342 BOTANICAL GAZETTE [MAY 
root projected for the application of the water-jet. At frequent 
intervals water was put into the small cylinder, and this slowly 
percolated through the cotton and ran down over the root, thus 
insuring constant moisture. The water-jets were secured by 
bringing the water from an elevated reservoir through glass and 
rubber tubes to small glass nozzles passed through corks which 
were adjustable in height on small movable standards. The 
water-jets as they left the nozzles were from 0.2 to 0.5" in 
diameter. Each jet was adjustable by a screw-clamp applied to 
the conducting rubber tube. 
This method would seem to offer a somewhat delicate means 
of locating the sensory area of the root. The majority of roots 
gave a positive response, but most of the roots did not grow 
very well. This behavior may be ascribed to various factors. 
In spite of the precautions taken, the exposed roots of the seed- 
lings were not always everywhere kept covered with moisture; 
the nutations of the roots made it extremely difficult to keep 
the water-jet on a precise area, though the experiments ears 
constantly watched and readjustments made; and it was pee. 
cally impossible always to keep the water stream from circling: 
around the root, thus greatly extending the root surface exposed 
_ to the water stream. Besides these objections, it may be well. 
to note that a fine water-jet properly meeting the root _— 
_ only a very small surface, and it may be that a larger area ase 
be stimulated to bring forth a ready response. The follows 
table will present the main features of results obtained when 3 
water-jets were applied to the apical millimeter of the root-Uips— 
| TABLE VIIL. - 
GIVING RESULTS OF WATER-JETS APPLIED TO THE APICAL MILLIMETER a 
ae THE R : oe 
Species Period | Nemberol | + Curves | -“ 0 
: Brassica alba. Divs dys 4 to 6 hrs 14 6 peel 
