xiii 



of that city Dr. Waller found agreeable companionship. He was elected a 

 Member of the Societe de Physique et d'Histoire Naturelle, and again 

 applied himself with zeal to scientific work. Having been appointed to 

 deliver the Croonian Lecture before the Royal Society in the spring of 

 1870, he made a short visit to London for that purpose. The subject was 

 "On the Results of the Method introduced by the Author of investigating 

 the Nervous System, more especially as applied to the elucidation of the 

 Functions of the Pneumogastric and Sympathetic Nerves," and it appears 

 to have been his last work. He had for several years been subject to 

 attacks of angina pectoris, and the accession of a fit of more than usual 

 severity caused his death on the 18th of September, 1870. 



Whilst Dr. Waller's researches and discoveries concerning the nervous 

 system constitute his most conspicuous claim to distinction as a man of 

 science, he successfully took up other subjects of physiological inquiry. 

 As especially worthy of note may be mentioned his observations on the 

 escape of white blood-corpuscles from within the small vessels*. This 

 remarkable fact had been already pointed out by Dr. William Addison, and 

 its relation to the nutrition of tissue, as well as to secretion, inflammation, 

 and suppuration, instructively discussed by him. Dr. Waller described 

 the corpuscles as actually piercing the wall of the containing vessel, as if by 

 some softening or solvent operation. The subject has again been brought 

 forward by Dr. Colmheim of Breslau, to whom his countrymen are for 

 the most part in the habit of assigning the discovery. 



Dr. Waller was endowed with a remarkable aptitude for original investi- 

 gation. Quick to perceive new and promising lines of research, and happy 

 in devising processes for following them out, he possessed consummate 

 skill and address in experimental work. During his early studies in Paris 

 he had paid much attention to physical science, and this stood him in good 

 stead in his future investigations. By those who knew him personally, he 

 was much esteemed for his moral qualities, as well as for his intellectual 

 endowment. His sudden death, before he had completed his fifty-fourth 

 year, whilst the cause of poignant grief to his relatives and friends, must 

 also be accounted a serious loss to physiological science. 



The Rev. William Venables Vernon Harcourt, M.A. Oxon., 

 was born in June 1789, close to the ancient home of his family at Sud- 

 bury, in the Rectory House, then occupied by his father, the Hon. and 

 Rev. Edward Venables Vernon, who became Bishop of Carlisle, and after- 

 wards Archbishop of York, and took the name of Harcourt on acceding 

 to the property of the deceased Earl. Mr. Harcourt, the fourth son in a 

 family of sixteen children, had the advantage of his father's instruction, 

 and did not proceed to a public school. 



His first destination was for the Navy, in which he served for five years ; 

 but then his literary tastes and predilection for the church prevailed, and 



* Phil. Mag. 184G. 



