At the moment I can do absolutely nothing with it, and limit myself to the most necessary duty of my lectures; how much happier I would be to be scientifically active, if only I had the necessary mental freshness.
Polo de agora non podo facer absolutamente nada con el, limitándome aos meus deberes coma docente; canto máis feliz sería de estar activo cientificamente, de ter a frescura mental necesaria."