914 DISEASES CAUSED BY FILTRABLE VIRUS 



ETIOLOGY 



An important advance in the study of this disease was made in 

 1908 when Landsteiner and Popper succeeded in transmitting it to 

 two monkeys ( Cynocephalus hamadryas and Macacus rhesus). The 

 transmission was accomplished by intraperitoneal injections of a saline 

 emulsion of the spinal cord of a child that had died during the fourth 

 day of an attack of infantile paralysis during the stage of acute 

 fever. The first monkey injected became severely ill six days after the 

 injection and died on the eighth day. The second animal became 

 paralyzed seventeen days after the injection and was killed two days 

 later. Cultural experiments with the substance injected were nega- 

 tive, as were also inoculation experiments carried out upon guinea- 

 pigs, rabbits, and mice. The histological lesions produced in the in- 

 oculated monkeys were similar to those occurring in children afflicted 

 with the disease. 



An attempt to transmit the disease to another monkey with spinal- 

 cord substance of the animal that was killed resulted negatively. 



Soon after the successful experiments of Landsteiner and Popper, a 

 similar result was recorded by Knoepfelmacher. 4 An attempt to trans- 

 mit the disease from monkey to monkey was again negative. 



Similar positive inoculation results were published, a little later 

 than this, by Flexner and Lewis 5 in November, 1909, and by Strauss 

 and Huntoon 6 in January, 1910. 



Flexner and Lewis, in their work, moreover, succeeded in trans- 

 mitting the disease through several inoculation- generations of 

 monkeys. The same workers 7 have ascertained that inoculation may 

 be successfully applied not only by the intraperitoneal route but intra- 

 cerebrally, subcutaneously, intravenously, and by the path of the larger 

 nerves. They also proved that not only the brain and cord of afflicted 

 animals contains the virus, but that this may be found, during the 

 early days of the disease at least, in the spinal fluid, the blood, the 

 nasopharyngeal mucosa, and lymph nodes near the site of inoculation. 



Landsteiner and Levaditi, 8 meanwhile, experimenting with the 



4 Knoepfelmacher, Mediz. Klinik, v, 1909. 



8 Flexner and Lewis, Jour. Am. Med. Assn., 53, 1909. 



Strauss and Huntoon, N. Y. Med. Jour., Jan., 1910. 



1 Flexner and Lewis, Jour. Exp. Med., 12, 1909. 



Landsteiner and Levaditi, Comptes rend, de la soc. de biol., Nov., 1909, and 



