity.

This is what Aristotle tried to do, and a succession of master-minds
after him. We shall do well to get all the help from them we can.

[519] See E. B. Wilson's masterly book, _The Cell in
Development and Inheritance_, New York and London, 1900.

[520] _Q.J.M.S._, xxvi. 1886.

[521] _Wood's Holl Biological Lectures_ for 1893.

[522] _Arch. f. Ent.-Mech._, i., pp. 380-90, 1895.

[523] _Beitraege zur Kritik der Darwinschen Lehre_,
Leipzig, 1898.

[524] See E. B. Wilson, "The Embryological Criterion of
Homology," _Wood's Holl Biological Lectures_, Boston,
pp. 101-24, 1895; Braem, _Biol. Centrblt._, xv., 1895;
T. H. Morgan, _Arch. f. Ent.-Mech._, xviii.; J. W.
Jenkinson, _Mem. Manchester Lit. Phil. Soc._, 1906, and
_Vertebrate Embryology_, Oxford, 1913; A. Sedgwick,
article "Embryology" in _Ency. Brit._, p. 318, vol. xi.,
11th Ed. (1910).

[525] For a detailed treatment of this important point see
the remarkable volume of E. Schulz (Petrograd),
_Prinzipien der rationellen vergleichenden Embryologie_,
Leipzig, 1910.

[526] "La Poecilogonie," _Bull. Sci. France et Belgique_,
xxxix., pp. 153-87, 1905.

[527] _Un probleme de l'evolution. La loi biogenetique
fondamentale_, Paris and Montpellier, 1908.

[528] _Vergleichung des Entwickelungsgrades der Organe zu
verschiedenen Entwickelungszeiten bei Wirbeltieren_,
Jena, 1891.

[529] Quoted by Keibel, _Ergebn. Anat. Entwick._, vii., p.
741.

[530] "Studien zur Entw