Let me take leave of you with this practical conclusion, and give my heart freedom to send to my brain a wave of fervent blood, which shall express my enduring gratitude for the reception which you have given me.  Old in years, but young in spirit and energetic aspiration to every high ideal, I tender you my sincere thanks.  As a man and a citizen, I thank you, because these three lectures have been for me a fountain of youth, of faith, of enthusiasm.  Thanks to them I return to the other fields of my daily occupation with a greater faith in the future of my country and of humanity.  To you, young Italy, I address these words of thanks, glad and honored, if my words have aroused in your soul one breath which will make you stronger and more confident in the future of civilization and social justice.