In my book _Socialismo et Criminalita_, published in 1883, and which to-day my adversaries, including M. Garofalo (p. 128 _et seq._), try to oppose to the opinions which I have upheld in my more recent book, _Socialisme et science positive_ (the present work), I have developed two theses: I. That the social organization could not be _suddenly_ changed, as was then maintained in Italy by the sentimental socialists, since the law of evolution dominates with sovereign power the human world as well as the inorganic and organic world; II. That, by analogy, crime could not disappear _absolutely_ from among mankind, as the Italian socialists of those days vaguely hinted. Now, in the first place it would not have been at all inconsistent if, after having partially accepted socialism, which I had already done in 1883, the progressive evolution of my thought, after having studied the systematic, scientific form given to socialism by Marx and his co-workers, had led me to recognize (apart from all personal advantage) the complete truth of socialism. But, especially, precisely because scientific socialism (since [the work of] Marx, Engels, Malon, de Paepe, Dramard, Lanessan, Guesde, Schaeffle, George, Bebel, Loria, Colajanni, Turati, de Greef, Lafargue, Jaures, Renard, Denis, Plechanow, Vandervelde, Letourneau, L. Jacoby, Labriola, Kautsky, etc.) is different from the sentimental socialism which I had alone in mind in 1883, it is for that very reason that I still maintain to-day these two same principal theses, and I find myself in so doing in perfect harmony with international scientific socialism. And as to the absolute disappearance of all criminality, I still maintain my thesis of 1883, and in the present book (Sec. 3), I have written that, even under the socialist regime, there will be--though infinitely fewer--some who will be conquered in the struggle for existence and that, though the chronic and epidemic forms of nervous disease, crime, insanity and suicide, are destined to disappear, the acute and sporadic forms will not completely disappear. At this statement M. Garofalo manifests a surprise which, as I can not suppose it simulated, I declare truly inexplicable in a sociologist and a criminologist; for this reminds me too strongly of the ignorant surprise shown by a review of classical jurisprudence in regard to a new scientific fact recorded by the _Archives de psychiatrie_ of M. Lombroso, the case being the disappearance of every criminal tendency in a woman after the surgical removal of her ovaries. But that the trepanning of the skull in a case of traumatic epilepsy or that ovariotomy can cure the central nervous system and, therefore, restore the character and even the morality of the individual, these are facts that can be unknown only to a metaphysical idealist, an opponent of the positivist school of criminology.