El quince de junio de 1864 Charles Darwin escribe una carta a su amigo, el aventurero Wallace. Esta carta que hoy es la número 4535 del Darwin correspondence Project contiene un párrafo final, marcado como P. S. (Post Scriptum) que dice: P.S. A great gun Flourens has written a little dull book against me  which pleases me much for it is plain that our good work is spreading in France. He speaks of the «engouement» about this book so full…