Experimental and Applied 275 



elongated deviations. Chemically the ' fibres ' are differentiated 

 by their superior resistance to the attack of hydrolytic agencies. 

 It is a matter of common observation that ' fleshy ' structures 

 are more perishable than fibrous. The chemical constitution 

 of the tissue-substance of this less resistant order has been only 

 superficially investigated ; generally the parenchyma of flower- 

 ing stems may be classed with the pectocelluloses. Where the 

 fibrous raw materials are subjected to a preliminary treatment, 

 with the object of facilitating the separation of the fibres from 

 non-fibrous tissue, it is always a process of hydrolysis, and 

 usually the * natural ' or spontaneous process of fermentation. 



Thus flax and jute, to select the prominent types, are treated 

 by the process of retting or steeping. This consists in sub- 

 merging the stems in stagnant water ; a spontaneous fermenta- 

 tion is set up, with the result that the less resistant (cellular) 

 celluloses are disintegrated and broken down. In the case 

 of flax the retted ' straw ' is dried off, still containing the fibre. 

 This is separated by the mechanical process of breaking and 

 scutching. In the case of jute the bast layer is separated at 

 once from the retted stem, by the manual operation of stripping ; 

 and freed from cortex and adhering residues of parenchyma, 

 by beating the strips upon water. It may be stated generally 

 that these processes have not been systematically studied with 

 the view of localising the effects produced. An investigation of 

 the subject with the more precise methods of diagnosis now 

 available would be a most valuable contribution to theoretical 

 and industrial science. 



As an illustration of the desirability of more precise in- 

 formation, the history of the attempts to substitute the natural 

 by artificial processes, in the case of flax, may be cited. Vari- 

 ous chemical treatments of the stem or straw have been pro- 

 posed, and indeed worked. The yield of fibre in this plant 

 being relatively high (18-23 P-ct), and the value of the fibre 



T2 



