379 



idea of incorporating a small quantity of very dilute rubber 

 solution to overcome this was a distinct advance. Given an 

 absolutely reliable imbedding medium, properly employed, the 

 next essential for successful section -cutting was a perfect edge to 

 the razor, for the least roughness here would be sure to tear and 

 dislocate the sections. The really good razor sharpener seemed 

 to be born, and not made ; at least, most of the razors returned by 

 the professional were unsatisfactory. Many years back he had come 

 across a " wrinkle " in Behren's " Hilfsbuch," where it is attri- 

 buted to Hugo von Mohl, which had answered very well indeed. 

 It was to finally polish the razor edge on a strip of plate-glass 

 with finely-powdered " Vienna lime " and water. This material, 

 which he believed was a variety of dolomite, could be obtained 

 from the importers of watchmakers' requirements in Soho or 

 Clerkenwell. Quite recently some similar material, incorporated 

 with a soapy base, was sold as " Buttercup Polish," and used on the 

 smooth side of an ordinary razor-strop. This gave a polished 

 edge to the blade, which was absolutely necessary for success. 

 The rest was a matter of personal practice. 



The President thought there was the right ring about this 

 paper, and the hints it contained would be of service to all who 

 were in the habit of cutting sections. As regarded the Cambridge 

 rocking microtome, he found that this developc^l more electricity 

 than any other, and the effect of this was very troublesome. 

 After a while this did not happen for some reason, but at first so 

 much electricity was developed that the ribbon was simply blown 

 to pieces. One great use of serial sections of such things, for 

 instance, as hyphae, was that by making drawings of these on 

 a number of pieces of paper the thing could be built up and a 

 model produced, which was a far more valuable method than any 

 other for understanding the structure of any object under exami- 

 nation. The method described by Dr. Scriven appeared to be 

 a very excellent one, and when it becamfe a matter of importance 

 to trace out a particular organ, the method by serial sections was 

 the only true way of doing it, 



Mr. Morland said he remembered that many years ago Mr. 

 Newton made a number of sections of the brain of the cockroach 

 in the way mentioned by the President, and cut them out in thin 

 plates of wood, which, when put together-, formed a model of the 

 brain. (See Journal Q.M.C, Ser. I., Vol. V., p. 150.) 



