Mr Lawrence Balls, Specific Salinity in the Cell Sap, etc. 467 
Specific Salinity in the Cell Sap of Pure Strains. By 
W. Lawrence Batts, M.A., St John’s College. 
[Read 4 May 1914.] 
_ The following determinations were made on the leaf-lamina 
of various species and pure strains of cotton growing at Giza, 
Egypt, on “sweet” land, which contained not more than 0:1 °/, 
of salt in-the surface layers even after long deprivation of water, 
except where otherwise stated. 
__ The percentages are expressed as NaCl in terms of dry-weight 
(air-dry) of leaf tissue ; dry weight is approximately 25 °/, of fresh 
weight. 
_ The method employed was to incinerate slowly in a porcelain 
erucible under a layer of calcium carbonate, dissolving, filtering, 
adding slight excess of silver nitrate, and back-titrating with 
potassium thiocyanide. In making the later analyses I have to 
acknowledge the assistance of M. Jacques Garboa. 
_ The results are strictly preliminary, my departure from Egypt 
having interrupted the work. 
— Ordinary field crop. From plots yielding about 500 lbs. of 
lint to the acre, sown with Domains Afifi variety, leaf-salt per- 
centages were 1°68, 1°65, 1:47, 1:2, 1:1. 
_ Determinations were made as to the number of leaves borne 
on, and shed by, various individual plants; these were then com- 
pared with the mean plant of the flowering-curves for these plots, 
and from these data it appears that the amount of. salt brought 
up from the deep soil and deposited upon the surface during 
a single season’s growth amounts to about 15 kilogrammes per 
acre. 
Tree cottons, and plants growing in cages (see previous 
communication) will shed about 100 kilogrammes per annum, 
which is sufficient to produce bad effects if not removed by 
drainage. 
Pure strain No. 77. This strain was cultivated over thirty 
acres of land. Determinations made in various normal places 
‘gave percentages: 0°63, 0:80, 0°76, 0°76, 0°74, 0°69, 0°65, 0°60, 0°46, 
with a mean of 0°68. 
The last three figures were obtained in a part of the land 
where there was exceptionally free natural under-drainage. 
In a clay patch, where the subsoil water was isolated, and 
exceptionally salt*, the leaf-salt of the plants was found on two 
‘samples to be 0°85 and 0°88. 
 *w.tL. B. “A study of some water-tables at Giza,” Well No. 8. Cairo 
Scientific Journal, 1914. 
