1895. The Speculative Method in Entomology. Trans. Ent. Soc., London, 1895, pp. XLVIII-LXXIII.

Van Hise, C. R.

1902. The Training and Work of a Geologist. Science, N. S., Vol. XVI, pp. 321-334.

Keyes, C. R.

1898. The Genetic Classification of Geological Phenomena. Jour. Geol., Vol. VI, pp. 809-815.

Valuable for its discussion of the criteria used in genetic studies.

Van Hise, C. R.

1904. The Problems of Geology. Jour. Geol., Vol. XII, pp. 589-616; Inter. Cong. Arts and Sciences, St. Louis, Vol. IV, pp. 525-548. 1906.

An excellent discussion of the energy, agent, and process method of investigation. I have seen no similar discussion applied to biological or zoölogical subjects.

Boas, F.