484 
C. A. MAC MUNN. 
It is not a difficult matter to obtain solutions of this colour- 
ing matter for spectroscopic examination, as it is taken up by 
a great number of solvents, in which point it differs much 
from the blood pigment of most invertebrate animals; and it 
resembles in its solubility lutein and tetronerythrin (= Kru- 
kenberg’s lipocliromes) ; still its spectroscopic and other cha- 
racters show that it is not either one or the other. 
Echinochrome can be obtained in solution and isolated by 
two methods : (1) The fresh blood-clot can be extracted with 
the solvents mentioned below, or (2) the clot may be separated 
from the serum by filtering, the pigment dried at the tempera- 
ture of the air (as it changes by using heat) and the dried 
pigment thus obtained treated by solvents. By the adoption 
of the latter method it can be obtained in a purer condition. 1 
The “ serum ” after separation of the clot is a faint yellow 
colour and shows two faint bands in green, but if allowed to 
stand some time in contact with the clot it becomes a faint violet 
red, and then shows Chart II, sp. 2. Treated with caustic 
soda these bands are intensified, but then the fluid is not quite 
as coloured as before, but if instead stannous chloride be added 
the dark bands of sp. 3, Chart II, appear, the fluid being then 
violet-reddish. These bands read from X 54T5 to X 532 and 
X 506 to 486'5 ; on agitation with air they are not as distinct 
but do not altogether disappear. 2 The serum was found to be 
faintly acid, or neutral, faintly opalescent on heating, opales- 
cent with absolute alcohol, and faintly so with ether. 
The brownish-red clot shows after standing in contact with 
the “ serum ” sp. 4, Chart II, and with caustic soda sp. 
5, II. 
An absolute alcohol solution of the fresh clot is a 
red colour, allowing red, orange, yellow, and a little green to 
pass in a deep layer, while in a thinner layer examined by day- 
light sp. 6, Chart II is seen. These bands have the following 
1 The filter paper with the dried pigment on it is cut up and put into test- 
tubes containing the solvents, and corked up and left in a dark place. 
2 Because in the oxidised condition bands of the same kind, but feebler, 
are visible. 
