FEBRUARY 15, 1901.] 
aquatic species have been investigated. 
The results in general are: 
1. Plants rooted in soil exceed in vegeta- 
tion and dry weight plants rooted in sand 
or merely suspended. 
2. Plants rooted in sand or merely sus- 
pended contain starch, calcium and magne- 
sium in excess, while they are lacking in 
nitrogen, potash and phosphoric acid. 
3. Lithium nitrate is absorbed by the 
roots and conducted to the upper portions 
of the plant where it may be detected with 
the spectroscope. 
4. A volumetric measurement of root 
absorption has been made. 
The work which has yielded these results _ 
has been done by the author while a special 
assistant to the U. S. Commission of Fish 
and Wisheries. 
Positive Geotropism in the Hypocotyl: Pro- 
FEssoR HE. B. CopELanp, University of 
West Virginia. (By invitation. ) 
The curve by which the primary root is 
bent downward if it emerges from the seed 
in any other direction is usually executed 
in the hypocotyl. By decapitation experi- 
ments and by a careful study of the location 
of the curving region, with reference to the 
growing tip, itis shown that the stimulus 
causing this curve is received by the root 
tip. To distinguish between the parts 
played by the root tip and the hypocotyl 
Czapek’s terminology is adopted, the latter 
being geotropic, the former, geozsthetic- 
The positive geotropism of the cotyledon of 
the date and other plants, where it is the 
first part of the embryo to elongate actively, 
is explained in the same way ; thestimulus 
is received by the root tip, and the response 
is executed in the elongating zone above it, 
which is here in the cotyledon. 
The Toxic Action of certain Salts on Marine 
Alge: Dr. Benzamin M. Duaear, Cor- 
nell University. 
Plasmolytic studies upon some marine 
SCIENCE. 257 
algee at the Naples Biological Station de- 
monstrated that K NO, is too toxic to be used 
for such work. Thisled toa study of some 
of the common nutrient salts as toxic agents 
in comparsion with some salts of the heavy 
metals and with certain acids. 
In general the results indicate that po- 
tassium salts are much more toxic than 
those of sodium and magnesium. All 
the algze used were killed by an exposure 
of three days in 35 K,HPO, in sea water 
K,SO,, KNO,, and KCl were also toxic in a 
slightly decreasing ratio. With the mag- 
nesium and sodium salts used, and for a 
similar period of time, no injury occurred 
n 
at 5° 
much more toxic than for the fungi; and 
in general, the acids used were very slightly 
Salts of the heavy metals were 
toxie at eae With no salt tested was 
1000° 
it possible to keep the plant alive for more 
than a few hours ina solution of that salt 
isotonic with sea water. Grifithsia Schous- 
beri, G. opuntioides, Pleonasporium coccinium, 
and Chetomopha sp. were the alge used. 
Loss of Vigor in Corn from Inbreeding: Dr. 
Herpert J. WesBER, Department of 
Agriculture. _ 
In maize the loss of vigor caused by close 
inbreeding was found to be very marked. 
Seeds of Hickory King, a race grown com- 
monly in the eastern States, produced by 
inbreeding with pollen of the same stalk, 
yielded the next year at the rate per hun- 
dred stalks of 46 ears, weighing 94 pounds. 
Seeds of the same race in every way com- 
parable, but produced by crossing different 
seedlings, yielded under the same condi- 
tions at the rate per 100 stalks of 82 ears, 
weighing 274 pounds. 
In attempting to fix hybrids of Hickory 
King 9 x Cuzco or Peruvian Corn ¢, some 
ears were inbred with pollen from the 
