THERAPEUTIC IMMUNIZATION IN MAN 495 



INFECTION AND IMMUNITY IN POLIOMYELITIS 



The active experimental investigation of poliomyelitis started 

 with the discovery by Landsteiner and Popper, 102 that monkeys 

 could be inoculated with this disease by the intracerebral or the 

 intraperitoneal injection of saline emulsions of brain or spinal cord 

 of individuals dead of the disease. The same observations by Flex- 

 ner and Lewis 103 a little later, and then by a large number of work- 

 ers throughout the world, gave an opportunity for the careful study 

 of immunological conditions, and of the nature of the virus. It is 

 our own opinion that the disease is caused by the globoid bodies of 

 j^oguchi and Flexner 104 and not by streptococci. However, the work 

 on this controversy may be regarded as unfinished at the present 

 writing, and we may abstain from a prolongued discussion of the 

 etiological factor. The mere fact that the virus of poliomyelitis has 

 been found to keep as long as four to six years in glycerinated ner- 

 vous tissue, and the analogy which this offers to such virus as that 

 of rabies, small-pox, etc., make it alone seem likely that true bac- 

 teria are not concerned in the cause of the disease. Our own ex- 

 periments, and those of Dr. Tsen of this laboratory, on the isolation 

 of streptococci from poliomyelitis animals, incline us to think that 

 animals afflicted with this disease are readily subject to secondary 

 tissue infection with organisms of various kinds, but chiefly with 

 streptococci of the viridans type, which are so universally distributed 

 throughout the body. 



It has long been suspected that one attack of poliomyelitis pro- 

 tected from subsequent infection. It is plain therefore that some 

 form of active immunization takes place in the course of the disease. 

 Experimentation on monkeys subsequently confirmed this, in that it 

 was shown that monkeys that had contracted the disease, and re- 

 covered, were thereafter resistant to inoculation. Strangely enough, 

 however, monkeys that have been unsuccessfully inoculated are just 

 as susceptible as they were before, showing that the immunity in 

 this disease is closely analogous to that existing in syphilis and some 

 other diseases where inoculation with attenuated virus, dead virus, 

 or sub-infectious doses of living virus, is entirely incapable of pro- 

 ducing immunity. 



A brief survey of the epidemiology of the disease will be of value 

 because it throws some light on questions of immunity. An excel- 

 lent and extensive summary of this may be found in the Mono- 

 graph on the disease published by the New York Department of 



102 Landsteiner and Popper. Zeit. f. Immunitats., 11, 1909. 



103 Flexner and Lewis. Journ. Amer. Med. Assn., 1910, liv. 45. 



104 Flexner and Noguchi. Jour. Exp. Med., 1913, XVIII, 461. 



