432 Mr Gustav Mann 07i Vegetable and Animal Tissues. 



Oil a Method of Preparing Vegetable and Aniraal Tissius for 

 Paraffi^n Imbedding, tvith a few Remarks as to Mounting 

 Sections. By Gustav Mann. 



(Read 11th July 1890.) 

 Requisites — 



I. Picro-corrosive alcohol. 



Heat absolute alcohol to 50° C, saturate with picric 

 acid, and then add bichloride of mercury to 

 saturation. When cool decant. This solution 

 may be made in quantity and kept. 

 II. Absolute alcohol. 



III. Chloroform-alcohol — chloroform and absolute alcohol 



mixed in equal parts. 



IV. Chloroform. 



V. Solid paraffin, melting point 46°-50° C. 

 VI. Short wide-mouthed bottles. 



VII. Best cork stoppers, two for each bottle ; the one 

 fitted with a piece of glass tubing 1 cm. in 

 diameter and 3 cm. long. 

 VIII. Number of glass rods drawn out into fine points, as 

 one must avoid bringing metal instruments in 

 contact with the picro-corrosive fluid. 

 Method — 



A. The fixing and hardening of tissues. 



Place tissue in at least fifty times its bulk of the 

 picro-corrosive alcohol. Leave small objects (up 

 to 1 cubic cm.) for twenty-four hours, larger 

 objects for forty-eight hours and upwards in the 

 fluid. Kee}) the bottle well corked. 



B. The replacement of the picro-corrosive alcohol by pui-e 



absolute alcohol. 

 1. Pour off the hardening fluid till the tissue is just 

 covered. Add absolute alcohol according to 

 the size of the tissue in 1-10 drops every ten 

 minutes, till the tissue is again in fifty times 

 its bulk of fluid. After each addition move 

 the bottle very gently to allow the added alcohol 

 to mix with the hardening fluid. Leave tissue 

 in this diluted mixture for twenty-four hours. 

 In no case should this process be hurried, or 



