Generosity, self-sacrifice, kindliness even to unknown strangers, cost not the least effort to the father and son, but seemed to them the most natural thing possible. Just as their little house at Arbois was transformed by a ray of the ideal, the broken down walls of the old Ecole Normale--then a sort of annexe of the Louis Le Grand college, and looking, said Jules Simon, like an old hospital or barracks--reflected within them the ideas and sentiments which inspire useful lives. Joseph Pasteur wrote (Nov. 18, 1843): “The details you give me on the way your work is directed please me very much; everything seems organized so as to produce distinguished scholars. Honour be to those who founded this School.” Only one thing troubled him, he mentioned it in every letter. “You know how we worry about your health; you do work so immoderately. Are you not injuring your eyesight by so much night work? Your ambition ought to be satisfied now that you have reached your present position!” He also wrote to Chappuis: “Do tell Louis not to work so much; it is not good to strain one’s brain. That is not the way to succeed but to compromise one’s health.” And with some little irony as to the cogitations of Chappuis the philosopher: “Believe me, you are but poor philosophers if you do not know that one can be happy even as a poor professor in Arbois College.” Another letter, December, 1843, to his son this time: “Tell Chappuis that I have bottled some 1834 bought on purpose to drink the health of the Ecole Normale during the next holidays. There is more wit in those 100 litres than in all the books on philosophy in the world; but, as to mathematical formulæ, there are none, I believe. Mind you tell him that we shall drink the first bottle with him. Remain two good friends.” Pasteur’s letters during this first period at the Normale have been lost, but his biography continues without a break, thanks to the letters of his father. “Tell us always about your studies, about your doings at Barbet’s. Do you still attend M. Pouillet’s lectures, or do you find that one science hampers the other? I should think not; on the contrary, one should be a help to the other.” This observation should be interesting to a student of heredity; the idea casually mentioned by the father was to receive a vivid demonstration in the life-work of the son. CHAPTER II 1844--1849