490 PATHOGENIC MICROORGANISMS 



The pandemic of 1889 probably started in the East where it is 

 quite likely that an outbreak of so-called "dengue fever" in Con- 

 stantinople in 1888 formed one of the earliest manifestations. Late 

 in 1888 and in early 1889, it seems to have appeared synch ronously 

 in Greenland, in Russia and in Siberia. Ileyfeldcr 13 saw cases in 

 Bokhara in May, 1889, and wrote of its enormous westward speed 

 of travel. In October it reached Petrograd, and in November 

 entered Germany. It swept westward through France, Austria and 

 Italy, reaching Spain in early December, New York and London by 

 the middle of December, and by this time had also reached the 

 United States from the other side, having traveled eastward as well 

 as westward from its origin. 



It is quite certain at the present time that influenza is spread by 

 direct and indirect contact. The tempestuous suddenness with 

 which it attacked whole communities formerly gave rise to the 

 opinion that it was spread by other means, such as air, dust, etc., 

 but studies of the last two epidemics seem to contradict this. It 

 does not travel more rapidly than human communication, as shown 

 during the 1889 epidemic by Parsons, 14 Friedrich, 15 and others. 

 Communities that are out of touch with infected populations by 

 reason of lack of communication (islands, mountain tops, etc.), 

 usually remain uninfected. Examples of this were noted during 

 the 1889 epidemic on the Island of Borkum, and on the Senlis 

 mountain. In large cities the epidemics burn themselves out within 

 a relatively short time, while in country communities where com- 

 munication is slower and the population is scattered, it travels more 

 slowly and lasts longer. According to the studies of Abbott of the 

 epidemic in Massachusetts in January, 1890, it was shown that from 

 the 4th of January to the 10th of February, there were about 

 800,000 cases, that is, about 40 per cent of the population, and the 

 disease had practically burnt itself out in this short period. In 

 London, the epidemic appeared in December, attained a death rate 

 of 28.1 per thousand, during February, and began to decline in 

 March. During the last pandemic similar facts were observed, al- 

 though the state of war, necessitating the transportation of large 

 bodies of men from one part of the world to another, rendered 

 tracing of the correlationship of influenza and travel routes extremely 



" Hey i 'elder, Wien. klin. Woch., 1890, 3, 11. 



** Parsons, Local Government Board Eeport, London, 1893. 



25 Friedrich, Arb. a. d. k. Gesundh., 1894, Bd. 9. 



