696 



SCIENCE 



[N. S. Vol. XXXVI. No. 934 



lower levels. The large peripheral nerves 

 are prevented anatomically from becoming 

 infected in nature, while the small olfac- 

 tory filaments are advantageously placed 

 to act as the means of transportation. 

 Hence the view I desire to place before 

 you, that the nasal mucous membrane is 

 the site both of ingress and egress of the 

 virus of poliomyelitis in man. Support 

 for this view is found also in the study of 

 the microscopic changes in the meninges 

 and the central nervous tissues. Since the 

 virus survives in the dried state it may be 

 carried in dust; and in one instance it has 

 been detected in sweepings from the room 

 occupied by a person ill with poliomye- 

 litis.^^ Its distribution as spray in cough- 

 ing and speaking is readily accomplished, 

 and by this means both active cases and 

 passive carriers may conceivably be pro- 

 duced. Still one link in the chain of 

 causation of poliomyelitis as here outlined 

 remained to be forged. The clinical evi- 

 dence is strong in suggestion that human 

 carriers of the poliomyelitie virus exist. 

 The virus has now been detected in the 

 secretions of the nose, throat and intestine 

 of persons suffering from abortive or am- 

 bulant attacks of poliomyelitis." The un- 

 recognized examples of the abortive disease 

 play a highly important part in the dis- 

 semination of the virus, through which the 

 area of infection is extended, and the num- 

 ber of the attacked increased. A similar 

 part has been accorded by clinical observa- 

 tion to the healthy virus carrier, and the 

 healthy carrier is the last to be detected, 

 and his existence confirmed experimentally. 

 The obstacles in the way of this confirma- 

 tion are considerable but not insuperable. 



'= Neustaedter and Thro, New YorTc Medical 

 Journal, 1911, XCIV., 813. 



^ Kling, Wernstedt, and Pettersson, Zeitschrift 

 fiir Immunitdtsforschung, Originale, 1911-12, 

 XII., 316. 



It is to be remembered that we possess no 

 means of discovering the virus except that 

 of animal inoculation. Should the experi- 

 mental results arising from the inoculation 

 of the secretions of the nose and throat of 

 such healthy carriers be confirmed the evi- 

 dence for the mode of infection as here 

 outlined would be complete. The mem- 

 brane of the nose and throat is far more 

 vulnerable in young individuals, whence 

 arises the greater prevalence during child- 

 hood of those diseases the causes of which 

 seek this avenue of entrance into the body. 

 Among them are included diphtheria, 

 measles, scarlet fever and meningitis. 



Would the establishment of the respira- 

 tory avenue of entrance of the virus ex- 

 clude all other modes of possible infection ? 

 By no means. Plague bacilli are known 

 to be inoculated into man by rat fleas ; but 

 the pneumonic form of the plague is ad- 

 mittedly caused by respiratory inoculation. 

 Diphtheria arises upon the mucous mem- 

 brane of the throat, but can develop in a 

 wound of the skin; the virus of smallpox 

 enters by way of the throat and nose, but 

 can enter by a skin abrasion ; the virus of 

 foot and mouth disease is taken in with 

 food, but produces infection when injected 

 into the skin. Hence at the moment while 

 knowledge is still recent and not yet per- 

 fect the too absolute adherence to one point 

 of view is to be avoided. 



Indeed, the preponderance of cases in 

 the late summer and autumn months early 

 suggested an insect carrier of the infection. 

 House flies can act as passive contamina- 

 tors, since the virus survives upon the body 

 and within the gullet of these insects. It 

 has not proved possible thus far to infect 

 the common varieties of mosquito and the 

 body and head louse, while success has re- 

 sulted in one instance in producing infec- 

 tion in bedbugs which were made to feed 



