246 DR. C. A. MAC MUNN OX ENTEROCHLOROPHYLL, AHD ALLIED PIGMENTS. 
spectra to the chromophans individually, and which Krukenberg has assumed to be 
identical with the chromophans, failed to give any blue coloration with iodine in 
iodide of potassium, and their reactions with sulphuric and with nitric acid were 
equally unsatisfactory. 
Krukenberg, * taking Kuhne’s researches as a basis, has proposed that all those 
animal pigments which are soluble in certain solvents, which give bands in the blue 
and violet parts of the spectrum, and the above reactions when in the solid state, 
should be included under one name, that of the lipochromes. He has found these 
lipochromes widely distributed through the animal kingdom. In his early publi¬ 
cations he restricted the term to the luteins, but he now includes zoonerythrin 
(= tetronerythrin). But it seems to me that this generalisation is too great, and 
that the abandonment of the old term lutein is likely to lead to confusion. However 
Krukenberg deserves great credit for having evolved order out of chaos, and 
whether we accept the name lipochromes or not, will matter little if it be kept in mind 
that they are mostly all lutein-like pigments. 
In most cases Krukenberg applied Kuhne’s saponification method to the isolation 
of the lipochromes, and found that they “ withstand ” heating with caustic soda; but I 
cannot altogether agree with this, because in some cases bands previously invisible 
come into view, and in many cases bands are much intensified, showing a decided 
change in the composition of the pigment. 
Dr. Adolph Hansen t applied the same method to the chlorophyll of young wheat 
plants, and was led to some important conclusions as to the composition of chlorophyll; 
lie says he has restored to Kraus | the right of having been the first to show how to 
separate chlorophyll into its constituents. 
I need not describe the preliminary treatment to which he subjected his plant- 
material, but limit myself to the description of the saponification. 
The alcohol extract of the leaves is concentrated by evaporation, and the 
concentrated extract treated when boiling drop by drop with caustic soda solution; 
when the alcohol has evaporated water is added, and the solution heated again. 
After the evaporation of the greater part of the water alcohol is again added and 
the saponification ended. When the alcohol has gone chloride of sodium is added in 
excess to ensure the separation of the soap. The green soap is now extracted in the 
separating funnel with petroleum-ether, the extraction being repeated as long as the 
petroleum-ether appears yellow. The soap is then shaken with pure ether, after 
which it is extracted with ether containing“ some cubic centimetres” of alcohol which 
extracts the green constituent. In this way the two colouring matters composing 
* ‘ Vergleickend-pbysiologiscbe Studien,’ 1880-1882, and ‘ Grundziige einer vergleiekenden Physiol- 
ogie der Farbstoffe und der Farben,’ 1884; also ‘ Grundriss der med.-ckem. Analyse,’ 1884. 
t ‘ Arbeiten des botanisclien Instituts zu Wurzburg,’ Bd. 3, Heft i., and ‘ Verhandlungen der phy- 
sikalisch-mediziniscken Gesellsckaft zu Wurzburg,’ N. F., Band 18, (1884), p. (109). See “Nature,” 
vol, 30, p. 224. 
X ‘ Zur Kenntniss der Ckloropbyllfarbstoffe und ihrer Venvandten,’ Stuttgart, 1872. 
