CAROTINOIDS IN Till- CRYPTOGAMS 105 



Order Protococcalcs (lowest forms, unicellular) 



Sphacrclla (Haematococcus <>r Chlamydococcus) pluvialis Culm. 1850, 



Koftulinski. 1881; Kli-l-s. INS:',; Zopf, 1895; Knhl. I'.ttrJ; Jacobsen, 



1913; van \Vi-.'lmi:li, 1915. 

 Volro* Cohn. 1867. 



Protocofcu* (Plewococcus) pluvialis Cohn, 1S50, IsdT. 

 Pruttin;-u* ntlyaria \an Wisselingh, 1915. 

 Scotiiwsphacra paradoxa KK-hs, 1881. 

 1'ltt/lluhium ilinn>ii>iinin. P. incertumsKlebs, ls*l. 

 Hydrodictyon utnculuimn (water-net) Tammes, 1900. 



In Zopf's (1892a) first study of hacmatochrome it was pointed out 

 that the previous investigations of the pigment were made on impure 

 mixtures. Zopf not only succeeded in isolating practically pure crys- 

 tals of the pigment from Trentepohlia Jolithus, but also established 

 their identity in form and properties with the carotin from carrots. 

 Zopf later (1895) was led to compare the blood and violet algae from 

 a pigment standpoint. It was found that the fresh vegetation of the 

 latter presents a brighter red appearance, the cells under the micro- 

 scope appearing yellow to orange; Sphaerella pluvialis, on the other 

 hand, appears dark red-brown when fresh, even thin layers in water 

 having a blood red color, the same coloration appearing under the 

 microscope. These and other differences led to a special examination 

 of what appeared to be a special pigment in Sphaerella (Haematococ- 

 cus) pluvialis different from the carotin in the Trentepohlia. Two 

 carotinoids were found, namely, carotin proper, which Zopf called 

 "eucarotin," and a red carotinoid-like pigment which is called "caro- 

 tinin," the latter being the predominating pigment. 



Special interest attaches to this red "carotinin." Its properties, as 

 described by Zopf, are characterized by combining readily with alka- 

 lies and by showing only one wide spectroscopic absorption band at 

 the F line. In other respects it has the class characteristics of a 

 carotinoid. Some doubt, however, is thrown upon the alleged alkali 

 combinations of the red "carotinin" described by Zopf by the obser- 

 vations of van Wisselingh (1915), who made a special study of the 

 response of the blood algae to mirrnrhrmical crystallization tests, as 

 well as the effect of various reagents on the pigment crystals. Three 

 carotinoids were found. The Molisch alkali method applied to the 

 green spores of the algae gave red platelets insoluble in phenol- 

 glycerin (a xanthophyll solvent) and orange needles soluble in phenol- 

 glycerin, indicating the presence of carotin and xanthophyll. The 

 red spores when treated with the Molisch reagent gave red-violet 

 crystal aggregates which contained two pigments, one an orange 



