MOUNTING 763 



vious dehydration, the edge of the cover glass being, after some hours, 

 covered with a ring of King's cement. 



Glycerin jelly is also serviceable, and does not require cementing of 

 cover glass. 



Neutral Balsam. Sections may frequently be rendered more per- 

 manent by the use of neutral balsam, prepared as follows : 



Dilute Canada balsam with xylol until it acquires a very thin watery 

 consistence. Add sodium bicarbonate in excess. Shake thoroughly, and 

 allow to stand in a stoppered bottle for twelve hours or more. Filter; 

 this is readily, though slowly, accomplished if the dilution is sufficient. 

 Permit the solution to stand in an open vessel, protected from, dust, 

 until it evaporates to the proper consistence for use. 



Gum-Damar. This material, also dissolved in xylol, is in some re- 

 spects even a better mounting medium than balsam; it does not turn 

 yellow with age. 



Euparal. This new mounting medium is for most purposes the 

 best. Sections are mounted direct from 95 per cent, alcohol. Delicate 

 tissues may thus be spared the passage through absolute alcohol and 

 oil. This curtailment of the technic is also a saving of expense. 

 Euparal has, moreover, a lower index of refraction than balsam or 

 gum-damar, and is thus more favorable for the demonstration of cyto- 

 logic details (see Lee, "Vade Mecum," 8th ed., p. 247). For method of 

 preparation see Shepherd, Trans. Am. Micr. Soc., vol. 37, p. 131, 1918. 



For more detailed and extensive information on histologic technic, and 

 microchemic methods, the following books should be consulted: 



1. Lee: "The Microscopist's Vade Mecum" (8th ed., 1913). Blakis- 



ton, Phila. 



2. Mann: "Physiological Histology." Oxford, 1902. 



3. Guyer: "Animal Micrology." Univ. of Chicago Press, 1906. 



4. Hardesty: "Neurological Technique." Univ. of Chicago Press, 



1902. 



5. Kingsbury: "Laboratory Directions in Histology Histological 



Technique." Ithaca, N. Y., 1910. 



6. Mallory and Wright: "Pathological Technique." Saunders. 



7. Enzyklopredie der mikroskopischen Technik " (2d ed., 1910). 



Urban und Schwarzenberg, Berlin. 



8. Gage: "The Microscope" (llth ed., 1911). Comstock Pub. Co., 



Ithaca, N. Y. 



