1^ DISSECTION OF THE BRAIN. 



Erlickis" liquid for a month or more, then -wash them 

 well ill ivater and keep in Zoi alcohol. One should be 

 divided longitudinally by a cut through the great longi- 

 tudinal fissure and the corpus callosum, and tlie other 

 should be divided into a series of cross-sections, each 

 about \ in. thick, from the aiiterior to the pos- 

 terior end of the brain. After having dissected an 

 alcohol brain according to the following directions the 

 study of these cross and longitudinal sections loill prove 

 very instrtictive in giving the proper relations of the 

 different parts to one another. 



A. THE BRAIN MEMBRANES. 



1. The Dura Mater will be exposed in removing the 

 brain. It is the tough membrane lining the inside of 

 the skull. It projects in between the lobes of the 

 cerebrum as a vertical fold, the falx cerebri, and as a 

 transverse fold, the tentorium, between the cerebrum 

 and cerebellum. 



2. The Pia Mater is a much thinner membrane, 

 closely investing the brain ; it is very vascular, since the 

 blood-vessels supplying the brain are carried in it. 



* The composition of these liquids is as follows : 



miller's liquid. 



Water loo parts 



Potassium bichromate 2 parts 



Sodium sulphate i part. 



ERLICKI'S liquid. 



Water lOO parts. 



Potassium bichromate 2| parts. 



Copper sulphate \ part. 



The brains should be immersed in a relatively large quantity of these 

 liquids, and during the first week of the hardening the liquid should be 

 changed either every day or every second day. The Erlicki's liquid acts 

 more quickly and is probably the better one of the two to use. 



