20-J 



A New Form of Microtome Knife. 



By E. G. Martin. 



The writer has been much impressed, botli as student and teacher, 

 with tlie great waste of energy and time involved in Iveeping microtome 

 knives in satisfactory condition for use. In every biological laboratory the 

 care of these Ivuives is recognized as constituting a serious drain upon the 

 student's time. In most undergraduate laboratories there is also apt to 

 be more or less disposition to use poorly sharpened knives, rather than 

 take the trouble to put them in satisfactory condition, with the inevitable 



Microtome Knife.— In this drawing the two blades are shown clamped together in 

 position for use. but without the cutting: blade inserted. When the set-screw is loos- 

 ened the front blade falls forward far enough to allow of the insertion of the cutting 

 blade. 



consequence of inferior sections. In order to insure that the student shall 

 always be provided with a satisfactory cutting edge, and at the same time 

 to avoid the expenditure of time necessary when the usual form of knife 

 is used, the writer devised the instrument herein described for use in the 

 biological laboratories of Purdue University. 



The apparatus makes use of the patent safety razor blades which are 

 now on the market at a moderate price. The form for which this instru- 

 ment is adapted is the one which first appeax-ed on the market. The 



