.25 



on record some fairly convincing instances of a second more or less 

 grave attack a year or longer after the first. 



DIAGNOSIS. 



The increase in knowledge concerning the etiology of various com- 

 municable diseases and the improvement in methods devised for their 

 recognition have been followed, among other things, by a broaden- 

 ing of our conceptions relating to the degrees of severity which they 

 may assume. Thus when, for example, we speak of typhoid or 

 cholera we think not only of the severe classical types, but we have 

 in mind also those mild and irregular forms which are recognizable 

 only because of the improved tests which are at our command. 



We now know that, like cholera and typhoid, yellow fever also mani- 

 fests itself in all grades of severity; but unfortunately, unlike the 

 former, we have no test whereby in any particular case we can say 

 definitely that this is or is not yellow fever. The recognition of this 

 fact is of the very highest importance with respect to prevention, for 

 it makes it imperative that in infectible regions every case of fever, 

 however mild, should be considered as potentially yellow fever until 

 this disease can positively be excluded. 



On taking charge of a case of fever the practitioner, in the South, 

 should therefore start with the assumption that he is dealing with a 

 case of yellow fever, and in formulating his final, definite diagnosis, 

 in which this disease is excluded, he must use the greatest care and 

 caution. The clinician must fix it firmly in his mind that yellow fever 

 is not excluded simply because he knows of no other previous case; 

 obviously he may be dealing with the first case himself, or several 

 cases may have occurred in such as, for one reason or another, had 

 received no medical attention. Nor is yellow fever eliminated from 

 consideration because he fails to detect any so-called "characteristic" 

 sign or symptom. 



Ordinarily the combination of an acute fever with albuminuria, jaun- 

 dice, an irresponsive or divergent pulse, a tendency to hemorrhage from 

 the mouth, and gastric irritability, with no material alteration in the 

 size of the liver and spleen, should leave no doubt in the observer's 

 mind as to the nature of the disease with which he is dealing. 



The diseases with which yellow fever may be confused are malaria, 

 hemoglobinuric fever, dengue, grippe, bubonic plague, typhoid fever, 

 acute yellow atrophy of the liver, Weil's disease, and relapsing fever. 



Malaria. — Yellow fever at times simulates certain irregular forms 

 of malaria very closely, and in the absence of any known infection the 

 grave error of mistaking it for malaria has, not rarely, been com- 

 mitted. On the other hand, during epidemic seasons the mistake is 

 not infrequently made, both within and without the infected zone, of 

 calling malaria yellow fever. 



