42C MANUAL OF HISTOLOGY. 



which extended far enough to communicate with that com- 

 ing from an adjacent column. From this point there is a 

 delicate and freely anastomosing network, marking out the 

 spaces between the bundles of fibres of the cutis. The lateral 

 anastomosis, lower down, is not so free, and in the uppermost 

 layers, owing probably to the compression of the bundles of 

 fibres, there is little blue to be seen. From the top of the canal 

 the injection surrounds the base of the hair-follicle, on one side 

 ascending vertically and giving off horizontal branches, and 

 on the other following the interval between the lower border of 

 the erector pili muscles and the fibres of the cutis. The main 

 route is through the canals, there being no penetration from 

 below elsewhere. A similar method of injection of these spaces 

 is seen in certain forms of disease. A subcutaneous, round- 

 celled sarcoma infiltrating the skin, gave a similar configura- 

 tion. Also that form of congenital nsevus which develops in 

 the panniculus adiposus, and in a few days after birth begins 

 to appear on the surface. Another instance is that variety 

 of purulent infiltration of the subcutaneous tissue, which is 

 most frequently seen under thick skin and known as carbun- 

 cle. The wandering cells find their way to the surface through 

 these canals, and thus give the characteristic, punched-out 

 appearance to the skin. 



It is evident from these examples that a free communication 

 exists between the interspaces of the fibrous bundles of the 

 cutis, and the subcutaneous tissue, and that this is effected by 

 no closed system of vessels. 



The special function of these canals is not so evident. In 

 addition to furnishing a route for the blood-vessels and lym- 

 phatics, there would seem to be some connection with the hair 

 and its apparatus. The constant relation which they bear to 

 this structure, and the erector pili muscle, would suggest an 

 arrangement designed to facilitate the action of the muscle, 

 according to Biesiadecki. 1 This muscle, by its contraction, 

 raises the hair from the position which it occupies, nearly hori- 

 zontal to the surface, to a vertical one. Any movement of the 

 root of a lanugo hair would be well nigh impossible, imbedded 

 in the dense tissue of the cutis, were it not for a yielding 

 structure like that of the columns, an elongation of which 



1 Strieker's Handbuch der Lehre von den Geweben des Menschen und der Thiere. 



