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Obituary Notices of Fellows deceased. 



remarkable series of researches in chemo-therapy which culminated in his 

 discovery of salvarsan in 1910. He died suddenly in August, 1915, in the 

 full height of his mental activity and vigour. 



Ehrlich's earlier work, belonging as it did to no distinct branch of science, 

 did not for a time receive the attention it merited, but the importance of 

 his researches on immunity could not be ignored, though his views involved 

 him in much controversy, sometimes not devoid of bitterness. It was, 

 however, his great therapeutic discovery that set him on a pinnacle in his 

 own country, and from this time he was acclaimed as one of the greatest. The 

 recognition of his work in this and other countries was a great gratification 

 to him. He was Croonian Lecturer in 1900, he gave the Harben Lectures in 

 1907, and he delivered a remarkable address on chemo-therapy at the Inter- 

 national Medical Congress in London in 1913, meeting with an ever-growing 

 welcome and appreciation. In 1908 he was awarded, jointly with Metchnikoff, 

 the Nobel prize, and in connection with this he delivered an address on " The 

 Partial Functions of the Cell," which contains the latest development of his 

 views on the receptor-apparatus of cells. 



Although Ehrlich thus worked in and enriched various fields of science, it is 

 not difficult to trace a unifying principle throughout his investigations. One 

 subject led to another ; his work as a whole is an evolution. This leading 

 principle is the affinity of the constituent molecules of living matter for 

 various chemical substances brought into relationship with them. To treab 

 the substance of cells according to the principles of the organic chemistry of 

 the day did not lack in boldness, and if we waive the question as to the 

 correcttiess of theory, we must admit that the results were striking. This 

 principle in EhrHch's work is seen first when he was a student of medicine, 

 in connection with a paper on lead poisoning by Heubel, who claimed that 

 the organs in which the lead accumulated had also after death the property 

 of fixing the metal. Ehrhch recognised the difficulty of this problem of 

 fixation and distribution by quantitative methods, and conceived the idea of 

 using a coloured substance for the study of the problem, introducing fuchsiu 

 for the purpose with success. The period of his work at Berlin was largely 

 occupied by this question of selective affinity, and though it supplied methods 

 of great value to the histologist, one must recognise that a dye was employed 

 simply as a suitable means in the study of the larger question. His duties in 

 connection with clinical medicine, though not in themselves attractive to 

 him, supplied problems of interest and also material for research, and in this 

 way many of his investigations at the time came to be in connection with 

 diseases of the blood. 



By his method of " Farbenanalyse " he was for the first time able to 

 recognise and differentiate classes of cells. He discovered the specific granu- 

 lations of the leucocytes, classified these cells, and especially insisted on the 

 fundamental difference between the lymphoid and myeloid tissues. It is still 

 a matter of dispute in what sense this difference is to be accepted, but there 

 is no doubt as to the fundamental importance of Ehrlich's observations both 



