LIFELESS MATTER IN LIVING CELLS. 19 



the number of lifeless substances which may thus appear within 

 the cells both of plants and animals. 



The second case is of less importance, though of common oc- 



FIG. 9. A group of cells from the stem of a geranium 

 (Pelargonium), showing lifeless substances (starch and 

 crystals) within the protoplasm. As in Fig. 2, each cell 

 contains a large central vacuole, filled with sap; c, 

 groups of crystals of calcium oxalate; i.e., intercellular 

 space; n, nucleus; s, granules of starch. ( x 300.) 



FIG. 10. (After Ranvier.) Group 

 of "adipose cells" from the 

 tissue beneath the skin (''sub- 

 cutaneous connective tissue") 

 of an embryo calf, showing 

 drops of fat in the protoplasm ; 

 /, fat-drops (black); n, nuclei, 

 (x 550.) 



currence. A good example is found in the lining membrane of 

 the oesophagus of the dog (Fig. 11), which like the human skin is 

 almost entirely made up of closely crowded cells. Those in the 



FIG. 11. Section through the inner coat of the gullet of a dog, showing: p, living cells of the 

 deeper layers ; s, lif eless cells of the superficial layers. 



deepest part consist chiefly of living protoplasm very similar to 

 that of the young pine shoot (compare Fig. 1). Above them the 

 cells gradually become flattened until at the surface they have 



