﻿96 ASHBURN AND CRAIG. 



They also speak of some experiments they made on mosquito transmission, 

 but they do not publish the work, and state that they attach little value to it. 



Cazamain ( 8 ) , in reporting an epidemic on the French ship Kersaint, suggests 

 the possibility of the mosquito acting as a "carrier." 



The Australian committee (Robertson) report (9) says: "It is undoubtedly 

 highly infectious, but clinical observation does not enable us to form any definite 

 opinion as to the mode in which the infection is carried from person to person. In 

 some respects the spread of the disease suggests some peculiarity in the method of 

 propagation differing from that of the well-known diseases, influenza, scarlet 

 fever, measles, etc. It appeared to spread particularly to contiguous houses, 

 whole streets being attacked seriatim. One observation appears to have some' 

 bearing on the method of propagation. That is, the medical men have, in many 

 instances, appeared immune to the disease, although exposed to it daily, indeed 

 hourly, until cases appeared in their own households, when they fell victims, 

 being usually among the last members of the households to be attacked." 



Hirsch (10) says that its infectiousness is certain, its contagiousness doubtful, 

 but he gives some significant quotations that suggest mosquito transmission. Thus 

 he quotes Waring (North Amer. M. & S. Jour., 1830) as saying of the epidemic 

 of 1826, "the breakbone fever has been suppressed by the frost," and of that 

 of 1828, "it terminates under the effect of frost." Arnold (11) he quotes as 

 follows: "This disease is undoubtedly affected by frost. The diminution of cases 

 last fall was as marked as the diminution in our endemic climate [yellow] fever 

 usually is." 



Speaking of the Madras epidemic of 1872 Hirsch says that it ended in the 

 middle of October with the onset of strong winds and colder weather. He also 

 cites instances to show that freedom from epidemics is conferred by altitude. 



Leichtenstern (12), although regarding the disease as contagious, makes the 

 following suggestive observations concerning it: 



1. It is a disease of tropical and subtropical zones, and in these zones it has 

 a marked preference for the hot season, and almost always ends, as if suddenly 

 cut off, on the recurrence of cold weather or the beginning of the cool season. 



2. It is a disease of sea coasts and ports, and coast cities, and may go up large 

 navigable streams, as the Mississippi. It rarely occurs inland or at high altitudes. 

 When it went 4,000 feet high on Lebanon in 1889 the season was exceptionally 

 hot. 



3. He considers it a "highly contagious" disease, carried by ships, pilgrims 

 and emigrants; nevertheless, contagion alone, in the strict sense of the term, 

 can not satisfactorily explain its occurrence and spread. 



4. He calls it contagious-miasmatic; that is, it is contagious from person to 

 person, but only under certain conditions of time and place. 



5. He likens its manner of spread (he wrote prior to the work of Reed, Carroll, 

 et al.) to that of yellow fever. 



Sandwith (13), writing of the disease in Egypt, says it always begins in 

 August and September, with the rains, and ends in December, when colder weather 

 begins. In speaking of its relation to surface water he says: "The conclusion 

 would seem to be that dengue, with its unexplained affection for coasts, rainy 

 seasons and large rivers, only appears in Egypt when the Nile is in its annual 

 flood." He believed the disease to be contagious but cites instances that appear 

 to point to some other method of diffusion. 



Smart (14) likened the disease in some ways to yellow fever but said: "There 

 is sufficient evidence of its infectious, if not of its contagious properties." 



Eayrer (15) says: "The degree of eommunicability as well as the work of 

 communication can, however, hardly be regarded as a settled question." He 

 quotes Charles as expressing "his belief that wben the eruption is out the danger 



