To change the color of the hair various methods and preparations are employed. The principal of these are intended to darken it, but sometimes the contrary is aimed at. Whichever object is desired, it is necessary that the article or preparation employed to carry it out be not of a caustic or irritant nature, capable of injuriously affecting the delicate skin to which it is applied, or that it may be liable to come in contact with, as is the case with many of the nostrums vended for the purpose. Some of the substances that necessarily enter into the composition of hair strains and hair dyes, or that are used in connection with them, possess these objectionable properties in a high degree, and can, therefore, only be safely employed in a state of proper dilution and combination.
If any doubt exists respecting such an article, it is a wise precaution to regard it with suspicion and to test its qualities before applying it for the first time. This may be done by placing some of it on the soft skin of the inner side of the wrist or fore-arm, and allowing it to remain there as long, and under the same conditions, as it is ordered to be left in contact with the hair or skin of the head or face. In this way the injury or loss of the hair, sores, and other serious consequences that too often follow the use of advertised and ill-prepared hair dyes may be generally avoided.
To gradually darken the shade of the hair on these principles, provided its normal sulphur be still secreted by the hair-bulbs and be still present in its structure, it will, therefore, generally be sufficient to occasionally employ a weak solution of any of the milder salts of iron as a hair wash. The menstruum may be water, to which a little spirits and a few drops of oil of rosemary to increase its stimulating qualities have been added. In applying it, the head being first washed clean, care should be taken to thoroughly moisten the whole surface of the hair and the skin of the head with the wash; and its absorption and action should be promoted by the free use of a clean hairbrush. Wine is the favorite solvent for the iron; ale and beer are also sometimes so employed. Most of the fashionable ferruginous hair washes also contain a few grains of acetate of copper or distilled verdigris, the objections to which have been already pointed out.
The daily use of oil or pomatum, with which a few grains of carbonate of lead, lead plaster, or trisnitrate of bismuth, have been blended by heat and careful trituration, has generally a like effect on the hair to ferruginous solutions; so also has a leaden comb, but its action is very uncertain. None of these last are, however, safe for long-continued use. Atrophy of the scalp, baldness, and even local paralysis, have sometimes, though rarely, been caused by them.
When the normal sulphur of the hair is absent, or deficient, the preceding substances fail to darken the hair. In this case the desired effect may often be produced by also moistening the head, say twice a week, with water, to which a little sulphuret of potassium or hydrosulphuret of ammonia has been added.
When it is desired to dye or darken the hair more rapidly, as in a few hours, or even a few minutes, plumbite of lime, plumbite of potassa, or nitrate or ammonia—nitrate of silver—is usually employed. The first is commonly produced by the admixture of quicklime with oxide of lead (litharge), carbonate of lead, or acetate of lead. These ingredients should be in appropriate proportions, but very generally the reverse is the case in those of the shops.
It may be laid down as a rule that when the lime is in greater proportion than about two to one of the oxide, and to the corresponding equivalents of the other substances mentioned, or when the lime has not been prepared in a proper manner, the compound is not safe, and very likely to prove injurious to the skin and hair-bulbs, and perhaps to act as a depilatory. The effects of these lead dyes arise partly in the way previously described and partly by direct chemical action between the sulphur of the hair and the lead which they contain, sulphuret of lead being formed in the surfacial portion of the hair. It is on the last that their more immediate effect depends. If there be no sulphur in the hair, they will not darken it. After the necessary period of contact, they should be gently but thoroughly removed from the hair and skin by rubbing them off with the fingers, and by the use of the hairbrush, the head being then washed clean with tepid water. Should the tint imparted by them not be deep enough, or be too fiery, it may be darkened and turned on the brown or black by moistening the hair the next day with a very weak solution of sulphuret of potassium, or of hydrosulphuret of ammonia.
None of the compounds of lead stain the skin, an advantage which has led to a preference being given to them by many persons who are clumsy manipulators, and to the more extensive use of them than of other hair dyes.
The salts of silver above referred to are more rapid in their action as hair dyes than those containing lead. It is only necessary to wash the hair quite clean and free from grease, then to moisten it with a weak solution of one of them, and, lastly, to expose it to the light, to effect the object in view. Sunlight will fully darken it in a few minutes, but in diffused daylight it will take two or three hours, or longer, to acquire the deepest shade. To avoid this delay and inconvenience, the common practice is, a few minutes after applying the silver solution, to moisten or wet the hair with a solution of sulphuret of potassium, or of hydrosulphuret of ammonia. The effect is immediate, and the full depth of shade which a silver solution of the strength employed is capable of imparting is at once produced. A few minutes later and the hair and skin may be rinsed with tepid water, gently wiped dry, and the hair finally adjusted with the comb. The effect of its application, its rapid action, and the satisfactory nature of the effect produced, all tend to render a solution of nitrate of silver the favorite hair dye of those who have sufficient skill and steadiness of hand to use it properly.
It will be useful here to inform the inexperienced reader that all solutions and compounds which contain nitrate of silver stain the skin as well as the hair, if they be allowed to touch it. These stains may be removed, when quite recent, by rubbing them with a piece of rag or sponge wetted with a weak solution of potassium, of hydrosulphuret of ammonia, or of iodide of potassium; but as this is attended with some trouble and inconvenience, the best way is to avoid the necessity of having recourse to it. The hairdressers commonly adopt the plan of smearing hard pomatum or cosmetique over the skin immediately surrounding the hair to be operated upon, in order to protect it from the dye. By very skillful manipulation, and the observance of due precautions, the hair may be thoroughly moistened with the silver solution without touching the adjacent skin; but this can only be done when the hair of the head is under treatment by a second party.
In reference to the tone and shades of color given by the substances commonly employed to dye the hair, it may be useful to state that the shades given by preparations of iron and bismuth range from dark brown to black; those given by the salts of silver, from a fine natural chestnut to deep brown and black, all of which are rich and unexceptional. The shades given by lead vary from reddish-brown and auburn to black; and when pale or when the dye has been badly applied or compounded, are generally of a sandy, reddish hue, often far from agreeable. However, this tendency of the lead dyes has recently led to their extensive use to impart that peculiar tint to the light hair of ladies and children which is now so fashionable. Other substances, hereafter referred to, are, however, preferable, as imparting a more pleasing hue.
The reddish tint produced by lead, as already hinted, may be generally darkened into a brown, more or less rich, by subsequently moistening the hair with a weak solution of either sulphuret of potassium or hydrosulphuret of ammonia.
The favorite compounds for external use in baldness, and, perhaps, the most convenient and best, are such as owe their stimulating quality to cantharides or Spanish flies, or to their active principle, cantharidine. This application of these drugs has received the sanction of the highest medical authorities, both in Europe and America. The leading professional hair-restorers now rely almost exclusively on cantharides, and all the more celebrated advertised nostrums for restoring the hair contain it as their active ingredient.
Oils and pomades, very strongly impregnated with the essential oil of garden thyme (origanum) and rosemary, and lotions or liniments containing ammonia with a like addition of these essential oils, probably come next in the frequency of their use as popular restoratives of the hair in actual and incipient baldness.