113 
each other and connected together by numerous loops, forming a sort 
of network around them; but never such an abundant mesh as is 
figured by BupgeE *) about embryonal vessels. 
Lymphatics associated with Veins. The remaining two 
lymph-vessels which arise from the terminal bronchus pass one on 
either side to the small veins which arise from this point, and have 
usually more of a spiral course than those about the artery. They 
unite with other lymphatics at the point where the vein joins a larger 
branch giving rise to a larger lymph-vessel. We also have lymph- 
vessels passing from the bronchus to the veins which are found at the 
point where a branch leaves the main bronchus. We have theretore 
at the point where bronchi branch, practically the same relation of 
lymph-vessels as at the terminal bronchus: three lymphatics, one of 
which passes to the artery, the other two to the veins. 
Finally we have a lymph-vessel accompanying the veins that pass 
to the pleura and uniting with the network of lymph-vessels found in 
the pleura. 
The small veins have but a single lymph-vessel accompanying 
them, but the larger veins have two, and in a few instances I have 
found three main vessels, which are connected by loops, forming a 
network with a long mesh about the veins. 
Lymphatics of the Pleura. In successful injections one sees 
on the surface of the lung an extensive network of large lymph-ves- 
sels in the mesh of which lies a network of finer vessels. The lym- 
phatics of the pleura form at the hilus of the lung three, four or five 
large trunks which anastomose at this point with the lymphatics be- 
longing to the lung. 
Along the border of the lung the large lymph-vessels of the 
pleura often dip into the lung for some distance only to come to the 
surface again after a short interval. I have never found any bran- 
ches given off from the loop which is thus formed in the lung to the 
lymphatics of the lung. 
The lymphatics of the pleura have a large number of valves, but 
as they communicate freely with each other, the vessels fill readily 
with the injection mass, a point which was noted by CRUIKSHANK, but 
the valves prevent the passage of the injection mass into the lym- 
phatics of the lung. 
4) A. Bones, Untersuchungen über die Entwickeluug des Lymph- 
systems beim Hühnerembryo. Archiv f. Anat. u. Phys., Anatom. Abth., 
1887. 
