296 MENDOZA, RAMIREZ, AND ENRIQUEZ. 



PREPARATION OF BRAIN MODELS. 

 By Pio Valencia Eneiquez. 



The blotting-paper pulp is prepared as described in the work of 

 Mendoza and Eamirez. The two hemispheres of a brain are then 

 separated with a sharp, thin-bladed Tcnife, and four vertical-longitudinal 

 (sagittal) sections of one hemisphere made, the cuts being 1.5, 3, and 

 4.5 centimeters, respectively, from the mesial surface. The mesial sec- 

 tion is then placed on th.e table and an exact outline of the structures 

 found on each of its two surfaces drawn through transparent paper. 

 Two pieces of blotting paper are cut from these outlines. A sufficient 

 quantity of the macerated blotting paper is then put on the table, and 

 compressed with a flat board until it becomes somewhat solid and nearly 

 as thin as the mesial brain section. Its exposed surface is now ready 

 for a coat of library paste which is first put on thin, then thick, and 

 the proper blotting paper outline is then attached to this by compression. 

 The other surface is treated in like manner and the remaining sections 

 are made in the same way. 



The exposed borders are then trimmed, the gyri, sulci, and ventricles 

 being modeled while the material is soft and plastic, all exposed surfaces 

 being coated with library paste. 



Drying. — The models dry better in the shade than in the sunshine, 

 rapid drying causing them to warp and to lose their shape. They 

 should be placed in a closed locker over a pile of blotting papers on 

 a plane surface. The mixlel should be turned once or twice each 34 

 hours and the blotting papers should be replaced with dry ones at 

 the same time, in order to facilitate the drying process. After the 

 models are dry they may be painted in any A?ay desired. 



Caution. — All models made in this way must be preserved in closed 

 cases, especially in the tropics, in order that rats, roaches, and other 

 vermin may not mutilate or destroy them. 



