28 THE LIFE OF PASTEUR 



the domain of science. And yet, thanks to the saccharimeter , 

 which is a polarizing apparatus, a manufacturer can ascertain 

 the quantity of pure sugar contained in the brown sugar of 

 commerce, and a physiologist can follow the progress of 

 diabetes. 



Chappuis, who knew what powers of investigation his friend 

 could bring to bear on the problem enunciated by Mitscherlich , 

 thought with regret that the prospect of such examinations as 

 that for the licence and for the aggregation did not allow Pasteur 

 to concentrate all his forces on such a special scientific point. 

 But Pasteur was resolved to come back definitely to this sub- 

 ject as soon as he should have become " docteur es sciences." 



When writing to his father he did not dwell upon tartrate and 

 paratartrate ; but his ambition was palpable. He was ever 

 eager to do double work, to go up for his examination at the 

 very earliest. " Before being a captain," answered the old 

 sergeant-major, " you must become a lieutenant." 



These letters give one the impression of living amongst 

 those lives, perpetually reacting upon each other. The thoughts 

 of the whole family were centred upon the great School, where 

 * that son, that brother, was working, in whom the hopes of 

 each were placed. If one of his bulky letters with the large 

 post mark was too long in coming, his father wrote to reproach 

 him gently : " Your sisters were counting the days. Eighteen 

 days, they said! Louis has never kept us waiting so long! 

 Can he be ill? It is a great joy to me," adds the father, " to 

 note your attachment to each other. May it always remain so." 



The mother had no time to write much ; she was burdened 

 with all the cares of the household and with keeping the books 

 of the business. But she watched for the postman with a 

 tender anxiety increased by her vivid imagination. Her 

 thoughts were ever with the son whom she loved, not with a 

 selfish love, but for himself, sharing his happiness in that he 

 was working for a useful career. 



So, between that corner in the Jura and the Ecole Normale, 

 there was a continual exchange of thoughts ; the smallest inci- 

 dents of daily life were related. The father, knowing that he 

 should inform the son of the fluctuations of the family budget, 

 spoke of his more or less successful sales of leathers at the 

 Besancon fair. The son was ever hunting in the progress of 

 industry anything that could tend to lighten the father's heavy 

 handicraft. But though the father declared himself ready to 



