34 BOTANICAL GAZETTE [ JANUARY 
last used. Before the error was discovered, Cucurbita Pepo had 
been tested’as shown in the following table, the explanation of 
the columns of figures being the same as for the preceding table, 
~and the salts held in gelatin blocks as before. 
Curved Neutral Curved 
KNO, _ 3 19 7 = Na,HPO, 
Ca(NO3). “ = 9 I ee Na,HPO, 
MgSO, w oO 8 fe) “ Na,HPO, 
It is probable that the results would have been approximately 
the same in the last table if the solutions of salts on the opposite 
sides of the roots had been osmotically equal. Lupinus albus was 
tested in precisely the same way and with the same chemicals as 
given in this table, and the result showed thirty roots out of 
thirty-seven curved toward the sodic salt, and not one root 
curved toward the three other chemicals. 
From the two foregoing tables, this result certainly stands 
out: Cucurbita Pepo is neither attracted nor repelled by the 
chemicals used as is Lupinus albus. If its direction of growth Is 
controlled at all, itis but feebly so by the di-sodic phosphate 
and the calcic nitrate; but it is more probable that it is not 
chemotropic, at least toward the salts here used, and that the 
curves that came were due to disturbances of growth, not falling 
within the realm of chemotropism. 
CONCLUSIONS, 
The experimental results recorded in the foregoing pages 
Show that the roots of Lupinus albus are chemotropically posi- 
tive toward solutions of di-sodic phosphate, and that no concen- 
tration of solution of this salt will produce a negative curve. 
The stronger solutions used (1.5 per cent.), cause first a curving 
toward the salt and then death. The death of the roots in such 
a solution may be due to the osmotic strength of the surrounding 
medium. The osmotic strength of the salt solution plus that of 
the gelatin probably amounts to somewhat more than four atmos- 
pheres of pressure, and such a pressure is probably greater than 
that of the cells of the distal millimeter of the root-tip.% 
3STANGE: Bot. Zeit. 50: 292. 1892. 
