QUANTITATIVE STUDY OF THE PURKINJE CELLS 235 



ured in millimeters and the measurements recorded on the cards 

 with the weights. 



The procedure in dehydrating and embedding the blocks from 

 material^preserved in 10 per cent formalin was as follows: 



Alcohol 50 per cent^+ Formalin 6 per cent 2 hours 



Alcohol 70 per cent + Formalin 4 per cent 15 hours 



Alcohol 90 per cent +^Formalin 2 per cent. 8 hours 



Alcohol 97 per cent 24 hours 



Alcohol + Ether, equal parts ' 24 hours 



Parlodion, 2 to 3 per cent 2 to 4 days 



Chloroform q hours 



Benzole 1 l^Q^^J. 



Benzole-paraffine 18 hours at 40°C. 



Paraffine 3 to 6 hours at 52-58°C. 



Fig. 1 Human cerebellum seen from above. The line S.S. marks the plane 

 of the section which is shown in figure 2-. 



In the experience of the writer, old formalin cerebella tend to 

 macerate easily, and the molecular layer especially shows a 

 tendency to break away from the internal granular layer. Where 

 this occurs there is always the possibility that some of the 

 Purkinje cells will drop out during the process of cutting and 

 staining. When the above procedure is followed, however, this 

 maceration is not usually found and good preparations are 

 secured. The common practice* of washing formalin material in 

 water before dehydrating makes the molecular layer more likely 

 to break away from the rest of the cerebellum, and it should 

 consequently be avoided. Material preserved in alcohol was 

 treated as above with the exception that the blocks were put at 

 once in 90 per cent alcohol without formol. 



