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H IRapib fIDetbot) of (preparing Ipermanent 

 Sections for flDicroecoptcal Diagnoeie/' 



By Dr. Ludwig Pick. 



^T^HE technique used in our laboratory for the microscopical 

 A diagnosis of curetted or excised material allows the prepa- 

 ration of sections cut, hardened, stained, and preserved 

 within ten to fifteen minutes — often, even, in less time. The 

 rapidity of the method offers, among pther ''advantages, the possi- 

 bility of deciding important questions bearing on the pathology of 

 the case during the anaesthesia, or even after the operation has 

 begun, as we have often successfully proved. 



We employ the Jung-Heidelberg Hobel (carpenter's plane), ether 

 spray freezing microtome, and, in fact, regard it as an integral part 

 of the method. It yields, with ease and rapidity, a large number 

 of fine, thin, and complete sections with very little waste of ether. 



The curetted or excised material is freed from blood and 

 coagula by dipping in water and then brought directly on to the 

 freezing plate of the microtome and frozen. In order that the 

 freezing should be rapid and not too severe, it is important that 

 the mass be laid flat, and not be thicker than 2 or 3 mm. The 

 breadth is immaterial up to i cm. square, or even greater. The 

 ice-block so obtained in a few seconds must be merely firm, not 

 stone hard; the knife must cut through lightly and without grating. 

 Particles from curettage may be laid on the plate, a half-dozen or 

 more at once, and sections obtained from all at the same time. 



The sections as they are cut are wiped from the knife-blade by 

 the finger-tip, floated into a 4 per cent, aqueous formalin solution, 

 and left there four minutes to harden and fix the cell plasma and 

 intercellular substance. The use of the finger instead of a brush is 

 to allow the warmth of the former to thaw the section before it 

 reaches the solution, avoiding in this way the formation of air- 

 bubbles in the tissue, which are often very annoying. As the for- 

 malin hardens at once, the disadvantages so often urged against 

 the freezing method — that is, fragility, loss of epithelial elements, 



*From the British Medical Journal ^ Jan. i6th, 1897. 



