2 BULLETIN 38, U. S. DEPARTMENT OF AGRICULTURE. 
the field and in the factory. It yields heavily and produces fiber 
which manufacturers of long-staple cottons have found to be very 
satisfactory in spinning quality. The experience of those who 
planted this cotton last year indicates that it can be profitably grown 
in the Salt River Valley. 
There is at present no evidence that any other cotton will be more 
profitable in this district. If in the future, evidence should be forth- 
coming that a change to some other type would be advantageous, the 
change should be made at once and by the community as a whole. 
Meantime the introduction of other sorts by individual growers 
should be discouraged, as it would surely spell disaster to a promising 
industry. 
THE EGYPTIAN TYPE OF COTTON. 
Egyptian cotton is a distinct type which bears a resemblance to the 
American Sea Island, yet it is quite different from the latter. Its 
origin is obscure, although it is generally believed to be partly of 
Sea Island ancestry. The fiber of Egyptian cotton is especially used 
in manufacturing goods in which great strength is required, such as 
sewing thread, automobile -tire fabrics, the better quality of hosiery, 
etc. ; also the finer grades of cotton cloth, for the production of which 
long and fine fiber is demanded. 
The history of cotton growing in Egypt has been marked by the 
appearance of one variety after another. Each of these gave very 
satisfactory results at first, but soon " ran out," owing to the failure 
of the growers to keep their seed pure. About 30 years ago the Mit 
Afifi variety came into prominence, and in 1912 this variety still con- 
stituted 25 per cent of the entire crop of the country. Its lint is of 
medium length (1| to If inches) and is distinguished by its deep buff 
color. The Mit Afifi variety is often referred to by the trade name, 
" Brown Egyptian." In the last 10 years it has deteriorated rapidly 
and no longer holds its former high place in the estimation of cotton 
spinners. More recently, longer linted varieties, of which Janno- 
vitch, Nubari, and Sakellaridis are the most important, have been 
successively developed. Of these, Jannovitch and Nubari have 
already begun to run out. Sakellaridis, on the other hand, is of 
such recent origin that there has been less opportunity for mixing 
and deterioration. 
Each of these varieties apparently originated suddenly with a 
single very distinct plant growing in a field of some older variety. 
The origin of a variety in this manner is termed by plant breeders 
" mutation," or " sporting," and the new type thus developed is 
usually so different from the parent variety that no relationship 
would be suspected if the origin were not known. Mutations are 
