I. INTRODUCTION The great diagnostic and prognostic importance of the sedimentation of blood corpuscles is probably well known. Of the so-called macromethods, in which blood must be taken by venipuncture, those mentioned by Westergren and Linzenmeier are best known, and at the present time the former's excellent method is presumably the prevailing one. In spite of its indisputably great merits, this method, like all the other macromethods, has its inherent weakness, viz., venipuncture. Even if in most cases this does not involve any difficulty, there are two categories of patients in whom, for technical reasons, it is often inadequate, viz., (1) corpulent people and (2) small children and babies. In the latter category it is, of course, possible with an open fontanel to obtain a sufficient quantity of blood by sinus puncture, but most pediatricians will agree that this is a step which should be reserved for occasional urgent cases,