106 BOTANICAL MICROTECHNIQUE. 



The absorption-spectrum of the aqueous solution has, ac- 

 cording to Schiitt, a certain similarity to the chlorophyll 

 spectrum, in that it shows Band I. 



b. Fatty Pigments or Lipochromes. 



180. At present, all those yellow or red pigments which 

 are colored blue by sulphuric or nitric acid, and green by 

 solutions of iodine with potassium iodide, are called fatty 

 pigments or lipochromes. They are mostly dissolved in 

 fatty substances within the living cell. 



Zopf (IV) has recently investigated the relations of the 

 lipochromes, especially toward sulphuric acid, and has 

 proved that, in this reaction, deep-blue crystals often occur, 

 which he calls lipocyanin crystals. These are formed espe- 

 cially when rather dilute sulphuric acid is added to the 

 residue from an evaporated solution of a lipochrome upon 

 the slide. Zopf also succeeded in obtaining lipocyanin 

 crystals directly from various organs by letting the sections 

 dry before treating them with sulphuric acid. 



181. According to their chemical relations, the already 

 described pigments, carotin and xanthin, belong to the lipo- 

 chromes (cf. 170 and 173). There also belongs here the 

 red pigment prepared by Cohn from the cells of Hcemato- 

 coccus, which he calls hcematochrome. The pigment called 

 chlororufin by Rostafinski (I) is also to be included here. 

 Zopf and Bachmann have prepared various lipochromes 

 from different fungi (cf. Zopf II, 414). Finally, the bacteria- 

 purpurin prepared by Lankaster from various red Bacteria 

 is to be placed among the lipochromes, according to Bu't- 

 schli (I, 9), whose studies indicate that it is identical with 

 Cohn's haematochrome. 



Whether all these pigments are nearly related chemically, 

 and how far they are identical with each other, or, on the 

 contrary, consist of groups of more or less different pig- 

 ments, must be determined by further investigations. 



