112 
THE ORGANIC CELL 
form the mortal portion of the individual, the body — which 
after all is only an excrescence growing out like a bud from 
the immortal line of germ-plasm, and which soon ceases to 
exist ; the germ-plasm, however, continuing on and on, and 
possessing within the intricate structure of its chromatin the 
power of producing new individuals, and thus preserving the 
race from extinction. 
Between the Protozoa and Metazoa there is, as we have 
seen, a very marked difference in regard to the process of 
multiplication. In that neutral territory, however, between 
unicellular and multicellular organisms, there exist certain 
colonial forms, which in the modes of reproduction show a 
series of beautifully graded steps, which link up almost im- 
perceptibly the protozoan and metazoan forms. 
For instance, in Pandorina morum we have a freshwater 
alga which consists of sixteen cells, resting in a gelatinous 
matrix. From each of these sixteen cells two long flagellse 
project out into the water, and by the concerted lashing of 
these living oars the colony is able to move about. By a 
process of simple division each of these cells divides into 
sixteen daughter-cells ; the gelatinous matrix in which they are 
embedded dissolves, and sixteen daughter-colonies are set free. 
This process is repeated for several generations until exhaustion 
occurs, and the necessity for conjugation is felt. The sixteen 
cells forming a colony divide, each cell into eight, and these 
are set free by solution of the surrounding envelope. These 
swarm-spores consist of an oval cell, the pointed end being 
clearer than the rest, and carrying a pair of hair -like processes, 
which by their vibrations cause the spore to move about. 
Supposing the spores of one colony come near those of another 
they unite in pairs. The united pair form a more or less 
spherical cell which develops around itself a cellular envelope. 
It then passes into a resting stage. It may continue in this 
state of dormant vitality for a considerable length of time, 
but, on meeting with suitable conditions, e.g. moisture and 
warmth, the outer envelope bursts, the contents escaping in 
the form of a large swarm-spore, which soon divides into 
sixteen cells to form a new colony. 
In the case of Eudorina elegans , a form closely allied to 
