Slightly More (Complicated) Hair

I’m constantly amazed at the ease with which one can obtain certain chemicals; in the old days you had to know the right people, now you just have to know how to search the web. Of course in the very old days your local pharmacist would just give you some… -K

The slide I’ll describe today is very much the same as the previous, differing only in the treatment one uses prior to mounting. While very fine results may be had by the process described previously, a little more effort can deliver a superior preparation. This method is not the acme of hair mounts either. There is seemingly always a little bit of improvement that one can make when it comes to mounting. Once one begins to gain a degree of comfort and familiarity with the process, ideas for improvement abound. The successful student is one who does not see the procedures of others as a rule-book but as an inspiration.

Hair is among the materials that could be mounted directly into resin after collection. In the previous entry that is very nearly what was done. A brief rinse in alcohol was performed primarily to ease manipulation, rather than to provide for dehydration as one may have reasonably guessed. Fortunately, the composition of hair is such that even freshly collected hair is essentially “dry” to begin with. Natural oils are the primary moisture in any hair and this oil will have some effect on the refraction of the mounting medium after the slide has cured. To provide a better level of resolution of the margins of a strand of hair one must remove the oil from the hair so that the refractive index of the mountant is uniform.

Most every microscopist will posses a number of solvents that may be used with success to clean a hair of oils prior to mounting. One solvent in particular enjoyed a profound popularity, for this purpose and others fifty years ago: ether. Sulfuric ether (more apt to be found today as ethyl or diethyl ether) is a highly volatile inflammable solvent. It is heavier than air and has a rather distinct odor that is markedly less beckoning than chloroform, neither of which one should inhale, and both of which have their uses in microscopic mounting.

The distillation of sulfuric ether is not complicated and is one of the more common bits of home chemistry achievement one sees on various web sites. Do not attempt the distillation of sulfuric ether at home without the proper training. Far too many people have far too high an opinion of their abilities and will run into all manner of problems. I have seen videos of ether being distilled on kitchen hot-plates that make me marvel at the fortune of others in not catching fire. Ether is available from many reputable chemical supply houses at a very economical cost. If one is unable to locate ether, various similar solvents may be used. Xylene and toluene are effective substitutes if local laws or personal caution dictates.

To remove totally the natural oils from a sample of hair one should make a solution of one part sulfuric ether to one part anhydrous alcohol. This is one of the situations where I do not recommend the use of denatured alcohol as an alternative to anhydrous alcohol. Some formulations of denatured alcohol may provide suitable results, but as the amount of solution required is very small, anhydrous ethanol can be used without it being a great waste. Alternatively, one may use anhydrous isopropanol or even anhydrous methanol, though isopropanol is likely to be the most readily available and least expensive. Be sure to mix the solution in an amber glass vial as ether has the potential to form hazardous peroxides in the presence of light.

With the ether-alcohol solution prepared, take in a forceps the hair to be mounted and carefully agitate it in the vial for from forty to sixty seconds. Afterwards deposit the hair very near the center of a clean slip and mount it as described in the previous post. As mentioned previously this treatment will remove the natural oils from the hair and allow for the mountant to form a material of uniform refractive index around the hair. This will permit the scale pattern, and interior structure of the hair to be observed somewhat better than that of a hair which is mounted directly, or through alcohol and a clearing agent alone. It it will not provide as clear an image of the scale pattern as a scale cast, but that is another sort of slide entirely.


As a bald gentleman I find it distasteful to spend any time thinking of a better title. Fortunately, the gravitas that comes of being a bald chap with eyeglasses and a deep voice nearly makes up for the lack of coiffe. -K

Hair (note in the following the word hair is meant to indicate animal hair) is to be found very nearly everywhere. Entering any building which humans occupy even on an intermittent basis one is sure to find a strand here or there. If one examines a shirt or jacket, hair will be found, this time of year one might well be wearing a shirt knit from the hair of sheep. Most people don’t give the hair much thought beyond grooming their own, but the microscope owner might do well to consider it for a time.

Hair is among the easier things to examine in temporary or permanent mounts. Far from the smooth thread that it appears to the naked eye, under the lens of a microscope it can be surprisingly diverse, and I’m not writing of curl, coarseness, or color. Hair is the subject of a good deal of forensic investigation and a the techniques surrounding it are myriad. Specialized means of taking longitudinal and cross sections have been developed, differing mountants advocated for different types of hair, various adhesives recommended for scale impressions et cetera. I imagine most schools still introduce students to the microscope with the printed letter “e” slide, and leave out hair.

Two slides will be produced, one using more advanced methodology, and the other more expedient. The results will be largely similar and will demonstrate that fine permanent mounts of hair may be produced without overmuch difficulty by those of any skill level. Forgoing more complex methods only regular segments of hair will be mounted, no sectioning is required other than to cut to length the hair so that it will fit beneath the coverglass.

For the first, simpler, mount one will require a fine forceps, a cleaned coverslip and coverglass, the preferred resinous mountant, alcohol of the highest concentration available (for Euparal and similar mountants) or an essential oil or xylene (for Balsam or Damar mountants) and a fine shears. If using alcohol or a clearing agent a watch glass or similar vessel will be needed. One will also require hair, human hair can be employed, but will often prove less interesting than that of other mammals. Because hair is dead, composed primarily of keratinous protein, and actually holds moisture very poorly, the use of alcohol or any clearing agent may be considered optional. They will be used in the following example only because it makes the manipulation of the hair to be mounted less delicate.

In the slide I will make the hairs used will be human, and mouse. The hairs will appear very different under the lens and to better illustrate that difference on each slide will be placed a human hair alongside a mouse hair. If one has a pet mouse, or an acquaintance who does, then the mouse hairs may be collected without too much difficulty from within the nest the next time the pets enclosure is cleaned. Human hair may be of course obtained by plucking a strand from any willing head.

Cut the hairs to be mounted so that they are in length less than half of the diameter of the coverglass used. Depending on the color of the hairs collected it will be helpful to work over a sheet of black or white paper. Place the cut hair from one subject into a watch glass of alcohol (if using Euparal) or Xylene (if using balsam) for a moment and then transfer to the cleaned glass slip. Place the hair very near to the center of the slip and release it from the forceps while it still remains moist, the liquid will help to cause the hair to cling to the slip and make positioning it more simple. Do likewise with the hair from the second subject, placing it very near to that of the first on the slip.

Place only the smallest drop of mountant in the center of a cleaned coverglass. Allow the mountant to spread out until it almost reaches the edges of the cogverglass and lower it onto the slip. If the mountant is not allowed to spread out before it is placed on the slip, the hairs will be displaced outward as the coverglass settles. Using hairs that have been cut to less than half the diameter of the coverglass used will ensure that even if they are displaced they will not approach the edge of the coverglass and spoil the mount.

If only hair from one specimen is to be mounted, placing it in the exact center of the slip and lowering the coverglass so that the mountant presses it to the slip will help also help to prevent its being displaced as the coverglass settles. Alternatively one may place two or more hairs so that they intersect in the center of the slip and thereby create a mount that allows for one to practice identifying the relative depth of specimens on a slide.