YELLOW FEVER EXPEDITION 
523 
volumes have been added ; three volumes give increase of the precipitate. The 
clear filtrate from this still gave slight haze with more absolute alcohol. This pre- 
cipitate was collected and found readily soluble in water ; the solution gave 
xanthoproteic reaction with nitric acid and ammonia strongly, and with weak copper 
sulphate and caustic soda a pink biuret reaction was obtained. 
F, E, fatal yellow fever ; three days before death. Urine loaded with albumen ; 
in this case no acetic was added before boiling, otherwise similar procedure, the pre- 
cipitate resulting from large addition of absolute alcohol (tour volumes) was collected 
with the centrifuge and dissolved in a small quantity of rainwater. Clear yellowish 
solution, frothing on shaking, obtained. This, like the original filtrate, gives no 
reaction with boiling, with or without acetic or with nitric acid. With picric acid, 
and with acidified corrosive sublimate precipitation occurs ; also concentrated amnionic 
sulphate and saturated sodium sulphate, when acidified with acetic acid, both give a 
good ring. It also yields a strong xanthoproteic and beautiful pink biuret reaction. 
In other cases saturation with amnionic sulphate was tried in order to precipitate 
the presumed albumose, after boiling with acetic acid and filtering. In order to 
avoid the urates the crystals of the salt were generally added, gradually, with inter- 
vening filtrations ; on testing the filtrates with nitric acid and ammonia, an orange 
xanthoproteic reaction could be obtained until the point of complete saturation. 
Owing to the pigmented urates, and often biliary pigments, much difficulty was 
experienced ; still in some cases the resulting final precipitates when dissolved in 
water, besides giving a good colour with nitric acid and ammonia, sometimes gave a 
pink colour with the biuret reaction. Picric acid also gave precipitates, per- 
manent on heating ; whilst boiling, with or without acidification, nitric acid and 
potassium ferrocyanide and acetic all failed to give signs. A number of attempts, 
such as the use of saturated amnionic sulphate, were tried for clinical purposes, but 
the large amount of urate present, especially in acute cases, shewed that these means 
were valueless. 
In conclusion, it may be said that a more soluble form of proteid appears to be 
present in the urine in yellow fever. This is precipitable by higher grades of alcohol 
after the removal of the less soluble proteids, if present, and is also thrown down by 
amnionic sulphate in saturation. Unless it is some alteration product of the more 
precipitable proteids, it appears to belong to the proteose class ; it remains in the 
urine after the more precipitable proteids have ceased to be passed, and also occurs 
in slight cases in which there is never any or only slight traces of these bodies. The 
use of picric acid and heat seems the best mode of showing its presence tor clinical 
purposes. How far it can be used for the differential diagnosis of yellow from other 
fevers must be left to the future. 
When the urine contains large quantities of albumin, the simple addition of 
acetic acid or a few crystals of neutral salt as sodium sulphate will bring down much 
