270 ON CUTANEOUS AND [BOOK in. 



occasionally in the inside of large nerve trunks. Lastly, they are 

 scattered over the sympathetic nerves of the abdomen. It is 

 obvious that their functional connection with cutaneous sensations 

 is a very indirect one ; but to this point we shall return. 



871. Grandri/'s Corpuscles. Although these are not found 

 in connection with the skin of man, or indeed with true skin 

 anywhere, their occurrence being limited to the dermis of the 

 mucous membrane of the beak, of the tongue and of the palate 

 of certain birds, it will be desirable to say a few words about 

 them. 



In its simplest, typical form a corpuscle of Grandry, about 

 50 /A in diameter, consists of two nearly hemispherical or dome- 

 shaped cells placed with their flat surfaces face to face. Each cell 

 contains a conspicuous round nucleus surrounded by granular cell 

 substance ; it has all the appearance of a large well-nourished 

 epithelium cell. The two cells are surrounded by a capsule of 

 connective tissue bearing nuclei. A medullated nerve fibre with 

 its neurilemma and sheath of Henle, approaching the corpuscle in 

 a more or less coiled course, joins it at the side at the level of the 

 junction of the two cells. Here the sheath of Henle and probably 

 also the neurilemma become continuous with the capsule, the 

 medulla ceases, and the naked axis cylinder passing in between 

 the opposed flat surfaces of the cells ends in the centre between 

 them in a round flattened biconvex disc or " plate," forming as it 

 were a " buffer " between the two cells in their central region. 

 As far as can be ascertained there is no continuity between the 

 axis cylinder plate and the substance of either of the cells ; the 

 former simply lies in contact with each of the latter. These 

 epithelium cells, if we may venture so to call them, appear to be 

 "subsidiary" cells, assisting in some unknown way the equally 

 unknown functions of the terminal plate of the axis cylinder , and 

 we may perhaps draw an analogy between them and the sub- 

 sidiary cells of the organs of smell and taste. As we shall see, 

 the nerves of the skin enter in the epidermis into similar 

 relations with special cells distributed among the ordinary cells 

 of the Malpighian layer in certain situations. 



Sometimes there are three such cells, the uppermost and 

 undermost being hemispherical or dome-shaped, and the middle 

 one having the form of a disc or short cylinder, all being sur- 

 rounded by the same capsule. In such a case the nerve fibre 

 divides into two branches, one forming a terminal disc between 

 the upper and middle cell, the other between the middle and 

 lower cell. Where there are more than three cells the divisions 

 of the nerve fibre are correspondingly increased. Sometimes a 

 compound corpuscle is formed by the aggregation of several 

 simple corpuscles, each with its epithelium cells and one or more 

 terminal plates of an axis cylinder. 



872. Touch Corpuscles. These are minute bodies of an 



