points of which appear as individual granules."[1] The imperfect loculi formed by this disposition of fibrils were described as being occupied by a more fluid material. Objections were raised to this explanation, and the more recent description with which the name of Bütschli is associated attributes to the protoplasm a "foam-structure, which depends upon the presence within a uniform ground mass of a large number of extremely fine vacuoles lying almost at the limit of microscopic visibility, and- so close together that their walls consist of relatively thin lamellæ." (Verworn.)
But these and several other views as to the intimate structure of the living cell-protoplasm which describe it "as being composed of two substances, one of which is disposed as a contractile net according to some, as a relatively rigid framework according to others, or as free filaments; or whether it be built up of a more solid material and of a more fluid material which occupies the minute spaces or vacuoles which are hollowed out in the former,"[2] have not met with universal acceptance, and there are still those who regard these relatively coarse indica-
