174 Minot: Notes on Histological Technique. III, 2. 



absolute had been recommended, At present I know of no application 

 of absolute alcoliol in liistology, wliich I can regard as anything but 

 an unnecessary extravagance. 



It is presumably the general custom to keep histological and 

 embryological material in alcoliol of 70 to 80 % ; placing it in strong 

 alcohol for a day before imbedding. In this country the rule is less 

 heeded than it should be, and it may prove advantageons to again 

 emphasize the importance of adhering to it. I have noticed particularly 

 the very slow distortion of the tissues of the human foetus, which goes 

 on if they are kept in stroug alcohol, 92 to 96 '■%. 



2. Benzole. This substance can replace the much dearer xylole 

 for clarifying sections, cleaning lenses, diluting Canada baisam to a 

 convenient consistency, etc. Pure benzole has the property of evapour- 

 ating without leaving a residue. 



3. Imbedding in celloidine. For this are needed: — 



a. Mixture of equal parts of ether and alcohol. 



b. A thin Solution of celloidine in a, This Solution should be 

 syrupy and flow easily. 



c. A thick Solution of celloidine in a. of about the consistency 

 of thick molasses. 



d. An imbedding box made by fastening a roll of paper around 

 a cylindrical cork with a pin. 



e. A sinker, which may be conveniently made, by casting a 

 piece of lead around a wire nail. 



f. Alcohol of 80 to 85%. 



In regard to these, all of which are in familiär use , the following 

 points may be noted. The mixture of ether and alcohol is very difficult 

 to keep and ought to renewed every few days, because of the loss of 

 ether. For the same reason the celloidine Solutions are best used 

 frcsh; accordiugly when from the loss of ether the Solution begins to 

 turn unclear or milky it may be poured out and allowed to dry com- 

 pletely and then be redissolved. Dirt may be removed from the Solut- 

 ion by settling and decantation. The imbedding box is like that 

 recommended by Blochmann * ; it is however unnecessary to roughen the 

 cork, and it is advantageons to cover the end, which makes the bottom 

 of the box, with celloidine. The celloidine ought to be thoroughly 

 dried, before the cork is used so as to form a firm coat to prevent the 

 air in the cork from escaping to form bubbles in the celloidine. The 



Blochmänn, This Journal, Vol. I, 1884, p. 226. 



