Explain Principle of Fehling's Soxhlet method (Lane-Eynon method)?

Reducing sugars are those which have free sugar groups and hence may be estimated directly by titrating the solution of the sample with Fehling's solution. Total sugars include both reducing and non-reducing sugars. Non-reducing sugars do not contain free sugar groups and cannot reduce Fehling's solution, e.g. sucrose and starch. Hence, non reducing sugars must be hydrolyzed to monosaccharides by heating with acid before titration.