87 



a power of deposition or secretion. The most striking illustration I 

 can give in support of this origin of the colouring matter, is drawn 

 from the Ornithorynchus. In it, that part of the hair nearest the skin 

 is colourless, but at the distant extremity it bears a large brown head, 

 in which the pigmentary matter is very abundant, and of a deep brown 

 tint. 



It has been observed, that, if a hair be rolled between the fingers, it 

 has a tendency to go backwards. This arises from its conical shape and 

 its scaly coat. Examined microscopically, each hair is marked by a 

 number of transverse lines — the free margins of scales superimposed one 

 upon another, like tiles upon a roof, making each hair resemble a 

 slated pillar. These scales commence close to the bulb of the hair, 

 and are continuous to its apex. They may readily be made conspicuous 

 by immersing the hair for a short time in pure sulphuric acid. One 

 scale is rarely to be seen embracing a larger portion of the shaft than 

 one-half or two-thirds. They vary greatly in different classes of 

 animals. In some, (the deer and peccari, for example,) they are scarcely 

 to be detected. In the harp seal they are distinct and clear. In man, 

 they frequently require manipulation before they can be seen. In the 

 smaller hairs of the racoon their acute angled edges stand out from the 

 surface like rudimentary spines.* 



In the shrew, fsorexj and some varieties of mice, the scales assume 

 the appearance of a number of cones placed one above another, with 

 their apices all directed backwards. In the bat tribe, especially in some 

 tropical varieties, the scales are more prominent objects than the central 

 shaft. The appeai-ance of this hair can only be compared to a row of 

 large funnels, whose tubes are stuck within each other for a small 

 distance. Mr. Shadbolt has described a somewhat similar hair as occur- 

 ring in one of the Tarantulidee, of which a description is given in the 

 Transactions of the Microscopical Society. 



There is sufficient evidence to prove that the scales are simply an 

 epithelial covering to the hair. They tire continuous with the epidermis, 

 and are first met with in the root of the hair, where the modelling 

 sheath is united to the bulb. By immersion in sulphuric acid, the scales 

 are made to stand out from the stem, giving it the appearance of a 

 bearded ear of corn ; when rubbed off, the scales are found to vary in 

 size and shape — most of them are polyhedral and non-nucleated — some 

 are more or less ovoid and nucleated. In this point also they resemble 

 the epidermis, whose cells are rarely, though occasionally, found to con- 



• To examine these correctly, they should first be well cleaned with ether, and then put 

 up dry — they are spoiled by being put up in balsam. 



