210 HAECKEL 



The cell, each single cell in each of us, is also an 

 individual, and as such is equally an object of 

 morphology. Hence it is the task of the morpho- 

 logy of organisms, not only to describe these higher 

 individualities as such, but also to look on them as 

 glass-houses, as it were, with so many shelves, 

 divisions, and smaller houses within of a lower 

 rank. These internal arrangements have to be 

 described, piece by piece, with the same fidelity. 



This will probably suffice to convey a general 

 idea of the subject. Clearly, the great work that 

 ought to form the general part of morphology at 

 this point was the precise determination of all 

 these various layers of individuality that are found 

 in the animals, plants, and protists, and, as we 

 rise upward, enter into more and more complex 

 relations to each other. 



The difference between, say, a turtle or a man 

 and the cell which combines in its millions to 

 form them is not the only one. Between them 

 we seemed to find individualised, or almost indi- 

 vidualised, links. Think of the idea of an organ. 

 What is my heart ? It is made of a number of 

 cell-individuals, like my whole frame. But these 

 cells form a sort of intermediate individuality in 

 me. We may go further. What is a segment 

 of a worm ? What is an arm of a star-fish ? 

 They have so much independence that they can 

 continue to live, rapidly producing new cells and 

 forming a new worm or star-fish of the higher 

 individual type, if they are cut off. The arrange- 

 ment is still more difficult in the case of the 



