Feb, 2,1924 
Tissue Fluids in Cotton 
269 
Egyptian cotton in Arizona and of the investigation of cross- and self- 
fertilization as related to the maintenance of purity of strains by Kearney 
(39). These furnish a key to the more important literature. The con¬ 
tents of a number of chemical papers on the cotton plant do not in¬ 
terest us in this connection. 
Limiting our attention to the very meagre literature of the relationship 
of the cotton plant to soil salinity and dryness, we may note that 20 years 
ago Kearney and Means (42) found that in fields in the neighborhood of 
Alexandria, Egypt, where the washing used in reclamation had not yet 
been completed, the salt content of the upper 2 feet of the soil was, 
among good plants, 0.6 per cent; near occasional plants in partly bare 
ground, 1.8 per cent; on wholly bare ground, 2 per cent and higher. 
“ These figures indicate an exceptionally high degree of resistance in the 
cotton plant, marking it as one of the very foremost in this respect of the 
world's great crops." Further nonquantitative notes on the occurrence 
of cotton on saline land are given. 
Finally, Kearney (36) has discussed the growth of Egyptian cotton 
on alkali soils. His results indicate that with alkali of the type found at 
Sacaton the fruitfulness of the plants is likely to be impaired when the 
salt content exceeds 0.4 per cent of the dry weight of the soil. This, he 
concludes, would seem to be about the limit for profitable production of 
this crop in the presence of alkali of the type found at Sacaton, although 
he observed that the quality of the fiber does not necessarily suffer in 
the presence of 0.55 per cent of salt. He found that the moisture capacity 
of the soil is an important factor in determining the size, vigor, and fruit¬ 
fulness of Egyptian cotton plants. The alkali resistance of Egyptian 
cotton is relatively high when other conditions are favorable. It would 
appear that a fair yield of fiber of good commercial quality can be obtained 
when nearly one-half of 1 per cent of the total dry weight of the soil 
consists of readily soluble alkali salts, provided that carbonates are 
absent or form only an inconsiderable proportion of the total mineral 
solutes. 
The only literature on the salt content of the Egyptian cotton plant 
of which we are aware consists of two short papers by Balls (5, 6), 
both of which came to our attention after this manuscript was practi¬ 
cally completed. 
In the first of these (5) he calls attention to a chance result which 
indicates that the tree cottons and Egyptian cotton bring up from 
deeper layers and deposit on the surface of the soil through the shedding 
of their leaves sufficient quantities of substances, of which NaCl is one 
constituent, to render the soil unsuitable for other plantings. 
In the second (6) he compares the chlorid content of three pure strains 
of Egyptian cotton grown at Gizeh, Egypt, on land which contained not 
more than 0.1 per cent of NaCl in the surface layers, even after long 
deprivation of water. From these analyses, which are few in number 
and based on the dry weight of the leaves only, he concludes that Egypt¬ 
ian cotton growing under typical field crop conditions has a salt content 
which indicates a concentration of 0.3 per cent NaCl in the leaf cell sap. 
This concentration varies with the salinity of the soil, though not pro¬ 
portionally. It also varies with the particular pure strain or variety. 
Plants of two Egyptian strains growing with interfering root systems 
may show differences of as much as 10 : 7 in the salinity of their cell sap. 
This fact, he suggests, may have some utility in the breeding of strains 
for the salty lands of the northern delta of Egypt. 
