CONTRIBUTIONS TO ANIMAL CHROMATOLOGY. 93 
and so on, yet these tests had been forgotten, or rarely used 
until Kiihne directed renewed attention to them. 
The lipochromes, collectively, are soluble in those solvents 
which dissolve fat, such as chloroform, bisulphide of carbon, 
ether, alcohol, turpentine, &. They give one or two bands, 
or rarely three, in the blue half of the spectrum ; they are 
sensitive to light when in solution; they are said to contain 
only carbon, oxygen, and hydrogen, no nitrogen; they vary in 
colour, being green-yellow, yellow, orange, or red. Their 
absorption bands are hazy and indistinct, which is owing to 
their occurrence in the more refrangible part of the spectrum. 
I find, however, that when examined in a diffraction spectroscope 
the bands are much sharper and narrower. Their “ bleach pro- 
ducts,” according to Krukenberg, are similar to cholesterin, and, 
finally, in the solid state they are coloured blue, blue green or 
greenish, by nitric, and also by sulphuric, acid. I find, as I 
have often stated elsewhere, that the animal lipochromes rarely 
respond to the iodine test, whereas the plant lipochromes often 
become blue or blue green. Most, if not all, according to 
Krukenberg, withstand boiling with caustic alkalies. I am not 
so sure that this statement is true however. This observer re- 
marks that a sharp delimitation of these pigments is impossible, 
since they go over into the lipochromoids and the melanoids, and 
Kine has found that a real lipochrome, viz.—rhodophan, after 
sufficient purification, shows no blue colouration with nitric 
acid (doubtless in this case purification = decomposition). 
Krukenberg takes carrotin as the type of a lipochrome, and 
attributes to it the formula C,,H.,,0; he says this crystalline 
colouring matter shows direct relationship to hydrocarrotin, to 
which he assigns the formula C,,H;,O ; but these figures, which 
are Husemann’s,! have recently been shown to be erroneous. 
Thus Arnaud? has shown that carrotin is identical with the 
orange-red crystalline substance which can be obtained from 
green leaves, and which also exists in many fruits, especially 
the tomato. He finds that it has the composition C,,H,,, and 
1 © Ann, d. Chem. u. Pharm.,’ Bd. 117, 8. 200. 
2 Arnaud, ‘ Compt. rend.,’ C. ii, 1119—1122 ; also 1819—1322. 
