It was not my fault that I had to follow Herr Duhring into realms where at best I can only claim to be a dilettante. In such cases I have for the most part limited myself to putting forward the correct, uncontested facts in Opposition to my adversary's false or distorted assertions. This applies to jurisprudence and in many instances also to natural science. In other cases it has been a question of general views connected with the theory of natural science — that is to say, a field where even the profession al scientific investigator is compelled to pass beyond his own speciality and encroach on neighbouring territory — territory on which his knowledge is, therefore, as Herr Virchow has admit ted, just as superficial as any of ours. I h0pe that in respect of minor inexactitudes and clumsinesses of expression, I shall be granted the same indulgence as is shown to each other by writers in this domain.