438 ANATOMICAL TECHNOLOGY. 



Nip off the supraocclpitale, including the dura, as far as the 

 Crista lambdoidaUs. Then nip off the crista itself in its whole 

 extent until the attached border of the bony tentorium is seen to be 

 free from the parietalla. Then divide the ventral ends of the ten- 

 torium as follows : — 



Hold the head with the ventral side down, support the caudal 

 divisions of the brain with a disengaged finger, and with tracer and 

 scissors separate the cephalic surface of the cerebellum from the 

 tentorium. 



Introduce a nipper blade between it and the hemisphere on 

 either side, in such a way that the greater convexity is toward the 

 hemisphere rather than the cerebellum ; the cut is to be made at 

 the level of the Sutura sq^uimosa ; the width of the tentorium at 

 this point is about 8 mm., and the nii)per blade should not be intro- 

 duced to a greater depth than that, for fear of injuring the optici. 

 In closing the blades, the head should be held very firmly so that 

 no rotation may occur. The detached tentorium may be extracted 

 by the forceps, or by the nippers used as forceps, any adhesions 

 being carefully separated with the tracer or scissors. 



Hold the head over the 7 per cent, brine, with the ventral side 

 down, and nip out, piecemeal, a triangular piece of the calva. 

 The mesal adhesions of the dura may be divided with the scissors, 

 but elsewhere the dura is to be left upon the hemispheres. As the 

 hemispheres begin to fall, hold the head so that they are supported 

 by the brine, and then snip all remaining adhesions until the entire 

 brain is free and floats in the liquid. 



§ 1104. Removal of the Dura. — Saturate some cotton with the 

 brine, and place it under the brain, so that about one third of the 

 organ projects above the surface. A^ioid handling and lifting the 

 brain ; move it by shifting the cotton or by grasping the dorsal por- 

 tions of the dura. Remove the dorsal and lateral parts of the dura 

 by grasping the free borders left by cutting along the dorsimeson, 

 and cutting out piece by piece with the scissors. Then grasp the 

 falx just dorso-caudad of the Lohl ol.^ at the straight transverse 

 fissure — F. cruciata ; introduce the scissors about 5 mm., and cut 

 the falx. Gently draw the cephalic portion cephalo-ventrad be- 

 tween i\\Q Labi ol.^ and remove it. Draw the caudal portion cau- 

 dad, and carefully cut all its attachments. 



Turn the brain upon its dorsal surface, and remove the ventral 

 portions of the dura with great care and in small pieces. Especial 



