112 ROYAL SOCIETY OF CANADA. 



lions. The writer has a number of sHdes of Ji- mycoides prepared 

 in this manner over two years ago, which at the time of writing 

 are as good as the day they were made. 



Colonies of yeasts, etc., do not give good preparations, as the 

 cells float away in the formalin solution or diffuse on the surface of 

 the gelatine. For colonies of this character, the gelatine plates are 

 placed in a chamber containing several ounces of formalin and are 

 left sealed for twenty-four hours. The gelatine is then trimmed and 

 the sterile cover glass is placed on the top of the gelatine. A few air 

 bubbles are apt to get in, but if care is exercised the}' may be avoided. 

 The paraffming of the slides and mountings are then carried out, as 

 already described. 



These slides may be used for examination with the naked eye, 

 hand lens or under the microscope, or they may be used in an electric 

 lantern and the pictures projected on the screen. In the last .named 

 case, they should not be left too long in the lantern. 



