BLACKWATEK FEVER 97 



The best test to apply is the spectroscopic one, the urine 

 being first diluted with water to render it transparent ; 

 both the haemoglobin and methaemoglobin can be recog- 

 nized at once and with certainty by the use of any of the 

 simplest and cheapest direct vision spectroscopes. The 

 addition of ammonia in cases of methaemoglobinuria 

 will cause the colour to change so that it becomes red, 

 something like the colour of haemoglobin. (Spectra 

 4 and 5, fig. 31). 



The absence or great rarity of blood corpuscles readily 

 distinguishes this disease from any of the forms of haema- 

 turia. Without microscopic examination the transparency 

 of the diluted urine in blackwater fever distinguishes it 

 from the smoky opalescent urine of haematuria cases. 



Prognosis. If suppression of urine is averted the pro- 

 gnosis is good. Constant vomiting and hiccough are of 

 unfavourable import, and great care has to be exercised 

 in order to prevent syncope or cardiac failure. 



Recurrences of the haemoglobinuric attacks sometimes 

 occur at short intervals, sometimes only of a few hours, 

 and in others they follow each other so closely that the 

 urine is never quite clear. Such a relapse may take place 

 within twenty-four hours of a serious attack, or be delayed 

 for three or four days ; it is rare after longer periods, 

 though the interval may be one or two weeks. As each 

 attack runs its own course, a fatal degree of anaemia may 

 be induced, and in each attack there is the same liability 

 to suppression of urine. 



Susceptibility. A person who has once had blackwater 

 fever appears to be specially liable to it, and, if he remains 

 in or returns to a country where the disease exists, will 

 probably have other attacks. These are usually of a 

 similar character to his first attack, so that, if his first 

 attack was a mild one, subsequent attacks will probably 

 be of the same nature. Cases are known of twelve, or 

 even more, such attacks in one person. If, however, the 

 first attack is severe, so will subsequent attacks be, and 

 few persons will survive the third or fourth attack. 

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