sentences:  Besides Lange, he read the anti-Darwinist botanist Karl Wilhelm von Nägeli's "Mechanisch-physiologische Theorie der Abstammungslehre" (1884) in the period of "Beyond Good and Evil", which became his main source concerning physiology.Nietzsche targeted Social Darwinism, in particular Herbert Spencer, John Stuart Mill and David Strauss (he read all of them, and titled the first "Untimely Meditation" "David Strauss