1196 Journal of Applied Microscopy 



Flattening and Fixing Paraffin Sections on Slide. 



One of the difficulties in mounting paraffin sections in series is the loss due 

 to imperfect fixing on the slide. 



The following methods are generally recommended : Water (Lee's Vade- 

 Mecum, sec. 182, 5th ed.); alcohol (70 per cent, alcohol is used instead of water. 

 Method described in above reference); Mayer's albiimi?i (Lee's Vade-Mecum, 

 sec. 183, 5th ed.). Each of these methods is open to some objections, either on 

 account of extreme care necessary for good results or clouding of sections in 

 staining. 



Of these, the alcohol method seems to be the most satisfactory, as it does not 

 require that the slides be absolutely clean, nor are the sections clouded in stain- 

 ing as sometimes occurs in the albumin method. The improvement on the 

 alcohol method suggested by Eisen (Zeit. f. wiss. Micros. Bd. xvi) makes it as 

 certain as the albumin method, without its objectionable features. 



The essential steps in the process are as follows : 



a. Flood the slide with 70 per cent, to 85 per cent, alcohol. Arrange sec- 



tions in order. Hold slide a few inches above small flame until sections 

 are flattened. 



b. Drain off surplus alcohol (use filter-paper or cloth). Rearrange 



sections in desired positions. 



c. Cut out two pieces of smooth blotting paper same size as slide. Wet one 



in same strength alcohol as used in {a^, and place over sections. 

 Over this put the other piece dry. Pass small rubber roller (such as 

 used by photographers), firmly over the dry blotting paper two or 

 three times. Instead of using the roller, any weight with smooth sur- 

 face may be pressed against the blotting paper. The object of this 

 step is to flatten the sections completely, so that every part of the 

 section will come in contact with the slide. 



d. Remove any lint which adheres to the slide and dry in a place protected 



from dust. At the ordinary temperature of the room, two or three 

 hours are necessary for complete drying. The process may be has- 

 tened by keeping the sections at a temperature a few degrees below 

 the melting point of the paraffin (below 40° C). 

 If this method has been carried out carefully, the sections may be taken 

 through as many stains or reagents as desired, or left indefinitely in any solu- 

 tion which will not act chemically on them. B. M. Davis. 

 Biological Laboratory, State Normal, Los Angeles, Cal. 



A new building is being erected, at a cost of $125,000, for the Medical 

 Department of Cornell University. It will be the finest building on the Cornell 

 campus, and will offer facilities for scientific and practical study which are not 

 excelled by any institution in the world. 



