58 
SINAPINE TISSUE. 
By comparing, then, the effect upon the liquor of a sample of spirit of nitre, 
with that of a standard solution of nitrous ether, the strength of the former may 
be readily ascertained. 
The standard employed in my experiments was composed of 5 volumes of 
nitrous ether prepared by Liebig’s process, and 95 volumes of rectified spirit. 
Instead of this, the impure ether made by the Dublin process may be used. 
When carefully prepared, it contains, according to my trials, about 65 per cent, 
by volume of nitrous ether. The solution should be neutralized with acetic 
acid, if reddened litmus paper turn blue when dropped into it. 
The experiments may be performed as follows:— 
Take two one-ounce stoppered bottles of colourless glass, and introduce into 
each half a fluid ounce of the test liquor. To one portion add the sample of 
spirit of nitre by a few minims at a time, and at intervals of a minute or so, 
until the mixture appears of a bluish-green colour ; then close the bottle, and 
note the quantity of spirit which has been expended. A small Mohr’s burette, 
graduated in minims, is very useful for this work. Now add cautiously the 
standard solution to the other portion of the test-liquor until it shows exactly 
the same tint as the last. From the quantity of the standard and of the sample 
used, the strength of the latter may be easily calculated. 
The precautions to be observed are—1. If the sample turn solution of iodide 
of potassium brown, it should be shaken with a little magnesia and filtered. If 
this be not done, the result will be too high. 2. If the sample and standard 
differ much in strength—if, for instance, the latter be ten or twelve times as 
strong as the former—the result will be rather too low. This small error may 
be avoided by properly diluting the stronger solution with rectified spirit. 
3. The standard solution should be fresh, or at all events not more than a few 
days old. 
The following are among the results obtained :— 
In spirit of nitre made according to the British Phurmacopceia, except that 
the nitrite of soda was dissolved in twice its weight of water, between 6 and 7 
per cent, of nitrous ether was found. It amounted to about 10 per cent, of the 
first fifth of the distillate, Avhich was of pleasant odour and flavour, and nearly 
free from aldehyde. The next two-fifths were almost pure spirit of wine. The 
last two-fifths contained the remainder of the ether and much aldehyde. A 
spirit of about the same strength as the above, but much more fragrant and 
palatable, and quite free from aldehyde, may be made by using a nitrite of 
soda containing 40 per cent, of real nitrite, and decomposing this by so small 
an excess of sulphuric acid as to leave the nitrate of soda intact. In carefully- 
prepared P.L. spirit of nitre only about 1 per cent, of nitrous ether could be 
discovered. 
An examination of ten samples of the best spirit of nitre—fair specimens, pro¬ 
bably, of the article in general use—showed the average content of nitrous 
ether to be 0'8 per cent. The highest result was 1-26, and the lowest O'o per 
cent. 
I may observe, in conclusion, that by a similar process to the above, the esti¬ 
mation of nitrite of soda can be effected with considerable accuracy. 
Sheffield, July, 1866. 
SINAPINE TISSUE. 
TO THE EDITOR OF THE PHARMACEUTICAL JOURNAL. 
Sir,—My attention has been recently directed to an article purporting to be 
an elegant and efficient substitute for the ordinary mustard poultice. It is 
called “ Sinapine Tissue,” or “Mustard Paper,” and is put up in an envelope 
