DECISIVE EXPERIMENTS. 167 



completely vanquished. Those who went into his 

 room found him often bathed in tears. On January 

 18, 1871, he wrote, to the Dean of the Academy 

 of Medicine at the University of Bonn, a letter 

 in which all his grief and all his pride as a 

 Frenchman were displayed, requesting him to with- 

 draw the diploma of German doctor which the 

 Faculty of Medicine of the University had conferred 

 upon him in 1868. Whilst he wrote this letter, 

 which was a cry of patriotism, his son, enrolled as a 

 volunteer, though hardly eighteen years of age, was 

 gallantly doing his duty in the Army of the East. 



