540 PATHOGENIC MICROORGANISMS 



develop during an epidemic. Earlier carrier work has lost value 

 to a considerable extent, owing to the fact that the criteria of 

 meningococcus identification of which we are now more thoroughly 

 informed were neglected in these early studies. The flora of the 

 nose and throat contains many Gram-negative diplococci, mentioned 

 above under the heading of identification, some of which were mis- 

 taken in this earlier work for true meningococci. Micrococcus 

 Catarrhalis, Micrococcus Flavus, and a number of other similar 

 microorganisms probably represent a definite percentage of the 

 earlier statistics. The criteria of meningococcus determination have 

 been discussed in a special section above, and these, in general, were 

 applied in the extensive meningococcus carrier work which was done 

 during the years of the war, especially by British and American 

 bacteriologists. The studies of Bassett-Smith, 48 Gordon, 49 Mathers 

 and Herrold, 50 show that in the American camps under conditions 

 of ordinary life and weather, there may be anywhere from two to 

 five per cent of meningococcus carriers. Mathers and Herrold at 

 the Great Lakes Naval Training Station examined over 15,000 men, 

 finding over 4 per cent to be carriers and between 1 and 2 per cent 

 to be chronic carriers. Their work also showed that the carrier 

 rate is higher among those taking care of cases, and that over 

 38 per cent of those recovering from the disease may remain carriers 

 during convalescence for variable periods. Contacts showed a 

 carrier rate of 36.7 per cent during a period in which the general 

 carrier rate in the camps (15,000 men examined) was slightly over 

 4 per cent. The hospital Corps showed a carrier rate of 13.5 per 

 cent. It is natural that there have been many endeavors to establish 

 relationship between new cases and contact with carriers. This line 

 of investigation has not been conclusive, owing to the great difficul- 

 ties incident to such investigation. The transmission of respiratory 

 organisms may take place during a very brief contact, in conversa- 

 tion, close association in barracks, moving picture shows, public 

 conveyances, sleeping quarters, etc., and the innumerable associa- 

 tions of this kind established by each man in the course of a day, 

 makes it almost impossible to trace them with accuracy. Among 

 the most interesting studies made in this connection are those of 



48 Bassett-Smith, Lancet, 194, 1918, 290. 



"Gordon, Med. Res. Com., Spec. Rep. Ser., No. 3, London, 1917. 



50 Mathers and Herrold, Jour. Infect. Dis., 22, 1918, 523. 



