The hair : its growth, care, diseases, and treatment / by C. Henri Leonard.

Date:
1880
Catalogue details

Licence: Public Domain Mark

Credit: The hair : its growth, care, diseases, and treatment / by C. Henri Leonard. Source: Wellcome Collection.

Provider: This material has been provided by the Royal College of Physicians of Edinburgh. The original may be consulted at the Royal College of Physicians of Edinburgh.

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    The Fibrous Portion.—This portion of the shaft which lies just beneath the epithelial or outer coating, and surrounds the medullary portion on all sides, 2, 2, Fig. 10, goes to make up the bulk of each cylinder. The cells forming this portion are elongated, contain long nuclei, and are grouped together in fusiform bundles. Their length is to of an inch; their breadth ^^oir TsVo inch. A few air cells are also found in this coating in the lighter colored hairs, but in the black their place is fully taken by the increased number of pigment granules. These cells are best brought out by treating the section to be examined with a dro]) of strong sulphuric acid (sometimes it is necessary they should macerate in the acid half an hour, before showing them nicely), then pressing the covering-glass firmly down upon them, so as to separate the cells as much as possible. This portion of the hair is the chief source of its strength, for hair has a great deal of strength, when it is taken in the aggregate. A single hair will support, if healthy, four ounces. The supporting power, though, varies with the size of the hair- . cylinder, as found in different individuals, and also with its color and with the age of the individual, and the state of the health of the individual from which it is taken. Thus, a hair, light brown in color, and from a person aged eighty, would support but one and one-quarter ounces without breaking. A blonde hair filament from a child ten years of age, broke under a strain of two and one-quarter ounces ; another blonde filament from a young lady, twenty-five years of age, broke on two and one-half ounces; a dark brown hair from the head of a lady, a.ged seventeen years, broke at the same weight; a dark brown hair from a person aged thirty-eight, a red one from another