Neisser and neisserian principles in venereology.

I value very highly the honour of having been invited to give the opening address at this centenary celebration of Neisser's birth, but I am very acutely conscious of my defects as an historian and hope that members of the distinguished company here to-night will fill the gaps that are inevitable in my story, because only with your help will the Osler Club honour worthily the memory of a man who used his outstanding abilities in the service of mankind to such a degree and with such success as to entitle him to high prominence in every history of medicine; indeed in every history of social endeavour. My brief stipulates not much biography and restricts me, by my own wish I may say, to only one of the fields in which our hero shone, but in this field I may wander a little from the strictly Neisserian path to comment on contemporary events in venereology which may not perhaps be now familiar to you, but have always seemed to me to be interesting and instructive. For a number of the facts in my condensed biography I am indebted to Neisser's "Beitrage, zur Pathologie und Therapie der Syphilis" (Neisser, 191 la), and to the obituary which appeared in the Lancet (1916) Neisser's birthday was on January 22, 1855,which Icalculate fell ona Monday,whateverthat may have portended. He was the son of a physician, an advantage in respect of family atmosphere which, from personal experience, I have always thought very valuable to a member of our profession. He became M.D. at the age of 22, his thesis being a monograph on diseases due to T. echinococcus, thus disclosing early his taste for precision in instruments of diagnosis, microscopy in particular. He quickly became assistant to Oskar Simon, the Director of the Department of Dermatology in the University of Breslau, and in 1879, 2 years after qualification, at the age of 24, he announced in a preliminary communication (Neisser, 1879), that he had seeningonorrhoealpus certaincocci ofdistinctive