THE great practical significance of an exact knowledge of the forms of growth and extension of gliomas needs no special emphasis. For both the neurologist and the neurosurgeon this knowledge is certainly one of the most important aspects of the pathology of the gliomas. It is therefore surprising that this aspect of the problem has been rather neglected in modern research on this subject. In fact, the most penetrating observations made in this field are still those found in older papers (fi Stroebe, 1895), while most investigators of the last twenty years have been fascinated