[Oration held at the occasion of the bestowal of the honorary doctor's degree to M. H. J. P Thomassen by the Senate of the University of Groningen on 21 June 1905].

Hamburger, former colleague of Thomassen at the Veterinary School in Utrecht, and then professor of Physiology in Groningen, reviewed the career and merits of Thomassen. After graduation as veterinary surgeon (Utrecht 1869) Thomassen developped a succesful veterinary practice in Maastricht, in the neighbourhood of which city he was born. He attracted attention by his publications in foreign veterinary journals. In 1881 he was appointed as clinical teacher at his old school. Next to internal medicine, his teachings encompassed diagnostics, general therapy, pharmacology and history of veterinary medicine. His inquiring spirit led him to manifold investigations. His therapy of bovine actinomycosis by potassium-iodine (1885) was that succesful that the American government set up a committee of inquiry, that only could confirm the effectiveness. The field of nervous diseases in domestic animals was hardly developed at his time. His broad and systematic research on the pathology and etiology of laryngeal hemiplegia was masterly executed. It was followed by a great number of investigations on the disorders of the peripheral and central nervous system. He made himself familiar with the necessary technics of microscopical pathological investigation. He devoted his attention also to the emerging field of bacteriology and its clinical implications. He studied endocarditis acuta in the horse, bacterial nephritis in calves, chronic nephritis in horses, but especially tuberculosis. His transmission experiments showed reciprocal infectivity of tuberculosis between animals and man. Therefore, he could rightfully oppose Robert Koch, who proclaimed the non-infectivity of bovine tuberculosis for humans at the International Tuberculosis Congress in London of 1901. The author draws a contrasting picture of Thomassen's results with the poor surroundings at the Veterinary School in his days and the shortage of tools that he had at his disposal. His true genius and original mind could overcome those difficulties. His wide range of talents manifested itself in his cultivation of the art of singing, his language abilities and his historical writings on Dutch national history of the 16th century and on veterinary medicine in classical Antiquity. He was an excellent teacher and very much appreciated as speaker at international congresses.