424 MANUAL OF HISTOLOGY. 



branch on either side, which anastomoses sparingly through 

 subdivisions with the adjacent arterioles in the middle layer of 

 the cutis, and give origin to the papillary and sub-papillary 

 network of capillaries, which here can be considered as one 

 and the same. At the point of bifurcation of the main vessel, 

 branches are given off which ascend farther in the canal and 

 form a delicate net- work surrounding the sudoriparous gland 

 ("Wundernetz"). The anastomosis of the vessel about the 

 hair-follicle is particularly rich and fine, and unites intimately 

 with the superficial layer of capillaries. The hair-follicle, with 

 its subjacent fat-column, thus forms the centre of a rich system 

 of arterioles and capillaries, which extend from the panniculus 

 adiposus to the papillae. 



The lymphatics. The following experiments were made to 

 determine, the question of the presence of lymphatics in these 

 canals, and also to observe to what extent fiuids and particles, 

 pressed up from below, could be forced to the surface. 



Skin was taken from the body of a lean adult, twenty-four hours after death. 

 A small amount of the loose areolar tissue was left adherent to its lower sur- 

 face. The skin being prepared by warming for a few minutes in water of 

 about 90 F., Berlin blue was injected, by means of a subcutaneous syringe, 

 into the loose areolar tissue, which was rapidly distended by the fluid. The 

 specimen was then thrown into strong alcohol. A similar fragment of skin 

 was stretched like a drum, over the end of a brass cylinder, to which it was 

 firmly attached by an open brass cap and screws. The cylinder being held 

 vertically, Berlin blue was poured upon the skin, the upper surface of which 

 looked downward. A rubber cork, perforated by a glass tube, was securely 

 fastened to the top of the cylinder, and the tube was connected with an appa- 

 ratus designed to exert any atmospheric pressure required. Pressure sufficient 

 to raise a column of mercury twenty-eight millimetres was continued for an 

 hour and a half, the skin being pressed out with great force in dome-shape 

 at the bottom of the cylinder, which was kept during this time in blood-warm 

 water. The specimen was then placed in alcohol. It was observed that the 

 injection mass had gone, at one or two points, to the surface, and on making 

 vertical sections of the skin the next day, the cutis was found to be penetrated 

 by the mass in vertical blue lines, which united at various intervals by hori- 

 zontal branches, occasionally so numerous as to present an almost continuous 

 blue surface. The subcutaneous areolar tissue was almost uniformly colored 

 blue. 



Opinions on the character and distribution of the lymphat- 

 ics of the skin seem to differ. For instance, Neumann de- 

 scribes them as vessels distributed through the skin in two 



