INDUSTRIAL RETTING OF TEXTILE PLANTS I069 



ment forms an accessory part ; 2) those in which such addition is the 

 principal part. The process devised by the Institute of Agricultural Bac- 

 teriology of Portici, and based on the use of the pectic aerobic ferments 

 already mentioned, the prototype of which is the Bacillus Comesii (named 

 after Prof. Orazio Comes), also mentioned above will belong to the 2nd 

 group. 



This method consists in : i) immersing the textile materials in ord- 

 inary water ; 2) raising the whole to the optimum temperature of the bacil- 

 lus in question, from 28° to 350 C, which temperature must be maintained 

 during the entire period of retting ; 3) adding a sufficient quantity of pure 

 culture of the bacillus ; 4) passing an air current through the entire mass 

 during the whole period of retting. 



Theoretically, the water, the textile material and the vessels should 

 be sterilised, but this cannot be done under practical conditions. The 

 novelty and the very essence of the method in question (as was shown very 

 clearly by the long discussion, with the German Patent Office, which after- 

 wards granted the patent) consists in the fact that the air passing through 

 the mass regularises and intensifies the action of the pectic ferments. The 

 latter can in this way act rapidly as retting agents, and gain the upper hand 

 over all the other microbes present, which remain inactive. 



Any water suitable for retting as practised in rural districts is also 

 adapted for the method, and the duration of the operation ranges from 42 

 to 84 hours, according to the textile material. 



The process is very simple and it will be seen that to carry it into prac- 

 tice there are only needed : 



(i) Vats, differing very little from those used by peasants, and feed 

 pipes ; 



(2) Water for retting the substance, and also if necessary for 

 washing it ; 



(3) Heat (steam) ; 



(4) Air for retting and drying the textile material ; 



(5) Ferments. 



As regards the industrial application of this method a distinction must 

 be made, as it is more or less easy to apply according to the material 

 operated on, and each textile fabric calls for the solution of a separate 

 problem in this respect. 



Hemp. The method of retting under consideration is also applicable to 

 hemp, no matter whether the epidermis remains attached to the hemp stalk, 

 or whether it has first of all been detached from it. If there were no other 

 reason, however, in view of the great difference involved as regards cap- 

 acity of the retting plant required, it is certain that the two cases offer two 

 altogether different problems. 



Where hemp in the stalk is in question, the required plant consists of : 

 vats, a water pipe, boilers for steam production, a motor for compressing 

 air, and also, of course, Decauville engines for conveying the stalks, pumping 

 machinery for supplying and removing water, and better .still, an ap- 



