930 Hazen: Lire HISTORY oF SPHAERELLA LACUSTRIS 
chrom and further defined it as a substance different from the color- 
ing matter of the red algae (which is soluble in water) and the purple 
pigment found in many Oscillatoriaceae. He inferred that haemato- 
chrom is a substance very closely related to chlorophyl since at 
certain times it appears to be built up directly into chlorophyl ; he 
also supposed that the coloring matter found in 77 a de imd and 
the red *' eye-spots" of zoospores was haematochrom. 
 Rostafinski ('81)* declared that Haematococcus in the snow- 
fields of the Alps never grows green, but the green appearance 
sometimes ascribed to it is due to a species of Chlamydomonas ; 
since, however, the red cells increase rapidly, he thought it was 
clear that their plasma could assimilate without chlorophyl and 
without organic matter in solution.  Rostafinski, furthermore, ex- 
tracted the red pigment (apparently from Trentepohlia) and find- 
ing that it had a spectrum similar to that of chlorophyl and also 
became green when exposed to light, he concluded that it was a 
reduced chlorophyl, and in order to indicate this relationship sug- 
gested for it the name chlororujin. 
During the next year Engelmann ('82) made careful investiga- 
tions to confirm or overthrow Rostafinski's assumptions. By 
means of his bacterial method} he proved that the pure red cells 
are able to decompose carbon dioxid under the influence of light, 
but the reaction was stronger in the greener cells. Next, by re- 
search in the microspectrum, Engelmann found that even in the 
case of the red cells the rays most effective in photosynthesis are 
those which his previous experiments] had shown to be the most 
effective in the case of green cells, viz., the red rays between 8- 
and C. Finally he found that the pure red cells gave a strong 
continuous absorption from the yellow to the violet end of the 
* It should be noted that Rostafinski considered the ** red snow’ oss Sphae- 
rella nivalis (Bauer) Sommerf. identical with his Haematococcus lacustri. 
A drop of water filled with red cells of Haematococcus was mixed d a drop con- 
taining many active bacteria and mounted under a cover-g'ass and sealed with vaseline. 
When placed in the light, after a few minutes most of the red cells were surrounded by 
swarms of bacteria eagerly seeking the oxygen given off by the cells through the de- 
composition of DS under the influence of light acting on the coloring matter. In the 
dark the m quickly stoppe ; 
TI wW Tanet. Über t Sauerstofianscheidung von Pflanzenzellen im Mikro- 
spectrum. Bot. Zeit. 40: 417-426. 1882, (See Vines, Physio’ ogy of Plants, 225- 
257. 1886.) 
* 
