456 The American Naturalist. [June, 



spirals in three bundles and almost so in a fourth. Several 

 nodes have been cut. The stain is deepest in these parts of 

 the stem and more widespread in the walls of the pitted ves- 

 sels. Ninety cm. up. — There is still a trace of stain in three 

 bundles ; in one it is restricted to the walls of the spiral ves- 

 sels, in the other two it does not occur in the spirals but on 

 one side of the xylem, midway out in one, and in the outer 

 angle of the other. Some of the branches were also examined. 

 The branch 65 cm. long, separated from the parent shoot only 

 ten centimeters above the cut surface. At 20 cm. from its 

 junction with the main shoot, 7 bundles showed a trace of 

 stain in the xylem part; in two of these the stain was re- 

 stricted to the spirals, and in the other five it seemed to have 

 diffused outward from the spirals into the neighboring pitted 

 vessels. Twenty-three cm. up. — Only slightest trace of stain, 

 restricted to the spirals of one bundle. Twenty-five cm. up. — 

 Not a trace of stain. The branch 105 cm. long, separated from 

 the parent shoot 41 centimeters above the cut surface. It was 

 first cut at the junction with the main stem. Here the stain 

 was to be seen in 7 bundles, but very slight and almost wholly 

 restricted to the spiral vessels. Thirty cm. from the junction, 

 i. e., past several nodes. — Stain in xylem of all of the nine 

 bundles ; restricted to the spirals in 6, diffused in 3. This cut 

 was made just above a node. The stain appears to be more 

 restricted to the spirals in the internodes than in the nodes. 

 Vessels empty. Sixty cm. up. — Only the slightest trace of 

 stain in one bundle, so slight as to be readily overlooked. 

 Sixty-five cm. up.— Color still present but so slight that no 

 one would recognize it unless informed that stain had passed 

 through the stem. Seventy cm. up. — All trace of the stain has 

 disappeared. 



It will be remembered that this vine was in the 1 per cent 

 eosine water nearly 24 hours, during which time there was no 

 perceptible lowering of the liquid, consequently all of the in- 

 ternal stain is readily accounted for, especially when we re- 

 member the powerful tinctive character of eosine, by the few 

 drops of stain which managed to get past the gelatine plugs. 

 We are warranted, therefore, in concluding that not a drop 



