Hair

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.

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