614 



SCIENCE 



[N. S. Vol. XLIV. No. 1139 



ON THE ETIOLOGY OF EPIDEMIC 

 POLIOMYELITIS 1 



By the combined use of methods employed 

 by Eosenow in a bacteriologic study of vari- 

 ous diseases including diseases of the nervous 

 system and the methods of Flexner and 

 jSToguchi in their study of poliomyelitis, we 

 have isolated from all of 52 cases of polio- 

 myelitis a peculiar streptococcus. This organ- 

 ism has been obtained from the throats, ton- 

 sils, abscesses in tonsils and from the central 

 nervous system. It has been obtained from 

 the ventricular fluid after death, but not from 

 the spinal fluid during life. In only one in- 

 stance has it been isolated from the blood 

 during life. 



In seventeen fatal eases the tonsils showed 

 from one to fifteen abscesses. These were 

 situated near the capsule and contained a 

 peculiar gelatinous opalescent material from 

 which this peculiar streptococcus was isolated 

 in large numbers. 



The microorganism is remarkably poly- 

 morphous, appearing to grow large or small 

 according to the medium on which it is grown. 

 Details as to its growth on various media may 

 be found in the Journal of the American Med- 

 ical Association for October 21, 1916. In gen- 

 eral, it may be said that under aerobic culti- 

 vation and in dextrose-containing media, the 

 organism tends to grow large, while in ascites 

 fluid in tall tubes containing tissue, the small 

 forms predominate. The latter appear to be 

 identical with the microorganism described 

 and cultivated by Flexner and !N"oguchi. 



Cultures of Berkfeld 1ST filtrates of emulsions 

 of brain and cord of rabbits which died of 

 paralysis after intravenous injections of sus- 

 pensions of broth cultures showing only the 

 large forms have repeatedly grown out in 

 suitable media. The microorganism has been 

 grown also from the filtrates of cultures show- 

 ing the small form but not from filtrates of 

 cultures showing only the large form. It has 



i From the laboratories of the Mayo Founda- 

 tion and the New York Hospital. Presented he- 

 fore the Minnesota State Medical Association, 

 Minneapolis, October 13, 1916. 



been isolated from the brain and cord of par- 

 alyzed monkeys following intracerebral injec- 

 tion of fresh human virus and glycerinated 

 human and monkey virus. 



The large form of the organism, injected 

 intravenously or intracerebrally, has produced 

 paralysis consistently in animals (rabbits, 

 guinea-pigs, dogs, cats) which are known to 

 be quite insusceptible to inoculations by the 

 methods which infect monkeys — injection of 

 emulsions of brain and cord from patients 

 with poliomyelitis. After producing paralysis 

 consecutively in three rabbits one strain caused 

 characteristic paralysis and lesions of polio- 

 myelitis in monkeys. 



The cords of paralyzed animals have shown 

 lesions very similar to those of experimental 

 poliomyelitis in monkeys : hemorrhages and 

 round-cell infiltration in the gray matter, as 

 well as degeneration of the ganglion cells and 

 neurophagocytosis. 



Lesions, other than those in the central 

 nervous system, were relatively few, but when 

 present were most commonly found in lymph 

 glands, the spleen, lymphoid structures in the 

 intestinal tract, particularly in the colon and 

 in the splanchnic region. Pure cultures of 

 the organism have been obtained from the 

 central nervous system in numerous animals 

 when blood and other tissues were sterile. 



It appears that the small filterable organism 

 of Flexner and Noguchi which has been gen- 

 erally accepted as the cause of poliomyelitis 

 is probably the form which this streptococcus 

 takes in the central nervous system and in 

 suitable culture media under anaerobic condi- 

 tions, while the larger, more virulent and more 

 typically streptococcic form which other inves- 

 tigators have considered contaminations is the 

 same organism grown larger on suitable media. 

 The larger forms may play an important part 

 in the epidemiology of poliomyelitis. 



E. C. Eosenow, 

 The Mayo Foundation, Rochester, Minn., 



E. B. Towne, 

 Peter Bent Brigham Hospital, Boston, Mass., 



G. W. Wheeler 

 New York Hospital, New York 



