130 PROCEEDINGS OF THE ACADEMY OF [April, 



research work undertaken }jy Dr. Dixon he found that by intro- 

 ducing old cultures of tubercle liacilli into lower animals a certain 

 degree of immunity was produced, and the publication in the 

 Medical News of Philadelphia on the above date preceded by 

 more than six months a similar announcement and publication of 

 similar work — that of the celebrated Koch of Germany. Koch 

 announced somewhat reluctantly that a substance could be pro- 

 duced that would prevent the growth of the tubercle bacillus in the 

 human system. 



Following Koch's announcement, l^r. Dixon, with authority from 

 American scientific and medical institutions, visited Europe, inter- 

 viewed Koch, Virchow, DuBois-Raymond, and many others. At 

 this time he had the privilege of admission to Koch's own labora- 

 tory. Europe and America were seething with public interest in 

 tuberculosis. Koch's work, as discoverer of the tubercle bacillus 

 and his later work backed by governmental agencies controlling 

 Germany's laboratories, resulted in robbing Dr. Dixon for a long 

 time of that credit of being the first to produce immunity which 

 should have been given him. In recent years American students 

 of tuberculosis have given this credit to Dr. Dixon and to 

 America. 



During the latter part of 1890, while working in his laboratory 

 in the Academy of Natural Sciences, Dr. Dixon developed a tubercle 

 bacillus extract that produces in the lower animals and in human 

 beings that same stimulation toward cure in certain types of the 

 disease that has been found l)y Trudeau, and other students of 

 pulmonary lesions, to be brought about l)y the various forms of 

 tuberculin. Later, this same preparation was found by surgeons 

 to be effective in the treatment of certain glandular and genito- 

 urinary types of tuberculosis and ophthalmologists found it equally 

 helpful in the treatment of ocular types. 



Dr. Dixon's indefatigable energy and originality were no doubt 

 responsible for his selection in 1892 as Executive Curator in the 

 Academy of Natural Sciences, and it is perhaps here and as Curator, 

 that he developed genius for ocular teaching. This experience as 

 Curator, together with his training in hygiene, led to his appointment 

 as a member of the Board of Public Education in 1898. During the 

 greater part of the six year period in the Board of Public Education 

 Dr. Dixon was Chairman of the Committee on Hygiene. It was 

 during this time that the active campaign was conducted for furnishing 

 public school children of the city of Philadelphia with pure drinking 



