THE BLUE ALG 471 
passing to a more detailed examination of the higher alge it 
will be most instructive for us to study some of the simpler 
forms. About as simple as any are the exceedingly minute 
plants which for want of a better name we may call tint-ball 
algze (Chroécoccus), and which when highly magnified present 
Fic. 305.—Tint-ball Alga (Chroécoccus turgidus, Tint-ball Family, Chroécoc- 
cacee). A, plant as ordinarily seen; magnified about 400 diameters. 
The inner shaded mass of protoplasm is bluish green, surrounded by a 
transparent gelatinous envelope. B, same, beginning to divide into 
two plants. C, the division advanced by the formation of a double 
wall between. D, the division complete. (Redrawn from Kirchner.)— 
Found in swamps and on wet rocks throughout the world. 
the appearance shown in Fig. 305. An individual (A) consists 
merely of a spheroidal mass of rather firm consistency and 
blue-green color, surrounded by a transparent gelatinous 
envelope. Near the center of the mass may be seen under 
favorable circumstances a comparatively small, somewhat 
denser spot. After the plant is dead, the application of pure 
water dissolves out a blue substance—called phycocyanin 1— 
leaving the yellow-green chlorophyll. This in turn if dis- 
solved out by alcohol leaves a colorless, minutely granular 
material which examined chemically would be found to 
consist of a highly complicated mixture of proteids. To such 
a mixture of organized proteids the name protoplasm ? has 
been given. This when active forms the living part of the 
plant. Whatever is alive in any plant or animal is protoplasm. 
Hence protoplasm has been called “the physical basis of 
1 Phyco-cy’an-in < Gr. phykos, seaweed; kyanos, blue. 
2 Pro’to-plasm < ML. protoplasma, the first creature made < Gr. 
protos, first; plasma, anything formed. 
