488 
C. A. MAC MUNN. 
feeble shading extending to A 484‘5, and with stannous chloride 
the result was the same as before. 
A benzene solution of the dried clot gives sp. 16, II, and 
is similarly changed by stannous chloride ; the bands produced 
by this reagent: — measuring first from A 538'5 to A 516, the 
second A 505 to A 484'5. 
A petroleum ether solution gave a similar spectrum, and 
altered in the same manner by stannous chloride. 
Glycerine is also a good solvent for fresh echinochrome, 
it forms with it a deep red solution in which two bands are 
seen, the first from A 560 to A 545’5, sp. 17, II. On treatment 
with caustic soda the solution is reddish-yellow, and two bands 
(as in other cases) are seen ; the first from A 54T5 to A 516, 
and the second A 503 to 484'5 (?). On adding acetic acid to 
this solution they disappear, and they can be brought back with 
more caustic soda. When a glycerine solution is treated with 
acetic acid, the same change as that produced by this reagent 
in the case of alcohol solutions takes place (see Chart II, sp. 7). 
Hydrochloric, sulphuric, and nitric acid produce the same 
effect. Ammonia changes the red colour to orange yellow, 
and this solution shows two bands : first, A 537 to A 516 ; 
second, A 501 to A 482'5. On treating a glycerine solution 
with stannous chloride the solution is reddish yellow and gives 
sp. 18, II ; the first band is from A 540 to A 513, the second 
from A 503 to A 481 ; they are unaffected by hydrochloric acid. 
The above are the most important characters of echinochrome; 
the colours of the solutions were observed mostly by gaslight 
owing to circumstances over which I had no control. 
Although I have now examined a great number of animal 
colouring matters, I have not met any which — as regards 
spectra and solubility — resembles this one. 
It is partially soluble in water and alcohol, soluble in gly- 
cerine, ether, chloroform, benzene, bisulphide of carbon, and 
petroleum ether. It is certainly capable of existing in two 
states of oxidation, 1 and is therefore respiratory. It is — when 
1 The surmise of Krukenberg that the appearance of the dark bands on 
