474 Transactions of the Society. 



XII. — Description of a Simple Plan of Imbedding Tissues, for 

 Microtome Cutting, in Semi-pulped TJnglazed Printing 

 Paper. By B. Wills Richardson, F.R.C.S.I., Vice- 

 President University of Dublin Biological Association. 



(Rsad 10th May, 1882.) 



I am emboldened to publish the following description of a method 

 for imbedding tissues of suitable consistence for microtome cutting, 

 as it may have some claim to originality, imbedding in semi-pulped 

 paper being unnoticed in any of the standard works on microscopic 

 manipulation which I have had opportunities of searching. Be 

 this as it may, very thin and perfect sections can be cut with 

 rapidity in semi-pulped paper, from either animal or vegetable 

 structures of sufficient firmness to remain uninjured while being 

 sent home in the microtome well. I think, however, that im- 

 bedding in semi-pulped paper will probably be found to have a 

 more extended range of usefulness for vegetable section- cutting 

 rather than for cutting animal structures. 



Although tissues submitted to the process should have a certain 

 amount of firmness, as I have just observed, they should not, on 

 the other hand, be so dense as to offer much resistance to the 

 knife, very unresisting structures being unsuitable for this mode of 

 imbedding. 



The diameter of the tissue to be cut should, when feasible, be 

 one-quarter of an inch less than the diameter of the microtome 

 well. Indeed, a microscopist's laboratory ought to be provided 

 with microtomes having well's of different diameters that both time 

 and tissues may be economized. 



Stems of plants previous to cutting may, with advantage, be 

 stored in methylated spirit for a few weeks ; and animal structures, 

 in whatever fluid has been found most appropriate for their pre- 

 servation and, if necessary, for their hardening. 



I shall now give the steps of this easy method : — 

 Cut strips, eight to nine inches long, from white unglazed 

 printing-paper, the width of each strip to be a little more than the 

 length of the structure to be imbedded. Transfer the latter from 

 the preservative fluid to filtered water, in which leave it for about 

 half an hour, then dip one of the strips of paper in the water for 

 a few seconds, remove it and drain the water rapidly off its surfaces. 

 Take the structure to be cut out of the water, apply one end of the 

 wetted paper to a portion of its circumference, and roll the paper 

 around the structure as closely as the paper will allow of without 

 tearing. If necessary, apply more wetted paper until both the 

 paper and inclosure form a plug that should require a little 



