1921] SCHERTZ—MOTTLING 85 
MEYER found that the protein of the palisade cells is located 
chiefly in the chloroplasts, which he looks upon as the birthplace 
of the proteins, hence one can see why the color of the leaves and 
the protein content are so intimately related. He observed also 
TABLE I 
COMPARISON OF CHLOROPLASTS OF PALISADE CELLS IN Tropaeolum 
Color of leaves pag k | Deep green Green Bright green} Yellow 
Relation of diameters.... 126 100 86 72 52 
Relation of volumes. .... 200 100 64 38 14 
that as the leaves yellowed there was little change in the size of the 
nucleus, the nucleolus, or in the protein content of the cytoplasm. 
He inferred that the formation of chlorophyll in the chloroplasts 
follows the development of protein in the leaves. 
CULTURES 
The plants were grown in the purest fine quartz sand, in new 
4-inch flower pots. Experiments were conducted in which the 
sand was watered with nutrient solutions bearing all of the necessary 
elements for plant nutrition, or lacking either Ca, Mg, P, Fe, or N. 
Twenty-six plants were used in each of the six sets, making 156 in 
all. The set of plants receiving the complete nutrient was watered 
with Pfeffer’s solution as given by Duccar (14). When iron, 
calcium, magnesium, phosphorus, or nitrogen was omitted from the 
complete solution, the salts suggested by DuGcar were substituted. 
In the solution lacking iron, Ca(NO,),, KNO,, MgSO,, KCl, and 
KH,PO, were used; in that lacking magnesium, KNO,, Ca(NO,)., 
Na,SO,, FeCl;, KH,PO,, and KCl; in that lacking phosphate, 
Ca(NO;)., KNO,, MgSO,, KCl, and FeCl,; in that lacking nitrate, 
CaCl, KCl, MgSO,, KH,PO,, KCl, and FeCl,; in that lacking 
calcium, NaNO,, KNO,, MgSO,, KH.PO,, KCI, and FeCl,. All 
of these were made up according to Duccar. Cuttings were made 
of the plants, which were then rooted in sand for two weeks. The 
freshly potted plants were watered first with nutrient solutions 
and then every morning with distilled water. About every week 
another application of the nutrients was made. The plants were 
