A pparatus 



9 



A motor, as shown in the figure, not only produces a very even 

 stroke, but leaves both hands free to take care of the ribbon. 



Microtome knives are available everywhere and, when perfectly 

 sharpened, are unsurpassed. Those who sharpen knives for sur- 

 geons can grind out nicks, but they do not know how to sharpen a 

 microtome knife and they cannot be taught; they sharpen knives for 

 Dr. Carver and Dr. Cutterout. 



FIG. 4. Spencer rotary microtome fitted with Land's apparatus for temperature 

 control, as described in the Botanical Gazette, June, 1914. 



In recent years several clamps have been devised to hold the 

 blade of the Gillette safety razor, the hard, even edge of which is 

 very satisfactory for microtome sections. After dealers had ignored 

 our suggestions, Mr. A. W. Strickler, at our request, devised the 

 form of holder 1 shown in Fig. 5. It is made of brass and can be 

 used in either rotary or sliding microtomes. The sectional view 

 shows that the two pieces of the holder are curved, a feature which 

 insures great rigidity. It is neither necessary nor desirable to have 



i This holder may be obtained from Mr. A. W. Strickler, 5654 Kenwood Avenue, 

 Chicago, Illinois, for $3 . 00, postpaid $3 . 15. 



