Later Schleich would recall: In the year 1864, Graefe was a guest in my father's house during the historic conference of biologists, at which Darwin, Haeckel, and Virchow were the mutually hostile protagonists.

In 1887, Schleich received his doctorate at the University of Greifswald, and stayed there as an assistant two years more; a period of time where Virchow spoke to him about his antidarwinist views.

[citation needed] The book laid the commercial foundations of the German editor Ernst Rowohlt, and was translated into English with the title "Those Were Good Days".

The stubborn adherence to prejudices, traditions and comfortable habits is but a general human obstacle to progress, no matter whether it is expressed at Church, the State, or the laboratory.

[12]He maintained that "Darwinism by no means overturns the concept of creation",[13] and, in his Memoirs (1920), he expressed a strong belief in the existence of God[14] and the relation of this to science, stating that this was one of the main objects of his physiological studies: It has always been my endeavour to compare the intellectual processes with the action of an electrical apparatus of marvellous precision.

But I have never denied that this is only one, and perhaps the most interesting mode of considering the most sacred miracle of the soul; and not an unveiling, by a theory of cognition, of its metaphysical home and its God-given function... What I most passionately desire is to turn men away from the barren desert of materialism, and compel them to recognize the governance of quite other powers than capital, politics, the struggle for existence, and the laws of inheritance.

The miracles are too many, and one of the noblest tasks of science is to show that the most everyday things, the most apparently familiar, the simplest processes, contain a chain of amazing revelations and mysteries.