PHOSPHORUS. 
§ 304-] 
247 
wide, but may be invisible if the slit is too narrow. It is best seen by 
M. Salet’s second process, and, when cooled by a brisk current of air, it 
broadens, and may extend closer to D. The band y has a somewhat 
decided border towards E, while it is nebulous towards D, and it is, 
therefore, very difficult to say where it begins or where it ends ; its 
centre may, however, be put at very near 109 of Boisbaudran’s scale, 
corresponding to W.L. 560*5, if the flame is free. This band is more 
distinct than jS, but with a strong current of air the reverse is the case. 
The middle of the important band a is nearly marked by Fraunhofer’s 
line E. Boisbaudran gives it as coinciding with 122 of his scale, W.L. 
526*3. In ordinary conditions (that is, with a free uncooled flame) this 
is the brightest and most marked of all the bands. The approximate 
middle of the band j8 is W.L. 510*6 (Boisbaudran’s scale 129*00). 
Lipowitz’S Sulphur Test. —Sulphur has the peculiar property of con¬ 
densing phosphorus on its surface, and of this Lipowitz proposed to take 
advantage. Pieces of sulphur are digested some time with the liquid under 
research, subsequently removed, and slightly dried. When examined in 
the dark, should phosphorus be present, they gleam strongly if rubbed with 
the finger, and develop a phosphorus odour. The test is wanting in delicacy, 
nor can it well be made quantitative ; it has, however, an advantage in 
certain cases, e.g. the detection of phosphorus in an alcoholic liquid. 
Scherer’s test, as modified by Hager, 1 is a very delicate and almost 
decisive test. The substances to be examined are placed in a flask with 
a little lead acetate (to prevent the possibility of any hydric sulphide 
being evolved), some ether added, and a strip of filter-paper soaked in a 
solution of silver nitrate is then suspended in the flask ; this is con¬ 
veniently done by making a slit in the bottom of the cork, and in the 
slit securing the paper. The closed flask is placed in the dark, and if 
phosphorus is present, in a few minutes there is a black stain. It may 
be objected that arsine will cause a similar staining, but then arsine 
could hardly be developed under the circumstances given. It is scarcely 
necessary to observe that the paper must be wet. 
§ 304. Chemical Examination of the Urine. —It may be desirable, 
in any case of suspected phosphorus poisoning, to examine the renal 
secretion for leucin and tyrosin, etc. Leucin may be found as a deposit 
in the urine. Its general appearance is that of little oval or round discs, 
looking like drops of fat. It can be recognised by taking up one or more 
of these little bodies and placing them in the author’s subliming cell (see 
p. 261). By Careful heating it will sublime wholly on to the upper cover. 
On now adding a little nitric acid to the sublimed leucin, and drying, 
and then to the dried residue adding a droplet of a solution of sodium 
hydrate, leucin forms an oily drop. Tyrosin also may occur as a sediment 
of little heaps of fine needles. The best test for tyrosin is to dissolve in 
1 Pharm. Central-halle, xx. 353. 
