Bacteriology 397 



of human beings, in which the oxygen is less firmly bound; nor need 

 it, even should the micro-organism be found sometimes to survive 

 in these fluids." 



From these discoveries it is now certainly well established that 

 acute anterior poliomyelitis is an infectious disease, occasioned by 

 a minute anaerobic organism, of globoid form, capable of resisting the 

 bactericidal effects of glycerin for months, and capable of passing 

 through the pores of a Berkefeld filter. When nervous or other 

 tissue containing it, or pure cultures of it, are introduced into the 

 nervous tissue or into the subcutaneous tissues of certain animals, 

 of which the monkey is the chief one, the disease is readily induced. 



The mode of transmission remains to be discussed. From the 

 failure of those who .continued the insect experiments to achieve 

 continued success, and because of the short time the infectious agents 

 are in the blood — only the first few days — and the small number that 

 seem to be there, it is well to assume that insects play a doubtful 

 r61e, unless it be the common house-fly, Musca domestica. 



Flexner and Clark* have shown that when the virus is introduced 

 into the upper nasal mucosa in monkeys its propagation can be 

 followed from the olfactory lobes of the brain to the medulla ob- 

 longata and spinal cord. Since the virus can thus find its way from 

 the nasal mucosa to the deeper nervous tissues, they hold the opinion 

 that it is through this avenue that infection commonly takes place. 



During the disease, the infectious agents are upon the nasal 

 mucosa, they may be discharged from the surface into the atmos- 

 phere, and inhalation by others may be the means of infection. It 

 is also not impossible that house-flies first visiting the nose of an 

 infected sleeping child, and then some other sleeping child, may carry 

 the organisms. 



One attack of the disease confers immunity, and experimental 

 immunization can be effected by a succession of doses beginning 

 with great dilutions and ascending to greater concentrations like 

 the Hogyes method in rabies, but as the disease comes on without 

 a preliminary dog-bite, and as the period of incubation is short, and 

 as our first knowledge of it coincides with the appearance of the 

 paralysis when the damage is already done, no practical utihzation 

 can be made of our knowledge of the facts of immunity to the dis- 

 ease at the present time. 



*"Proc. Soc. Exper. Biol, and Med.," igi 2-13, x, i. 



