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IOWA ACADEMY OF SCIENCE Vol. XXIV, 1917 
the movement of the injecting mass watched very carefully to 
render the results trustworthy, because filling the veins with 
the mass directly from the point of injection does occur in some 
instances. In this connection the writer has considered as le- 
gitimate proof only those instances in which the injecting mass 
has been seen to leave the lymphatic channels and enter the 
veins, or, in which a dissection could be made to show a con- 
nection between a lymphatic vessel and a vein. Such conditions 
do not occur in every specimen injected, so a large number is 
necessary to furnish a basis for drawing conclusions. Further- 
more, the physiological condition of the animal must be taken 
into consideration. There is evidence that specimens killed 
with illuminating gas give a higher percentage of instances of 
venous connections and show a finer network of plexuses than 
specimens killed with ether or chloroform. There is a basis also 
for the belief that the degree of activity, the length of time 
after feeding and the physical condition of the^animals are facts 
which vary the response of the lymphatic vessels to the inject- 
ing mass. Thus it may be that in part the lack of constancy in 
the venous communications is due to these conditions. 
In aboat twenty-five per cent of the specimens injected, portal 
vein taps can be shown by observation and dissection. Two 
cases of particular interest were observed. When the most 
distal intestinal node was injected the mass was seen to run 
along the lymphatic channel from this node to the region just 
dorsal to the pyloric end of the stomach ; there it entered the 
portal vein and ran into the liver and out toward the injected 
node, thus giving as clear a demonstration of this connection 
as could be demanded. 
The connection in the portal vein is of particular interest in 
connection with the experiments carried on by physiologists. If 
the amount of fat contained in the lymph taken from the thor- 
acic duct, after feeding an animal a known quantity of fat, be 
added to the amount lost in the feces, a variable amount is 
shown to have disappeared by some other route. Physiologists 
have considered that this amount must be taken up directly 
by the venous capillaries of the villi, even though it is not a 
satisfactory explanation to them. The portal vein communica- 
tion of the intestinal lymphatic channel can account for this 
variable difference. 
