AGRONOMY: C B. LIPMAN 
477 
the diffusion of the KCl from the interior of the egg to the outside solu- 
tion is removed. 
This theory holds probably for all cases of the second group of phe- 
nomena of antagonism, namely where salts (and possibly acids) in general 
antagonize the injurious action of an electrolyte. It must remain for 
further investigations to decide whether it holds also for the first group 
of cases of antagonism where the injurious action of high concentrations 
of a salt with a monovalent cation (e.g., NaCl) is inhibited by traces 
of a salt with a bivalent cation (e.g., CaCl2). The two groups of phe- 
nomena are in one respect the converse of each other, since in the first 
group the efficiency of the antagonistic action increases with the valency 
of the cation, while in the second group the antagonistic action increases 
with the valency of the anion of the antagonistic salt. 
iLoeb, Archiv ges. Physiol, Bonn, 88, 68 (1901); ^wer. /. Physiol, 6, 411 (1902). 
2Loeb, Archiv ges. Physiol Bonn, 107, 252 (1905). 
3Loeb, Biochem. Zs., 47, 127 (1912). 
* Osterhout, Science, 35, 112 (1912); Bol Gaz., Chicago, 59, 317 (1915). 
^ Loeb and Wasteneys, Biochem. Zs., 31, 450 (1911). 
6Loeb,/6i<f., 43, 181 (1912). 
'Loeb and Wasteneys, Ibid., 33, 489 (1911); 39, 167 (1912). 
THE NITROGEN PROBLEM IN ARID SOILS 
By Chas. B. Lipman 
COLLEGE OF AGRICULTURE. UNIVERSITY OF CALIFORNIA 
Presented to the Academy. July 24, 1915 
Standing eminent, if not preeminent, everywhere, in considerations 
of soil fertility, the nitrogen problem is especially so under arid soil 
conditions. The acuteness of the situation in the latter has been recog- 
nized, however, by neither the scientist nor the practical man until re- 
cently when certain investigations on the one hand, and certain field 
manifestations on the other, have caused to stand out in sharp relief 
the nitrogen question from among others in Cahfornia's soil puzzles. 
It is with reference to some of these recent findings, and their bearing 
on problems of soil fertihty in California, that this brief paper is 
written as a forerunner of more detailed discussions soon to appear 
elsewhere. 1 
Considering only the average nitrogen-content of California soils, 
as based on a thousand or more analyses, the student of the subject 
does not obtain a true picture of the paucity in nitrogen which charac- 
terizes our truly arid soils. For many of our soils are situated in re- 
gions of heavy winter rainfall and produce a luxuriant spring growth; 
