422 
all important publications that have appeared 
recently. 
The second journal, The International Jour- 
nal of American Linguistics, is edited by F. 
Boas and Pliny E. Goddard, with the assist- 
ance of Professor Uhlenbeck, of Leiden, and 
Dr. W. Thalbitzer, of Copenhagen. The first 
number of the journal contains a brief intro- 
‘duction setting forth the object of the journal. 
Special articles which have so far appeared 
deal with the languages of Central America 
and North America. In the reviews a sum- 
mary of work done by the Bureau of Ameri- 
ean Ethnology is given. 
F. B. 
SPECIAL ARTICLES 
THE RELATION OF THE PLANT TO THE 
REACTION OF THE NUTRIENT SOLUTION 
One of the important factors to be con- 
sidered in plant nutrition studies is the re- 
action of the nutrient solution. The deter- 
mination of H ion concentration is of value, 
not only because of its general relation to 
plant growth, but also because of its bearing 
on the nature of selective absorption of ions. 
At the present time various misleading state- 
ments exist in the literature with regard to 
these points. In many cases principles which 
are elementary to the physical chemist have 
not been sufficiently appreciated by the agri- 
cultural chemist. In the course of extended 
studies conducted by this laboratory to deter- 
mine some effects of concentration of the 
nutrient solution on plant growth and absorp- 
tion, opportunity has been afforded for ascer- 
taining the exact reaction of the nutrient 
media under widely varying and carefully 
controlled conditions. The purpose of the 
present article is the discussion in a prelim- 
inary way of this phase of the investigation. 
It is a quite common impression that the 
plant by selective absorption may so alter the 
reaction of the nutrient solution as to produce 
extreme alkalinity or acidity. For example, 
Palladin? in describing water culture experi- 
ments states: 
1Palladin, W., ‘‘Pflanzen physiologie,’’ Berlin, 
1911, p. 82. 
SCIENCE 
[N. 8. Von. XLVIII. No. 1243 
Wiihrend der Vegetation muss dafiir gesorgt wer- 
den, dass die Kultur fliissigkeit nicht alkalisch wird. 
Zur Beseitigung der alkalischen Reaktion wird so 
lange schwache Phosphorsiurelésung zugesetzt, bis 
die Lésung schwach sauer reagirt. 
Also it is often ‘claimed that from KOl, 
K,SO,, and similar solutions the cation is 
removed at a rate so much faster than that of 
the anion that a marked acid reaction ensues, 
which may result in injury to the plant. Con- 
versely a NaNO, solution is said to become 
alkaline. The evidence on which these ideas 
are based is very slight. Some of the experi- 
ments quoted were performed many years ago, 
when chemical methods and principles were in 
a relatively imperfect stage of development. 
The condition of acidity of alkalinity in most 
of the investigations has been measured by 
various titrations, which for this purpose are 
subject to misinterpretation, as pointed out 
in a previous article.2 
In the latter investigation experiments with 
barley seedlings indicated a strong tendency 
on the part of the plant to change the re- 
action of various potassium phosphate solu- 
tions in the direction of neutrality; either 
acid or alkaline solutions soon attained a H 
ion concentration equivalent to approximately 
Px 7.0, while neutral solutions remained un- 
altered in reaction. These experiments have 
now been extended to other solutions including 
complete nutrient solutions, and observations 
have been made at all stages in the growth 
eyele of the barley plant. Also several va- 
rieties of beans have been used. The experi- 
ments were carried out by means of sand and 
water cultures, which will be described else- 
where. It will suffice to state here that the 
technique was such as to permit of the pro- 
duction of normal, well matured plants. In © 
every instance, without exception, nutrient 
solutions with an acid reaction reached an 
approximately neutral reaction after contact 
with the plant roots for varying periods of 
time. Even where plants were grown to matu- 
rity without change of solution, the neutral 
2 Hoagland, D. R., ‘‘Soil Science,’’ Vol. III., 
No. 6, pp. 547-560, 1917. 
