THE SKIN. 71 



tioned. Indeed, in the ox they have been described as 

 simple oval capsules; but, as shown in the annexed engrav- 

 ings, they attain a certain complexity in different parts, 

 becoming flexuous and considerably elongated. The sweat- 

 glands are largely developed in the horse and sheep, but 

 much smaller in the dog. They are, as a rule, colourless and 

 translucent, except in the scrotum of the horse, where they 

 contain a black pigment. 



Between the digits of the sheep is a canal which consists 

 in an inflexion of the skin. It is called the biflex or inter- 

 digital canal, from its position and from the peculiar curve it 

 takes. Its opening is situated anteriorly, above the cleft of 

 the hoof, and a small probe may be inserted downwards and 

 backwards a short distance, where it is stopped, owing to 

 the canal turning upwards and forwards, and terminating in 

 a blunt extremity or cul-de-sac. If a section of the lining 

 of this canal is examined, it is found studded in its deeper 

 parts by yellow bodies, which prove to be coiled tubular 

 glands, containing a yellow secretion. None of the glands 

 present the characters of sebaceous follicles, and Ercolani 

 says that this yellow secretion, mixed with the sebaceous 

 matter 4 discharged through the hair-follicles, loses much of 

 its yellow tint and tenacity. It becomes diffluent, and does 

 not obstruct the canal. 



A group of sweat-glands, emitting a peculiar secretion, is 

 also seen on the face of the sheep a little below the eye, 

 in a depression which is readily felt. In the ewe, other 

 masses of sweat-glands, yielding a peculiarly unctuous secre- 

 tion, are seen on either side of the udder, between the folds 

 of the skin. 



In the mare, a deep layer of sweat-glands is seen, where 

 the skin merges into the mucous membrane over the vulva. 



The sebaceous glands are simple or compound saccular 



