ACCORDING TO BRESCHET AND ROUSSEL DE VAUZEME. 425 



the vessels and nerves which enter into, or go out from the derm. 

 d, An interval filled up by capillary filaments. 



Of the Derm, 



The external surface of the derm, is lined by a very thin 

 adherent membrane, which is reflected over the tops of the 

 papillary bodies and forms their neurilema. The horny or 

 epidermic matter is secreted in the grooves between the papillae, 

 and is moulded around all the inequalities, the form of which is 

 exactly impressed on all the layers of the epidermis. In serpents, 

 the derm, has a singular arrangement ; it is elevated in imbri- 

 cated projections, covered by a thin layer of epidermis ; these 

 are called scales. In fishes, on the contrary, the surface of the 

 derm is smooth, and the scales are formed only of the horny 

 matter. The derm is a membrane, the fibres of which are 

 solidly interlaced together, with interstices for the passage of 

 vessels, nerves and canals, and in which are lodged many 

 organs, as has been shown in the plan, page 423.* 



Of the Papillary Body, or JNeurothelic Apparatus.^ 



This consists of a series of little prominences on the upper 

 surface of the derm, the cleft at the top into two portions, each of 

 which is composed of a bundle of nerves and vascular fila- 

 ments the bourgeons sanguins of Gaultier. The form of each 

 papilla is that of a cone. The base is expanded in the upper 

 surface of the derm, and its two prominences or villi, termi- 

 nating in a rounded point, are received in the horny layers of 

 the epidermis, like a sword in its sheath, (see page 426.) 

 The direction of the papilla is slightly oblique in the epider- 







* The method adopted by these writers for microscopical examination of the 

 skin, was to take a piece of recent skin in which the vessels were distended by 

 cadaveric accumulation of blood, or filled with injection. A portion from the 

 heel is preferable. This is to be allowed partially to dry, and the thinnest pos- 

 sible transparent slice, cut off vertically. This is to be placed upon a piece of 

 moistened glass and examined under the microscope with the use of a lamp 

 and reflector. In this way they were able readily to see, and isolate with curved 

 cataract needles, all the vessels, nerves and glandula apparatus of the skin. p. 



f From ne.uron, nerve, and thtla, papilla. 



36* 



