THE COTTON PLANT 85. 
precaution, such as chequerboard plots, differential 
irrigation, plant-development records, and statistical 
treatment. The result had three main aspects: first, 
the State aspect, by showing that the conventional 
practice of the Egyptian native in not planting very early 
was the correct practice under the existing climatic and 
agricultural conditions ; secondly, the utilitarian aspect, 
by systematising the routine of propagating valuable 
pure-strain seed so as to involve the minimum risk of 
damage or loss, either to the seed put into the ground, 
or of the expected harvest. Lastly, and most im- 
portant, it showed up a gap in our knowledge of the 
relation between temperature and the permeability 
of protoplasm, because the observed facts were only 
explicable on an hypothesis that the permeability of 
root-hairs as well as the growth of the root was a loga- 
rithmic function of the soil temperature; the only 
existing scientific data (Von Rysselbergh) showed no 
such simple relation. Subsequently and independ- 
ently this relation was actually found (Delf) in purely 
laboratory work directed solely to the study of proto- 
plasmic permeability, using for convenience the hollow 
flower-stalks of dandelion and leaves of onion; the 
gap in our knowledge was thus filled up, and the new 
knowledge is of importance, not only to cotton and to 
all agriculture, but to all our knowledge of Life ; as 
a current example, it may be applicable to the technique 
of asepsis during irrigation treatment of wounds. 
The field of science in relation to the cotton indus- 
tries has two main divisions, the study of the Plant as 
a producer of cotton hairs, and the study of the cotton 
