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for examination to Professor Winki^eh, who had the kijidness to 

 leave its furtiier eUxboration to me. 



Since the sections, that should he made subsequently, were to be 

 stained after the Weigert — Pal method, the cerebellum was immedia- 

 tely after its arrival in Amsterdam refixed in Mult,er's liquid. It 

 was only when this had been performed that the photographs were 

 taken (fig. I and II). 



The -white spots that are seen on the figures, were caused by 

 celloidine, by means of which the pieces were pasted together. It 

 was necessary to do this, because the cerebellum, was received here 

 being cut into three pieces. 



In the middle of the surface of the cerebellum we observe a ca\'ity. 

 If this cavity is divided into four parts along the longitudinal axis of 

 the cerebellum, nearly one quarter is lying to the left of the median 

 line, two other quarters are lying \n the right median part, and another 

 quarter (probably the smallest one) is lying in the right lateral part. 



The form of this cavity on the surface of the cerebellum, as far 

 as it is lying in the median portion, is nearl}- that of a truncated 

 isosceles triangle having for its basis the paramedian line. 



The greater part of this triangle (nearly three quarters) is lying 

 in the right half, and only one fourth in the left half of the cerebellum. 



What imports most now is to find out to which subdivision of 

 the cerebellum belong the convolutions from which van Rijnberk 

 has extirpated this small piece. 



In fig. I and II, next to the defect (fig. II sub 1), our attention 

 is drawn immediately by a deep furrow (fig. II sub 2a), that has 

 become to all probability more clearly visible by the process of 

 fixation, than may have been the case during life. 



The sulcus primarius is the furrow penetrating deepest to the 

 medullary nucleus and continuing forwai-d till near the sinus Rhom- 

 boidalis, causing in this way the lobus anterior and the lobus 

 posterior to be connected, for by far the greater part, only by a 

 ridge of medullated nerve-substance. We may therefore safely assume 

 that, the cerebellum having been eventually shrivelled, this sulcus, 

 lying between two portions so deeply divided, will become more 

 distinctly visible. 



At first view therefore we might hold the furrow indicated sub 2a 

 fig. II, to be probably the sulcus primarius. Such being the case, 

 all that is lying before this furrow would be lobus anterior, all 

 that is lying behind it lobus posterior. 



On examining the anterior portion, this is found to consist of two 



