SCIENCE— ADVERTISEMENTS 



Again Available 



Microscopic Slide Trays 



Durably made of double weight faced cardboard. Inserts for 

 slides are numbered, have white background and are depressed on 

 either side to facilitate removal. Covers have printed record index 

 and are securely fastened with two clamps. 



No. 14427 Shde Trays — Map Form. To hold fourteen slides. Per dozen $/^.oo 

 No. 14429 Slide Trays — Map Form. To hold twenty slides. Per dozen ^3.50 



Will Corporation 



Products for Every Laboratory 

 Guaranteed "Vvlthout Reservation 



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OCHESTER, 



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