empirical methods to come to various new conclusions probably the most important knowledge obtained appears to be that degerming is achieved to an optimum extent if on the one hand the working space is precisely defined and preferably has a cylindrical annular shape and on the other hand the product is driven through the working chamber with a whirling or turbulent action and the actual degerming work is carried out by a large number of edges 17 18 for it has been found that the number of blades 16 only indirectly influences the degerming work but the number of edges 17 18 have a direct influence it was possible to prove this by sawing out the central portion 19 of all the blades in an experimental apparatus since a relatively soft steel was chosen for this experiment the effectiveness of the edges could be demonstrated not only by the result of the work but also by the considerable abrasion of the edges as shown with the chain dotted lines 20 and 21 a further point is considered to be that surface portions f which have a product conveying action are present and more particularly the thickness of the blades 16 is sufficiently great for example up to 1 cm or more this is not only a question of strength but it gives a doubling of the effective edges 17 18 the blade 16 shown in fig5 also has a hole 22 to allow the.