622 
DR. A. GAMGEE ON THE ACTION OE NITRITES ON BLOOD. 
When a layer of these crystals is examined with the micro-spectroscope of Mr. Sorby, or 
with an ordinary spectroscope, the spectrum of nitrite-blood is seen to perfection. 
The chocolate-coloured deposit may be dissolved in water, with the aid of a little heat, 
and the solution having been filtered may be treated with alcohol and frozen, when 
crystals identical in shape, colour, and optical properties with those precipitated the first 
time will again separate. The crystals when agitated with water give to it a dirty-brown 
colour ; sometimes I have obtained them of such a size that, when shaken with water, 
they could be seen to float about as minute needles. If to this dirty-brown fluid a drop 
of ammonia be added the change is most marked and beautiful ; for the fluid assumes 
the magnificent red colour of haemoglobin. 
If the crystals are drained by being placed on filtering paper laid on porous slabs, 
and then dried as rapidly as possible in vacuo over sulphuric acid, a reddish-brown mass 
is obtained which readily crumbles to powder. The crystalline form of the substance is 
lost in the process of drying. The dry body, when powdered, is soluble in pure water 
at the temperature of the body ; it is much more readily soluble in water containing a 
trace of free ammonia ; in this case a red, instead of a brown solution is obtained. 
When the dry body is ignited an ash is left which has an alkaline reaction, and which 
contains only oxide of iron and potash. 
3*379 grammes of the nitrite-of-potassium compound of haemoglobin yielded on igni- 
tion a red ash, which was treated with water and evaporated, and then after the addition 
of hydrochloric acid ignited. 
The chloride of potassium obtained weighed 0-014 grm. 
100 grammes would therefore yield 0-47 of KC1. 
5'2 grammes of the nitrite-of-potassium compound prepared at a different time yielded 
0-026 grm. of KC1. 
100 grammes would therefore yield 0‘57 grm. of KC1. 
The amount of potassium in the nitrite compound was by these analyses shown to be 
so small as to render very accurate results scarcely attainable. The results agree very 
nearly with the view that a molecule of haemoglobin combines with a molecule of nitrite 
of potassium. 
2. Action of Nitrite of Sodium on Haemoglobin. 
If a solution of nitrite of sodium be substituted for a solution of nitrite of potassium, 
the changes which have been described under 1 all occur, and crystals are obtained which 
only differ from the first by containing Na instead of K. 
3. Action of Nitrite of Silver on Haemoglobin. 
When a solution of haemoglobin is treated with a solution of freshly prepared and 
several times recrystallized nitrite of silver, it immediately becomes chocolate-coloured, 
and presents the spectrum of blood treated with nitrites. The solution reacts exactly 
as solutions of Hb which have been treated with the alkaline nitrites when ammonia 
