Damar

Permanent Mounting with
Damar Balsam
(From various sources, painful experience, and luck)

Although there are a variety of artificial mounting media available (e.g. Piccolyte, Euparal), only 3 media have proven of any value for permanent ARCHIVAL mounts of gregarines: Canada Balsam, Permount, and Damar Balsam. Canada balsam has proven unsatisfactory for most gregarine work because it tends to collapse and distort specimens, even when used in a very dilute solution. Permount is somewhat more satisfactoy, although it still produces some artifacts and the long term stability of this product, in my own mind, has not been demonstrated. Damar balsam is by far the superior mountant for gregarine work: it produces artifact-free mounts, does not readily bubble, has archival properties superior to those of Canada Balsam, is of an almost neutral pH, and it is inexpensive. Unfortunately, no ready-to-use preparation of Damar Balsam is currently available although the materials are easily obtained and prepared, as directed below.
Damar Gum is available as a raw resin collected from the damar pine along the Pacific Rim. Use only light color damar gum. (Dewaxed gum is heat damaged and unsuitable.) Choose lumps that a relatively free of dirt and debris. Spectrum Chemical Corp. is an excellent supplier. Dark colored lumps have been exposed to high heat and should be rejected. (This has often been a problem with material purchased from Sigma Chemicals.)

Evaluation of Available Mounting Media

Reagents

Preparation of Damar Balsam: Cautiously heat the gum damar over low heat until it melts. Add to the melted mass approximately 6-8 times it's own volume of xylene and stir to form a uniform solution. Filter through a double layer of drip coffee filters. Any fine precipitate that forms overnight should be removed by refiltering the mountant. Damar Balsam will thicken if allowed to evaporate--adjust consistency to your tastes. Specimens cleared in xylene can be mounted directly in Damar Balsam and will harden overnight on a 40 C slide warmer. The mountant, of course, keeps indefinitely.

Damar Gum, Lump
Xylene

25 g
75 ml

Damar Balsam

Dr. R. E. Clopton