Page:The Harveian oration 1903.djvu/42

 points of which appear as individual granules." 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," have not met with universal acceptance, and there are still those who regard these relatively coarse