20 ANNUAL KEPOET SMITHSONIAN INSTITUTION, 1912. 



HAMILTON LECTURE. 



The third Hamilton fund lecture of the Smithsonian Institution 

 was delivered by Dr. Simon Flexner, of the Eockefeller Institute 

 for Medical Research, in the auditorium of the United States 

 National Museum, February 8, 1912. 



The title of the lecture was " Infection and Recovery from Infec- 

 tion," an investigation to which Dr. Flexner has given especial study 

 for several years. 



In his treatment of this vital and interesting subject the speaker 

 covered a broad field of medical science, and at the same time ex- 

 pressed himself in such a manner as to be intelligible to laymen. 

 Dr. Flexner touched upon the following points : 



The part played by bacteria, protozoa, and submicroscopic para- 

 sites in causing infection was described, and emphasis laid upon the 

 occurrence on the surface of the body of many kinds of disease- 

 producing germs. The manner in which they are excluded by skin 

 and mucous membranes was discussed, as well as their ability to 

 enter the body by these channels when tl^y were imperfect. In this 

 way a variety of diseases is produced, including diphtheria, menin- 

 gitis, and probably infantile paralysis. The germs that enter the 

 body encounter a second and even more efficient set of defenses 

 in the blood with its devouring white corpuscles. When disease 

 appears, in spite of and because of inadequacy in the defensive 

 mechanisms, then the body, under the influence of the parasitic germs, 

 sets about creating new defensive principles through the process of 

 immunization. It is immunization that vaccination produces, which 

 is a protection to smallpox ; and it is through purposive immunization 

 of animals that the curative serums are prepared, that by injection 

 bringing about an artificial and premature cessation of such diseases 

 as diphtheria and epidemic meningitis. The part played by insects 

 in transmitting malaria, yellow fever, typhus fever, and relapsing 

 fever was sketched, and the varying susceptibilities to disease of 

 different races, species, and individuals dwelt on and in part ex- 

 plained, on the basis of known facts of immunity to and virulence 

 of the germ causes of disease. 



The above is the third of the series of Hamilton lectures. In 1871 

 James Hamilton, a retired lawyer of Carlisle, Pennsylvania, 

 bequeathed $1,000 to the Smithsonian Institution, the interest of 

 which was to be appropriated biennially by the secretary for some 

 contribution, paper, or lecture on any scientific or useful subject 

 which he might select. As the sum was somewhat limited to ade- 

 quately carry out the donor's wishes, the interest was allowed to 

 accumulate until the amount was doubled, and the Institution then 

 created a series of lectures, known as the Hamilton Fund Lectures. 



