n8 



BACTERIA IN RELATION TO PLANT DISEASES. 



The writer passes material designed for sections from alcohol through chloroform 

 (or xylol) into paraffin. Chloroform is preferred in case the infiltration is to be 

 completed in vacuo ; otherwise xylol is generally employed. A mixture of xylol 

 and alcohol is first used, then pure xylol, after this xylol with as much paraffin as 

 can be dissolved in it cold. The vial is then placed on top of the paraffin bath and 



Fig. 105* 



shaved paraffin added until it will dissolve no more at this temperature ; the material 

 is then placed inside the apparatus in pure melted paraffin, and it is finally mounted 

 from a second dish of pure paraffin. The temperature of the paraffin bath is usually 



*Fic. 105. A small paraffin oven much used in the writer's laboratory. The capacity of the 

 chamber is 6 by 7 by 5 inches. The thermo-regulator is like that shown in fig. 35, but with chloro- 

 form substituted for glycerin. 



