XIX 



even the humblest, followed him with grateful recognition when he 

 appeared at the stations or moved among them. 



Indeed, his life was one of incessant labour and benevolent 

 endeavour to turn to useful ends each new insight into nature which 

 he and others were acquiring. Sympathising with all, seeming to 

 understand the sentiments and interests of all, he was generous 

 as well as just in his judgment of others, yet ever courageous 

 and firm in the assertion of whatever he deemed to be right and 

 true. Indefatigable in the pursuit of truth, he was as able in 

 imparting it. Eloquence, the graces of style, and the mastery of 

 several languages combined to make him a great teacher. Even in 

 his youth he had become conscious that to teach was to learn, and 

 that to learn was the purest of intellectual enjoyments. 



" I was already in correspondence with Bonders," says von Helm- 

 holtz, in a letter to the present writer, " before 1856, when I lived 

 in Konigsberg. He had sent me his physiological treatise on Animal 

 Heat and his handbook on Physiology, and as I had then made the 

 first experiments on the change of form of the crystalline lens in 

 accommodation, he told me about the somewhat earlier experiments 

 made by Cramer in his laboratory. As far as I know, I first made 

 his personal acquaintance during my stay at Bonn, between 1856 and 

 1859. He used to go in summer, with his then already ailing wife, 

 to Cleve, to breathe purer air in that hilly country, as was then the 

 fashion in Holland. From thence he came over to Bonn. I have 

 also paid him a visit of a few days, in Utrecht, at that time, and lived 

 in his house. . . . The loveablcness, openness, and honesty of his 

 character you know I need not portray them to you. We have then 

 and afterwards discoursed very much on scientific questions, as we 

 many times and independently had taken the same problems in hand. 

 He had, in Ophthalmology, the greater experience of patients, and I 

 have learnt much from him in that respect ; but even where it seemed 

 to me that I must maintain my own opinion, I never observed in him 

 the least sign of sensitiveness, or of too great warmth in defending 

 his position. In his way of talking he had then already, as a young 

 man, something of stateliness ; he loved choice expressions, remind- 

 ing one somewhat of the antique eloquence of the French Academy. 

 But he was never prolix, indeed, rather concentrated, in his conversa- 

 tion, and I have always loved to listen to him, though in Germany 

 we are very little accustomed to attend much to the artistic oratorical 

 element in speaking. He was clearly a warm-hearted man with 

 great ideal views, and he thought it his duty to give utterance to 

 these ideal views before the world, and to show them in their height 

 and significance. Moreover, he was aware of- his capacity of im- 

 pressing this with great force upon his auditory. Very beautiful in 

 this respect was his last speech in handing over the Graefe Medal at 



