INTERNAL ECONOMY OF THE SEA 87 
by animals they are raised to a still higher incar- 
nation as animal proteins. But when the plant or 
animal dies the complex organic substances are 
broken down through the agency of bacteria into 
simple constituents once more, and some of these 
being utilized by plants may enter again into the 
circle of life. Shakespeare, with his prescience, 
spoke of what might happen to the dust of Cesar, 
but it was only a vague vision that he can have 
had of the long nutritive chains, with quaint 
sequences like those of “The House that Jack 
built,” which connect Diatoms and débris with 
fishes and man. As Professor Herdman tells us, 
man eats the cod, which in turn may feed on the 
whiting, and that on the sprat, and the sprat feeds 
on Copepods, which again depend on Peridinians 
and Diatoms. Most of the nutritive chains bring us 
through Copepods to sea-grass and seaweeds, to 
Diatoms and débris. For so the world goes round, 
and such are the incarnations of the sea. 
