Comments on effects of prussic acid on different individuals of the same species and other physiological research by WP.

Provides information about his studies in Edinburgh and Cambridge and qualifications he had for Beagle voyage. Describes influence of R. E. Grant and J. S. Henslow.

Comments on WP’s biographical article on CD. Asks him to thank O. F. Peschel for his present of the publication [Das Ausland 2 Apr 1870].

Is sending copy of Descent.

Thanks for copy of WP’s book [Die Blutkrystalle (1871)].

Discusses shape of external ear.

Obliged for letter about human ear. Comments on ears and on E. R. Lankester’s idea about the ear-lobe.

Discusses inheritance.

Has WP heard of Douglas Spalding’s experiments of blindfolding chickens ["Instinct – with original observations on young animals", Rep. BAAS 42 (1872): 141–3]?

Thanks WP for election [as honorary member of the Medicinisch-Naturwissenschaftliche Gessellschaft zu Jena].