XVII 



and Lydekker's ' Introduction to the Study of Mammals (1891), but 

 he mainly concentrated himself upon a work which, if completed, 

 would have ranked as one of the most thorough and exhaustive 

 treatises on any group of mammals in existence. The publication of 

 his 'Monograph of the Insectivora, Systematic and Anatomical,' 

 commenced in 1882, was unhappily interrupted before it was quite 

 finished by a slow, insidious, and ultimately fatal illness, which com- 

 pelled him not only to give up his position as an army surgeon, but 

 also to abandon all scientific work, and to live for several years in 

 complete retirement, gradually failing in strength until death inter- 

 vened on November 26, 1895. Thus was lost to science one who, in 

 his too short career, had proved himself an industrious, careful, and 

 conscientious worker, and whose upright and amiable character had 

 won for him the sincere esteem of all who were brought into personal 

 contact with him. He was elected a Fellow of the Royal Society 

 in 1883, and was a corresponding member of the Academy of Natural 

 Sciences of Philadelphia and of the Biological Society of Washington. 



W. H. F. 



Hermann von Helmholtz was born in Potsdam, on August 31, 

 1821. His father was a Professor of Literature in the Gymnasium of 

 that town. His mother, whose maiden name was Caroline Penne, 

 was of English descent, and was connected with the founder of 

 Pennsylvania. For the first seven years of his life he was delicate, 

 but during these early troubles, and throughout his boyhood, his 

 parents tended him with the most unremitting attention and affec- 

 tion. 



In the well known * Autobiographical Sketch,' contained in an 

 address delivered in 1891, on the occasion of the attainment of his 

 seventieth year, an interesting account of his mental development 

 was given by von Helmholtz himself. 



He went to school at the Gymnasium in which his father taught? 

 and, as he himself thought, found unusual difficulty in mastering 

 and remembering " disconnected things," such as " irregular gram- 

 matical forms, and peculiar terms of expression." " To learn prose 

 by heart was martyrdom." "Whether this defect was or was not as 

 great as von Helmholtz sifpposed, he appears to have had an unusually 

 good memory for things which he cared about, and to have had the 

 gift of caring chiefly for the best. He could repeat whole " books 

 of the Odyssey, a considerable number of the odes of Horace, and 

 large stores of German poetry." 



In the study of science, " the laws of phenomena " afforded the 

 conecting link which his memory needed. He gained his earliest 

 knowledge of geometry by playing with wooden blocks, but the first 

 fragments of physics which he learned in the Gymnasium exerted 



vol. lix. d 



